研究者データベース

研究者情報

マスター

アカウント(マスター)

  • 氏名

    佐藤 敏文(サトウ トシフミ), サトウ トシフミ

所属(マスター)

  • 工学研究院 応用化学部門 分子機能化学分野

所属(マスター)

  • 工学研究院 応用化学部門 分子機能化学分野

独自項目

syllabus

  • 2020, 大学院共通授業科目(一般科目):自然科学・応用科学, Inter-Graduate School Classes(General Subject):Natural and Applied Sciences, 修士課程, 大学院共通科目, Self-assembly, block copolymers, nanoparticles, thin films, nanolithography, electronic devices
  • 2020, 大学院共通授業科目(一般科目):自然科学・応用科学, Inter-Graduate School Classes(General Subject):Natural and Applied Sciences, 修士課程, 大学院共通科目, living anionic polymerization, macromolecular architecture, multiphase polymers, nanostructure, surface structure
  • 2020, 応用化学特別講義, Advanced-Applied Chemistry, 修士課程, 総合化学院, Self-assembly, block copolymers, nanoparticles, thin films, nanolithography, electronic devices
  • 2020, 応用化学特別講義, Advanced-Applied Chemistry, 修士課程, 総合化学院, Step-Growth Polymerization, functional polymers, high-performance polymers/metal oxides hybrids, triphenylamine (TPA), optical, electrochromic, and optoelectronic applications.
  • 2020, 応用化学特別講義, Advanced-Applied Chemistry, 修士課程, 総合化学院, living anionic polymerization, macromolecular architecture, multiphase polymers, nanostructure, surface structure
  • 2020, 応用生物化学A(機能性高分子特論), Applied Biochemistry A (Advanced Functional Polymer), 修士課程, 総合化学院, 高分子合成, 精密重合,リビング重合,ラジカル重合,カチオン重合,アニオン重合,配位重合、機能性高分子,高分子構造,高分子設計, 高分子溶液, 相分離挙動
  • 2020, 応用化学特別講義, Advanced-Applied Chemistry, 修士課程, 総合化学院, Colloidal phenomena, Interfacial phenomena, Molecular Simulations
  • 2020, 先端総合化学特論Ⅱ, Modern Trends in Chemical Sciences and Engineering II, 博士後期課程, 総合化学院, Self-assembly, block copolymers, nanoparticles, thin films, nanolithography, electronic devices
  • 2020, 先端総合化学特論Ⅱ, Modern Trends in Chemical Sciences and Engineering II, 博士後期課程, 総合化学院, Step-Growth Polymerization, functional polymers, high-performance polymers/metal oxides hybrids, triphenylamine (TPA), optical, electrochromic, and optoelectronic applications.
  • 2020, 先端総合化学特論Ⅱ, Modern Trends in Chemical Sciences and Engineering II, 博士後期課程, 総合化学院, living anionic polymerization, macromolecular architecture, multiphase polymers, nanostructure, surface structure
  • 2020, 先端総合化学特論Ⅱ, Modern Trends in Chemical Sciences and Engineering II, 博士後期課程, 総合化学院, Colloidal phenomena, Interfacial phenomena, Molecular Simulations
  • 2020, 専門横断科目(一般科目):自然科学・応用科学, Inter-Faculty Classes(General Subject):Natural and Applied Sciences, 学士課程, 専門横断科目, Scattering techniques, light, x-rays, neutrons, polymers, colloids
  • 2020, 工学特別講義, Special Lecture on Engineering, 学士課程, 工学部, living anionic polymerization, macromolecular architecture, multiphase polymers, nanostructure, surface structure
  • 2020, 工学特別講義, Special Lecture on Engineering, 学士課程, 工学部, Step-Growth Polymerization, functional polymers, high-performance polymers/metal oxides hybrids, triphenylamine (TPA), optical, electrochromic, and optoelectronic applications.
  • 2020, 工学特別講義, Special Lecture on Engineering, 学士課程, 工学部, Self-assembly, block copolymers, nanoparticles, thin films, nanolithography, electronic devices
  • 2020, 高分子化学Ⅰ, Polymer Chemistry I, 学士課程, 工学部, 高分子・分子量・分子量分散度・逐次重合・連鎖重合・熱可塑性樹脂・熱硬化性樹脂
  • 2020, 物質変換工学, Applied Chemistry and Biochemistry, 学士課程, 工学部, 有機合成,有機材料,化学プロセス,反応器設計,生体材料,高分子材料,分子機能,無機材料,複合材料,電子材料,光機能材料
  • 2020, 工学特別講義, Special Lecture on Engineering, 学士課程, 工学部, Colloidal phenomena, Interfacial phenomena, Molecular Simulations

PositionHistory

  • 大学院総合化学院副学院長, 2016年4月1日, 2018年3月31日
  • 大学院総合化学院副学院長, 2018年4月1日, 2020年3月31日

researchmap

プロフィール情報

学位

  • 博士(工学)(北海道大学)
  • 修士(工学)(北海道大学)

プロフィール情報

  • 佐藤, サトウ
  • 敏文, トシフミ
  • ID各種

    A-5316-2012, 200901006558592385

対象リソース

業績リスト

研究キーワード

  • 環化重合   開環重合   カチオン重合   糖鎖ポリマー   ハイパーブランチポリマー   環境材料   アルミニウム触媒   サレン錯体   両親媒性ポリマー   多分岐糖鎖   ジエポキシ化合物   ジアンヒドロ糖   光学活性   高分子合成   不斉反応   ポリ乳酸   ナノ材料   エナンチオ選択性   分子認識   亜鉛触媒   立体選択重合   ナノカプセル   エチルグリコリド   メタロセン触媒   アンヒドロ糖   ハイパーブランチ糖鎖高分子   高分子構造・物性   生分解性高分子   水素移動重合   生分解性   有機化学   高分子化学   Polymer Chemistry   

研究分野

  • ナノテク・材料 / 無機・錯体化学
  • 環境・農学 / 環境材料、リサイクル技術
  • 環境・農学 / 環境負荷低減技術、保全修復技術
  • ライフサイエンス / 生体材料学
  • ライフサイエンス / 生体医工学
  • ナノテク・材料 / 高分子化学
  • ナノテク・材料 / 高分子材料

経歴

  • 2013年04月 - 現在 北海道大学 大学院工学研究院 教授
  • 2016年04月 - 2020年03月 北海道大学 大学院総合化学院 副学院長
  • 2007年04月 - 2013年03月 北海道大学 大学院工学研究科 准教授
  • 2002年02月 - 2007年03月 北海道大学 創成科学共同研究機構 流動研究員
  • 1997年04月 - 2007年03月 北海道大学 大学院工学研究科 助手
  • 1998年06月 - 2000年04月 日本学術振興会 海外特別研究員
  • 1996年10月 - 1997年09月 北海道大学 工学部 助手
  • 1994年04月 - 1996年09月 日本学術振興会 日本学術振興会特別研究員DC1

学歴

  •         - 1996年   北海道大学   工学研究科   分子化学専攻
  •         - 1994年   北海道大学   工学研究科   合成化学工学専攻
  •         - 1992年   北海道大学   工学部   合成化学工学科

委員歴

  • 2021年04月 - 現在   北海道大学大学院工学研究院応用化学部門   部門長
  • 2007年 - 現在   高分子学会   北海道支部理事   高分子学会
  • 2008年   高分子学会北海道支部 若手研究会   運営委員   高分子学会北海道支部 若手研究会
  • 2008年   日本化学会   北海道支部庶務理事   日本化学会
  • 2006年 - 2007年   高分子学会北海道支部 若手研究会   代表   高分子学会北海道支部 若手研究会

受賞

  • 2017年01月 北海道大学 平成28年度北海道大学教育総長賞奨励賞
     
    受賞者: 佐藤 敏文
  • 2017年01月 北海道大学 平成28年度北海道大学研究総長賞奨励賞
     
    受賞者: 佐藤 敏文
  • 2016年11月 先端錯体工学研究会 2015年度 先端錯体工学研究会賞
     
    受賞者: 佐藤 敏文
  • 2016年01月 北海道大学 平成27年度北海道大学研究総長賞奨励賞
     
    受賞者: 佐藤 敏文
  • 2013年 公益社団法人 高分子学会 高分子学会旭化成賞
     バイオベースマテリアルを用いた機能性単分子ミセルの開発 
    受賞者: 佐藤 敏文
  • 2005年 日本化学会北海道支部研究奨励賞
  • 2005年 The Award for Encouraging Prize from Hokkaido Branch of the Chemical Society of Japan
  • 1998年 高分子研究奨励賞
  • 1998年 The Award for Encouragement of Research in Polymer Science
  • 1997年 北海道大学大学院工学研究科 大塚 博先生記念賞
  • 1997年 The Prof. Otsuka Memorial Prize from Division of Molecular Chemistry, Hokkaido University
  • 1992年 北海道大学工学部 大島 義清先生記念賞
  • 1992年 The Prof. Oshima Memorial Prize from Department of Chemical Process Engineering, Hokkaido University

論文

  • Yoshinobu Mato, Maho Sudo, Hironori Marubayashi, Brian J. Ree, Kenji Tajima, Takuya Yamamoto, Hiroshi Jinnai, Takuya Isono, Toshifumi Satoh
    Macromolecules 54 19 9079 - 9090 2021年10月12日 [査読有り][通常論文]
  • Dai-Hua Jiang, Brian J. Ree, Takuya Isono, Xiao-Chao Xia, Li-Che Hsu, Saburo Kobayashi, Kuan Hoon Ngoi, Wei-Cheng Chen, Chih-Chun Jao, Loganathan Veeramuthu, Toshifumi Satoh, Shih Huang Tung, Chi-Ching Kuo
    Chemical Engineering Journal 418 129421 - 129421 2021年08月 [査読有り]
     
    Bio-derived optoelectronic material is captivating and sustainable research as it reduces the environmental toxicity and comforting the wearable aspects. Our research involves the synthesis of series of bio-derived polyfluorene-block-poly(δ-decanolactone) (PF-b-PDL) conjugated block copolymers through smart one-pot procedure that involves simple purification for fabricating touch-responsive light-emitting diode (LED) devices. Compared with PF homopolymer, the block copolymers exhibit higher photoluminescence quantum yields and higher exciton binding energies. PF -b-PDL specifically exhibits external quantum efficiency (EQE %) (~6 times higher than PF homopolymer). Moreover, because of coily PDL block inducing a highly stable bound state in block copolymer generating the increment in PL lifetime and exciton binding energies than the homopolymer. Furthermore, the diblock copolymers device exhibits fully solution processability, higher carrier recombination efficiency, flex-stretch stability, good structural integrity and mechanical endurance highlighting the brighter potential of our bio-derived block copolymers for fabricating highly durable wearable stretchable nano and microelectronic devices. 18 13
  • Satoshi Katsuhara, Yasuko Takagi, Naoki Sunagawa, Kiyohiko Igarashi, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    ACS Sustainable Chemistry & Engineering 2021年07月08日 [査読有り]
  • Brian J. Ree, Yusuke Satoh, Takuya Isono, Toshifumi Satoh
    ACS Macro Letters 811 - 818 2021年06月14日 [査読有り]
  • Mahmoud M. Abd Elwakil, Tianle Gao, Takuya Isono, Yusuke Sato, Yaser H. A. Elewa, Toshifumi Satoh, Hideyoshi Harashima
    Materials Horizons 2021年06月 [査読有り]
     

    Engineered lipomers coming from sustainable sources can efficiently bypass the liver to deliver a genetic message to the lungs after systemic administration without targeting ligands.

  • Tomohisa Watanabe, Satoru Chimura, Yubo Wang, Tomoko Ono, Takuya Isono, Kenji Tajima, Toshifumi Satoh, Shin-ichiro Sato, Daichi Ida, Takuya Yamamoto
    Langmuir 2021年05月28日 [査読有り]
  • Kodai Watanabe, Noya Kaizawa, Brian J. Ree, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    Angewandte Chemie International Edition 2021年05月26日 [査読有り]
  • Xiaochao Xia, Ryota Suzuki, Kaoru Takojima, Dai-Hua Jiang, Takuya Isono, Toshifumi Satoh
    ACS Catalysis 5999 - 6009 2021年05月02日 [査読有り]
  • Brian J. Ree, Yusuke Satoh, Takuya Isono, Toshifumi Satoh
    Polymer Chemistry 2021年05月 [査読有り]
     

    Three-armed cage block copolymers composed of immiscible blocks in near equivalent volume fractions formed topologically controlled sub-10 nm cylindrical and lamellar nanostructures in nanoscale films.

  • Brian J. Ree, Yusuke Satoh, Takuya Isono, Toshifumi Satoh
    Macromolecules 2021年04月19日 [査読有り]
     
    This study is the first quantitative synchrotron grazing incidence X-ray scattering investigation of nanoscale film morphologies of tricyclic block copolymers based on poly(n-decyl glycidyl ether) (PDGE) and poly(2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether) (PTEGGE) blocks in equivalent volume fractions. Both PDGE and PTEGGE blocks of the tricyclic block copolymers are amorphous, but copolymers exhibit phase-separated lamellar nanostructures due to block immiscibility. The lamellar structures vary in their structural parameters such as lamellar orientation and structural integrity stability depending on the degree of topological confinement effect taking effect. Interestingly, sub-10 nm domain spacings are established by all nanostructures, which are remarkably shorter than that of the linear analogue. These exceptionally short domain spacings are evident that the tricyclic block copolymer approach is highly efficient for developing high-performance nanolithographic materials for future advanced semiconductor applications.
  • Yoko Sakai-Otsuka, Yu Ogawa, Toshifumi Satoh, Wen Chang Chen, Redouane Borsali
    Carbohydrate Polymers 255 117528 - 117528 2021年03月01日 [査読有り]
     
    © 2020 Elsevier Ltd A carbohydrate-based fullerene derivative (AcMal7-C61) is designed, synthesized and applied to a lamellar-forming high-χ block copolymer system, poly(3-hexylthiophene)-block-peracetylated maltoheptaose (P3HT-b-AcMal7), to actualize an ordered donor/acceptor (D/A) network. A well-defined D/A lamellar structure of the P3HT-b-AcMal7:AcMal7-C61 blend with sub-10 nm domain features is achieved upon thermal annealing. The AcMal7-C61 molecules are localized in the phase-separated AcMal7 nanodomains without causing the formation of fullerene crystals while maintaining the lamellar morphology up to 1:0.5 (D:A) blending ratio. The cross-sectional TEM observation and GISAXS measurement reveals that the P3HT-b-AcMal7 tends to spontaneously organize into lamellar structures oriented perpendicular to the film surface at the air/film interface while the domain orientation at the bottom interface depends on the nature of the substrate.
  • Yu Che Chen, Yan Cheng Lin, Hui Ching Hsieh, Li Che Hsu, Wei Chen Yang, Takuya Isono, Toshifumi Satoh, Wen Chang Chen
    Journal of Materials Chemistry C 9 4 1259 - 1268 2021年01月28日 [査読有り]
     
    © The Royal Society of Chemistry 2020. We report the synthesis, morphology and photo-memory device applications of a block copolymer (BCP) consisting of poly(9,9-dioctylfluorene) (PFO) and polystyrene (PS). Three BCPs were designed with various PS contents to manipulate the structure-performance relationship of the polymer electrets in a photonic field-effect transistor-type (FET) memory device. The memory device using the BCP electret exhibited a dynamic switching behaviour with photo-writing and electrical-erasing processes. We found that the BCPs with a high PS content provided improved device performance, which could be explained by two aspects: (1) the enhanced β-conformation of the PFO strengthened the electron-trapping capability, (2) the well-dispersed and microphase-separated morphology stabilized the trapped electrons on the interface of PFO and PS domains. Consequently, PFO5k-b-PS22koutperformed in terms of the photo-responding current along with having a high current on/off ratio of 104and exhibited a retention time of more than 10 000 s. Our experimental results revealed the effectiveness of using the design based on a BCP for application in photonic FET memory devices.
  • Li Che Hsu, Takuya Isono, Yan Cheng Lin, Saburo Kobayashi, Yun Chi Chiang, Dai Hua Jiang, Chih Chien Hung, Ender Ercan, Wei Chen Yang, Hui Ching Hsieh, Kenji Tajima, Toshifumi Satoh, Wen Chang Chen
    ACS Applied Materials and Interfaces 13 2 2932 - 2943 2021年01月20日 [査読有り]
     
    © 2021 American Chemical Society. The mechanical properties and structural design flexibility of charge-trapping polymer electrets have led to their widespread use in organic field-effect transistor (OFET) memories. For example, in the electrets of polyfluorene-based conjugated/insulating block copolymers (BCPs), the confined fiberlike polyfluorene nanostructures in the insulating polymer matrix act as effective hole-trapping sites, leading to controllable memory performance through the design of BCPs. However, few studies have reported intrinsically stretchable charge-trapping materials and their memory device applications, and a practical method to correlate the thin-film morphology of BCP electrets with their charge-trapping ability has not yet been developed. In this study, a series of new conjugated/insulating BCPs, poly(9,9-di-n-hexyl-2,7-fluorene)-block-poly(δ-decanolactone)s (PF-b-PDLx, x = 1-3), as stretchable hole-trapping materials are reported. The linear and branched PDL blocks with comparable molecular weights were used to investigate the effect of polymer architecture on morphology and device performance. Moreover, the coverage area of the polyfluorene nanofibers on the BCP films was extracted from atomic force microscopy images, which can be correlated with the trapping density of the polymer electrets. The branched PDL segments not only improve stretchability but also tailor crystallinity and phase separation of the BCPs, thus increasing their charge-trapping ability. The OFET memory device with PF-b-PDL3 as the electret layer exhibited the largest memory window (102 V) and could retain its performance at up to 100% strain. This research highlights the importance of the BCP design for developing stretchable charge-trapping materials.
  • Brian J. Ree, Yoshinobu Mato, Li Xiang, Jehan Kim, Takuya Isono, Toshifumi Satoh
    Polymer Chemistry 12 5 744 - 758 2021年01月11日 

    Here we report the first quantitative investigation of nanoscale film morphologies of a cage-shaped poly(ε-caprolactone) and its counterparts in star, cyclic, and linear topologies through synchrotron grazing incidence X-ray scattering analysis.

  • Yubo Wang, Jose Enrico Q. Quinsaat, Tomoko Ono, Masatoshi Maeki, Manabu Tokeshi, Takuya Isono, Kenji Tajima, Toshifumi Satoh, Shin-ichiro Sato, Yutaka Miura, Takuya Yamamoto
    Nature Communications 11 1 6089 - 6089 2020年12月 [査読有り]
     
    AbstractNano-sized metal particles are attracting much interest in industrial and biomedical applications due to the recent progress and development of nanotechnology, and the surface-modifications by appropriate polymers are key techniques to stably express their characteristics. Herein, we applied cyclic poly(ethylene glycol) (c-PEG), having no chemical inhomogeneity, to provide a polymer topology-dependent stabilization for the surface-modification of gold nanoparticles (AuNPs) through physisorption. By simply mixing c-PEG, but not linear counterparts, enables AuNPs to maintain dispersibility through freezing, lyophilization, or heating. Surprisingly, c-PEG endowed AuNPs with even better dispersion stability than thiolated PEG (HS–PEG–OMe). The stronger affinity of c-PEG was confirmed by DLS, ζ-potential, and FT-IR. Furthermore, the c-PEG system exhibited prolonged blood circulation and enhanced tumor accumulation in mice. Our data suggests that c-PEG induces physisorption on AuNPs, supplying sufficient stability toward bio-medical applications, and would be an alternative approach to the gold–sulfur chemisorption.
  • Takuya Isono, Ryoya Komaki, Chaehun Lee, Nao Kawakami, Brian J. Ree, Kodai Watanabe, Kohei Yoshida, Hiroaki Mamiya, Takuya Yamamoto, Redouane Borsali, Kenji Tajima, Toshifumi Satoh
    Communications Chemistry 3 1 2020年12月 [査読有り][通常論文]
     
    Abstract Discrete block co-oligomers (BCOs) are gaining considerable attention due to their potential to form highly ordered ultrasmall nanostructures suitable for lithographic templates. However, laborious synthetic routes present a major hurdle to the practical application. Herein, we report a readily available discrete BCO system that is capable of forming various self-assembled nanostructures with ultrasmall periodicity. Click coupling of propargyl-functionalized sugars (containing 1–7 glucose units) and azido-functionalized terpenoids (containing 3, 4, and 9 isoprene units) afforded the discrete and monodisperse BCOs with a desired total degree of polymerization and block ratio. These BCOs microphase separated into lamellar, gyroid, and cylindrical morphologies with the domain spacing (d) of 4.2–7.5 nm. Considering easy synthesis and rich phase behavior, presented BCO systems could be highly promising for application to diverse ~4-nm nanofabrications.
  • Yoshinobu Mato, Kohei Honda, Brian J. Ree, Kenji Tajima, Takuya Yamamoto, Tetsuo Deguchi, Takuya Isono, Toshifumi Satoh
    Communications Chemistry 3 1 2020年12月01日 [査読有り][通常論文]
     
    © 2020, The Author(s). The development of precise folding techniques for synthetic polymer chains that replicate the unique structures and functions of biopolymers has long been a key challenge. In particular, spiro-type (i.e., 8-, trefoil-, and quatrefoil-shaped) polymer topologies remain challenging due to their inherent structural complexity. Herein, we establish a folding strategy to produce spiro-type multicyclic polymers via intramolecular ring-opening metathesis oligomerization of the norbornenyl groups attached at predetermined positions along a synthetic polymer precursor. This strategy provides easy access to the desired spiro-type topological polymers with a controllable number of ring units and molecular weight while retaining narrow dispersity (Ɖ < 1.1). This effective strategy marks an advancement in the development of functionalized materials composed of specific three-dimensional nanostructures.
  • Livy Laysandra, Ching-Heng Chuang, Saburo Kobayashi, Ai-Nhan Au-Duong, Yu-Hsuan Cheng, Yen-Ting Li, Maina Moses Mburu, Takuya Isono, Toshifumi Satoh, Yu-Cheng Chiu
    ACS Applied Polymer Materials 2020年11月06日 [査読有り]
  • Yoko Sakai-Otsuka, Yoshiharu Nishiyama, Jean-Luc Putaux, Martin Brinkmann, Toshifumi Satoh, Wen-Chang Chen, Redouane Borsali
    Macromolecules 2020年10月13日 [査読有り][通常論文]
  • Chiaki Hori, Tomohiro Sugiyama, Kodai Watanabe, Jian Sun, Yuu Kamada, Toshihiko Ooi, Takuya Isono, Toshifumi Satoh, Shin-ichiro Sato, Seiichi Taguchi, Ken'ichiro Matsumoto
    Polymer Degradation and Stability 179 109231 - 109231 2020年09月 [査読有り][通常論文]
     
    P[D-lactate (LA)-co-3-hydroxybutyrate (3HB)] is an artificial polyhydroxyalkanoate (PHA) containing unusual D-LA units. In this study, the P(D-LA-co-3HB)-degrading bacterial group in the soil was analyzed and the bacterial degradation of the D-LA clustering structure in the copolymer were evaluated by using chemically synthetic D-LA homo-oligomers. A total of 216 soil samples were screened on the basis of clear zone formation on agar plates containing emulsified P(64 mol% D-LA-co-3HB). The 16S rRNA analysis of the isolated bacteria resulted in the identification of eight Variovorax, three Acidovorax, and one Burkholderia strains, which are closely related to previously identified natural PHA-degrading bacteria. These bacteria nearly consumed the P(D-LA-co-3HB) emulsion in the liquid culture; however, a small amount of the D-LA fraction remained unconsumed, which should be attributable to the D-LA-clustering structure in the copolymer. Cultivation of the isolated bacteria with the D-LA homo-oligomers revealed that the oligomers with a degree of polymerization (DP) ranging from 10 to 30 were partly consumed by six Variovorax and one Acidovorax strains. In contrast, the oligomers with DP ranging from 20 to 60 were not consumed by the isolated bacteria. These results indicate that D-LA homo-oligomers with DP higher than approximately 20 are hardly degraded by the soil bacteria. Molecular dynamic simulation of the D-LA homo-oligomers indicated that the upper limit of DP is likely to be determined by the conformational structure of the oligomers in water. The information obtained in this study will be useful for the molecular design of biodegradable D-LA-containing polymers. (C) 2020 Elsevier Ltd. All rights reserved.
  • Kodai Watanabe, Satoshi Katsuhara, Hiroaki Mamiya, Yukihiko Kawamura, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    Nanoscale 12 31 16526 - 16534 2020年08月13日 [査読有り][通常論文]
     
    The highly asymmetric lamellar (A-LAM) nanostructure is one of the most important template geometries for block copolymer (BCP) lithography. However, A-LAM is unattainable from conventional BCPs, and there is no general molecular design strategy for A-LAM-forming BCP. Herein, a nanoparticle-linear hybrid BCP system is reported, which is designed based on the intramolecular crosslinking technique, as a remarkably effective platform to obtain the A-LAM morphology. The hybrid BCPs consisting of polystyrene single-chain nanoparticles and linear polylactide segments show a remarkable capability to form the A-LAM morphology in bulk, where a maximum width ratio of 4.1 between the two domains is obtained. This unusual phase behavior is attributed to the bulky and rigid characteristics of the nanoparticle block. Furthermore, the thin films of these hybrid BCPs show perpendicularly oriented A-LAM morphology on a chemically modified Si substrate, allowing promising application in the fabrication of asymmetric line-and-space nanopatterns.
  • Cihan Ozen, Toshifumi Satoh, Satoshi Maeda
    Journal of Computational Chemistry 2020年07月31日 [査読有り][通常論文]
  • Brian J. Ree, Yusuke Satoh, Takuya Isono, Toshifumi Satoh
    Nano Letters 20 9 6520 - 6525 2020年07月28日 [査読有り][通常論文]
     
    Ongoing efforts in materials science have resulted in linear block copolymer systems that generate nanostructures via the phase separation of immiscible blocks; however, such systems are limited with regard to their domain miniaturization and lack of orientation control. We overcome these limitations through the bicyclic topological alteration of a block copolymer system. Grazing incidence X-ray scattering analysis of nanoscale polymer films revealed that bicyclic topologies achieve 51.3-72.8% reductions in domain spacing when compared against their linear analogue, which is more effective than the theoretical predictions for conventional cyclic topologies. Moreover, bicyclic topologies achieve unidirectional orientation and a morphological transformation between lamellar and cylindrical domains with high structural integrity. When the near-equivalent volume fraction between the blocks is considered, the formation of hexagonally packed cylindrical domains is particularly noteworthy. Bicyclic topological alteration is therefore a powerful strategy for developing advanced nanostructured materials for microelectronics, displays, and membranes.
  • Yun‐Chi Chiang, Chih‐Chien Hung, Yan‐Cheng Lin, Yu‐Cheng Chiu, Takuya Isono, Toshifumi Satoh, Wen‐Chang Chen
    Advanced Materials 2002638 - 2002638 2020年07月23日 [査読有り][通常論文]
  • Li-Che Hsu, Saburo Kobayashi, Takuya Isono, Yun-Chi Chiang, Brian J. Ree, Toshifumi Satoh, Wen-Chang Chen
    Macromolecules 53 17 7496 - 7510 2020年07月21日 [査読有り][通常論文]
     
    In this study, poly(3-hexylthiophene)-block-poly(delta-decanolactone)s (P3HT-b-PDLs) with the molecular architecture of AB, BAB, B(2)AB(2), and B(3)AB(3) (A: P3HT, B: PDL) were synthesized for stretchable organic field-effect transistors (OFETs) through the Cu-catalyzed azido-alkyne click reaction (CuAAC) with a high yield. The effects of triblock and branched architectures on the thermal, mechanical, and electrical properties of the prepared block copolymers were studied. Block copolymer thin films prepared from the selective solvent of cyclohexane exhibited a distinct phase separating the domain of P3HT with a nanofibrillar structure. Grazing-incidence X-ray scattering results indicated that all of the block copolymer thin films possessed the P3HT crystalline domains with the same domain spacing regardless of the branched architecture. However, the branched soft segments led to a more random phase separation of the block copolymer and lower crystallinity of the P3HT block. Consequently, thin films made by the triblock copolymers with branched PDL segments (B(2)AB(2) and B(3)AB(3)) exhibited favorable electrical properties with significantly improved stretchability and smaller elastic modulus. The carrier mobility of the block copolymer-based OFETs showed a comparable performance to that of the pristine P3HT homopolymer. Also, the B(3)AB(3)-based OFET could maintain 72-75% on the charge mobility under 100% strain and 71-75% after 500 stretch-release cycles at 50% strain. The study revealed that the stretchability of the conjugated/elastic block copolymers can be significantly enhanced by our architecture design without losing their semiconducting property.
  • Muhammad Mumtaz, Yasuko Takagi, Hiroaki Mamiya, Kenji Tajima, Cécile Bouilhac, Takuya Isono, Toshifumi Satoh, Redouane Borsali
    European Polymer Journal 134 109831 - 109831 2020年07月 [査読有り][通常論文]
  • Takuya Isono, Saki Nakahira, Hui-Ching Hsieh, Satoshi Katsuhara, Hiroaki Mamiya, Takuya Yamamoto, Wen-Chang Chen, Redouane Borsali, Kenji Tajima, Toshifumi Satoh
    Macromolecules 2020年06月16日 [査読有り][通常論文]
  • Brian J. Ree, Takuya Isono, Toshifumi Satoh
    ACS Applied Materials & Interfaces 2020年06月11日 [査読有り][通常論文]
  • Tsung-Han Chuang, Yun-Chi Chiang, Hui-Ching Hsieh, Takuya Isono, Chao-Wei Huang, Redouane Borsali, Toshifumi Satoh, Wen-Chang Chen
    ACS Applied Materials & Interfaces 12 20 23217 - 23224 2020年05月20日 [査読有り][通常論文]
  • Yanli Zhou, Ruiqi Zhu, Chunhong Zhang, Xudong Liu, Zhongpeng Wang, Zhengjin Zhou, Lijia Liu, Hongxing Dong, Toshifumi Satoh, Yoshio Okamoto
    Chirality 32 5 547 - 555 2020年05月 [査読有り][通常論文]
  • Dai-Hua Jiang, Yi-Chun Liao, Chia-Jung Cho, Loganathan Veeramuthu, Fang-Cheng Liang, Ting-Chieh Wang, Chu-Chen Chueh, Toshifumi Satoh, Shih-Huang Tung, Chi-Ching Kuo
    ACS Applied Materials & Interfaces 12 12 14408 - 14415 2020年03月25日 [査読有り][通常論文]
  • Kenji Tajima, Koutaro Tahara, Junya Ohba, Ryo Kusumoto, Ryota Kose, Hiroyuki Kono, Tokuo Matsushima, Koji Fushimi, Takuya Isono, Takuya Yamamoto, Toshifumi Satoh
    Biomacromolecules 21 2 581 - 588 2020年02月10日 [査読有り][通常論文]
  • Liu, L., Wang, Y., Wang, F., Zhang, C., Zhou, Y., Zhou, Z., Liu, X., Zhu, R., Dong, H., Satoh, T.
    Reactive and Functional Polymers 146 2020年 [査読有り][通常論文]
  • Saburo Kobayashi, Kaiyu Fujiwara, Dai-Hua Jiang, Takuya Yamamoto, Kenji Tajima, Yasunori Yamamoto, Takuya Isono, Toshifumi Satoh
    Polymer Chemistry 11 42 6832 - 6839 2020年 [査読有り][通常論文]
     

    In this study, we demonstrated that the Suzuki–Miyaura catalyst transfer polycondensation (SCTP) of the triolborate-type fluorene monomer, viz. potassium 2-(7-bromo-9,9-dihexyl-9H-fluorene-2-yl)triolborate, can be an efficient and versatile approach to the precise...

  • Kaoru Takojima, Hiroshi Makino, Tatsuya Saito, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    Polymer Chemistry 11 39 6365 - 6373 2020年 [査読有り][通常論文]
     

    The alternating copolymer of lactic acid and glycolic acid (PLGA) is a highly promising next generation biodegradable material for biomedical and pharmaceutical applications due to its uniform degradation behaviors in...

  • Chi-Ho Heo, In-Gyu Bak, Chang-Geun Chae, Toshifumi Satoh, Jae-Suk Lee
    Polymer Chemistry 2020年 [査読有り][通常論文]
     

    Metal-free anionic polymerization of n-hexyl isocyanate (HIC) catalyzed by phosphazene bases in THF at −98 °C under 10−6 Torr was attempted to obtain poly(n-hexyl isocyanate) (PHIC) peptide mimics with a high purity.

  • Satoshi Katsuhara, Hiroaki Mamiya, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    Polymer Chemistry 11 17 2995 - 3002 2020年 [査読有り][通常論文]
     

    The novel high-χ BCPs comprising poly(vinyl ferrocene) and oligosaccharides formed hexagonal cylinder morphology with d values of ∼8 nm. Lamellar morphology with d values of ∼9 nm was also realized by mixing these polymers and glucose.

  • Jiang, D.-H., Kobayashi, S., Jao, C.-C., Mato, Y., Isono, T., Fang, Y.-H., Lin, C.-C., Satoh, T., Tung, S.-H., Kuo, C.-C.
    Polymers 12 1 84 - 84 2020年 [査読有り][通常論文]
  • Wu, P.-H., Lin, Y.-C., Laysandra, L., Lee, M.-H., Chiu, Y.-C., Isono, T., Satoh, T., Chen, W.-C.
    Macromolecular Rapid Communications 41 3 e1900542  2020年 [査読有り][通常論文]
  • Kaoru Takojima, Tatsuya Saito, Cedric Vevert, Viko Ladelta, Panayiotis Bilalis, Jun Watanabe, Shintaro Hatanaka, Takashi Konno, Takuya Yamamoto, Kenji Tajima, Nikos Hadjichristidis, Takuya Isono, Toshifumi Satoh
    Polymer Journal 52 1 103 - 110 2020年01月 [査読有り][通常論文]
  • Dai-Hua Jiang, Pei-Chi Chiu, Chia-Jung Cho, Loganathan Veeramuthu, Shih-Huang Tung, Toshifumi Satoh, Wei-Hung Chiang, Xingke Cai, Chi-Ching Kuo
    Nanomaterials 9 10 1383  MDPI} {AG 2019年09月 [査読有り][通常論文]
  • Brian J. Ree, Daisuke Aoki, Jehan Kim, Toshifumi Satoh, Toshikazu Takata, Moonhor Ree
    Macromolecules 52 14 5325 - 5336 2019年07月23日 [査読有り][通常論文]
  • Tatsuya Saito, Kaoru Takojima, Takafumi Oyama, Shintaro Hatanaka, Takashi Konno, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    ACS Sustainable Chemistry & Engineering 7 9 8868 - 8875 2019年05月06日 [査読有り][通常論文]
  • Zhang Chunhong, Qiu Yuan, Bo Siyuan, Wang Fuqingyun, Wang Yudan, Liu Lijia, Zhou Yanli, Niu Haijun, Dong Hongxing, Satoh Toshifumi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 57 9 1024 - 1031 2019年05月01日 [査読有り][通常論文]
  • Takafumi Oyama, Shingo Kobayashi, Tetsuo Okura, Shunsuke Sato, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    ACS Sustainable Chemistry & Engineering 7 8 7969 - 7978 American Chemical Society ({ACS}) 2019年04月15日 [査読有り][通常論文]
  • Brian J. Ree, Shingo Kobayashi, Kyuyoung Heo, Taek Joon Lee, Toshifumi Satoh, Takashi Ishizone, Moonhor Ree
    Polymer 169 225 - 233 2019年04月 [査読有り][通常論文]
     
    © 2019 In this study, we report for the first time the thin film morphology and property characteristics of a series of adamantane-containing polymers, which were investigated by using synchrotron grazing incidence X-ray scattering, X-ray reflectivity and spectroscopic ellipsometry. The chemically incorporated monomeric and dimeric adamantane units could disturb regular chain packing, ultimately producing amorphous polymers. They further tend to randomize chain orientations even in nanoscale thin films; surprisingly, random chain orientations could be achieved even for thermally-annealed thin films, which are quite different from the in-plane orientations of conventional polymer films being enhanced by thermal annealing. As a result, isotropic optical refractive indices and dielectric constants could be demonstrated even in nanoscale thin films, which are highly demanded for the production of advanced microelectronic devices. Moreover, the adamantane units incorporated into the backbone and as primary side groups could significantly reduce the dielectric constant, refractive index, critical angle, electron density and mass density of polymer. Overall, the positive impacts of incorporated adamantane units are huge on the polymer morphology and properties. All adamantane-containing polymers of this study are suitable materials for advanced microelectronics, which can replace current workhorse dielectrics, such as silicon oxide, silicon nitride, and polyimides, being used in microelectronic devices.
  • Kodai Watanabe, Satoshi Katsuhara, Hiroaki Mamiya, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    Chemical science 10 11 3330 - 3339 2019年03月21日 [査読有り][通常論文]
     
    A novel strategy for downsizing the feature of microphase-separated structures was developed via the intramolecular crosslinking reaction of block copolymers (BCPs) without changing the molecular weight. A series of BCPs consisting of poly[styrene-st-(p-3-butenyl styrene)] and poly(rac-lactide) (SBS-LA) was subjected to Ru-catalyzed olefin metathesis under highly diluted conditions to produce intramolecularly crosslinked BCPs (SBS(cl)-LAs). Small-angle X-ray scattering measurement and transmission electron microscopy observation of the SBS(cl)-LAs revealed feature size reduction in lamellar (LAM) and hexagonally close-packed cylinder (HEX) structures in the bulk state, which was surely due to the restricted chain dimensions of the intramolecularly crosslinked SBS block. Notably, the degree of size reduction was controllable by varying the crosslink density, with a maximum decrease of 22% in the LAM spacing. In addition, we successfully observed the downsizing of the HEX structure in the thin film state using atomic force microscopy, indicating the applicability of the present methodology to next-generation lithography technology.
  • Post-polymerization modification of PS-b-PMMA for achieving directed self-assembly with sub-10nm feature size
    Takuya Isono, Kohei Yoshida, Hiroaki Mamiya, Ken Miyagi, Akiyoshi Yamzaki, Toshifumi Satoh
    Proceedings of SPIE 10960 109600U-1 - 109600U-8 2019年03月 [査読無し][通常論文]
  • Dai-Hua Jiang, Ping-Chun Tsai, Chi-Ching Kuo, Fu-Cheng Jhuang, Hao-Cheng Guo, Shih-Pin Chen, Ying-Chih Liao, Toshifumi Satoh, Shih-Huang Tung
    ACS Applied Materials & Interfaces American Chemical Society ({ACS}) 2019年03月 [査読有り][通常論文]
  • Yoshinobu Mato, Kohei Honda, Kenji Tajima, Takuya Yamamoto, Takuya Isono, Toshifumi Satoh
    Chemical science 10 2 440 - 446 2019年01月14日 [査読有り][通常論文]
     
    Cage-shaped polymers, or "macromolecular cages", are of great interest as the macromolecular analogues of molecular cages because of their various potential applications in supramolecular chemistry and materials science. However, the systematic synthesis of macromolecular cages remains a great challenge. Herein, we describe a robust and versatile synthetic strategy for macromolecular cages with defined arm numbers and sizes based on the intramolecular consecutive cyclization of highly reactive norbornene groups attached to each end of the arms of a star-shaped polymer precursor. The cyclizations of three-, four-, six-, and eight-armed star-shaped poly(ε-caprolactone)s (PCLs) bearing a norbornenyl group at each arm terminus were effected with Grubbs' third generation catalyst at high dilution. 1H NMR, SEC, and MALDI-TOF MS analyses revealed that the reaction proceeded to produce the desired macromolecular cages with sufficient purity. The molecular sizes of the macromolecular cages were controlled by simply changing the molecular weight of the star-shaped polymer precursors. Systematic investigation of the structure-property relationships confirmed that the macromolecular cages adopt a much more compact conformation, in both the solution and bulk states, as compared to their linear and star-shaped counterparts. This synthetic approach marks a significant advance in the synthesis of complex macromolecular architectures and provides a platform for novel applications using cage-shaped molecules with polymer frameworks.
  • Jiang, D.-H., Tsai, Y.-H., Veeramuthu, L., Liang, F.-C., Chen, L.-C., Lin, C.C., Satoh, T., Tung, S.-H., Kuo, C.-C.
    APL Materials 7 11 2019年 [査読有り][通常論文]
  • Chiang, Y.-C., Kobayashi, S., Isono, T., Shih, C.-C., Shingu, T., Hung, C.-C., Hsieh, H.-C., Tung, S.-H., Satoh, T., Chen, W.-C.
    Polymer Chemistry 10 40 2019年 [査読有り][通常論文]
  • 齋藤達也, 磯野拓也, 佐藤敏文
    触媒 61 3 150‐156  2019年 [査読無し][通常論文]
  • Kohei Yoshida, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    Polymer Chemistry Royal Society of Chemistry ({RSC}) 2019年 [査読有り][通常論文]
  • Yanli Zhou, Chunhong Zhang, Zhengjin Zhou, Ruiqi Zhu, Lijia Liu, Jianwei Bai, Hongxing Dong, Toshifumi Satoh, Yoshio Okamoto
    Polymer Chemistry Royal Society of Chemistry ({RSC}) 2019年 [査読有り][通常論文]
  • Yanli Zhou, Chunhong Zhang, Rui Ma, Lijia Liu, Hongxing Dong, Toshifumi Satoh, Yoshio Okamoto
    New Journal of Chemistry 43 8 3439  Royal Society of Chemistry ({RSC}) 2019年 [査読有り][通常論文]
  • Brian J. Ree, Toshifumi Satoh, Takuya Yamamoto
    Polymers 11 1 163/161 - 163/116 2019年01月 [査読有り][通常論文]
     
    In this study, we investigate structures and stabilities of the micelles of a cyclic amphiphile (c-PBA-b-PEO) composed of poly(n-butyl acrylate) (PBA) and poly(ethylene oxide) (PEO) blocks and its linear diblock and triblock analogues (l-PBA-b-PEO and l-PBA-b-PEO-b-PBA) by using synchrotron X-ray scattering and quantitative data analysis. The comprehensive scattering analysis gives details and insights to the micellar architecture through structural parameters. Furthermore, this analysis provides direct clues for structural stabilities in micelles, which can be used as a good guideline to design highly stable micelles. Interestingly, in water, all topological polymers are found to form ellipsoidal micelles rather than spherical micelles; more interestingly, the cyclic polymer and its linear triblock analog make oblate-ellipsoidal micelles while the linear diblock analog makes a prolate-ellipsoidal micelle. The analysis results collectively inform that the cyclic topology enables more compact micelle formation as well as provides a positive impact on the micellar structural integrity.
  • Takuya Isono, Nao Kawakami, Kodai Watanabe, Kohei Yoshida, Issei Otsuka, Hiroaki Mamiya, Hajime Ito, Takuya Yamamoto, Kenji Tajima, Redouane Borsali, Toshifumi Satoh
    Polymer Chemistry Royal Society of Chemistry ({RSC}) 2019年 [査読有り][通常論文]
  • Tatsuya Fukushima, Hirotaka Ishibashi, Daichi Suemasa, Ryosuke Nakamura, Ryosuke Nakamura, Ryosuke Nakamura, Masanobu Yomogida, Takuya Isono, Toshifumi Satoh, Hironori Kaji
    Journal of Polymer Science Part B: Polymer Physics 57 5 266 - 271 Wiley 2019年01月 [査読有り][通常論文]
  • Ree, B.J., Aoki, D., Kim, J., Satoh, T., Takata, T., Ree, M.
    Macromolecular Rapid Communications 40 21 2019年 [査読有り][通常論文]
  • Brian J. Ree, Jongchan Lee, Yusuke Satoh, Kyungho Kwon, Takuya Isono, Toshifumi Satoh, Moonhor Ree
    Polymers 10 12 2018年12月 [査読有り][通常論文]
     
    Micelles were prepared in organic solvents by using three topological polymer amphiphiles: (i) cyclic poly(n-decyl glycidyl ether-block-2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether) (c-PDGE-b-PTEGGE) and (ii) its linear analogue (l-PDGE-b-PTEGGE); (iii) linear poly(6-phosphorylcholinehexylthiopropyl glycidyl ether-block-n-dodecanoyl glycidyl ether) (l-PPCGE-b-PDDGE). For the individual micelle solutions, the size and distribution were determined by dynamic light scattering (DLS) and synchrotron X-ray scattering analyses. The synchrotron X-ray scattering analysis further found that c-PDGE-b-PTEGGE forms oblate ellipsoidal micelle in an ethanol/water mixture, l-PDGE-b-PTEGGE makes prolate ellipsoidal micelle in an ethanol/water mixture, and l-PPCGE-b-PDDGE forms cylindrical micelle in chloroform. This comparative study found that there are large differences in the size and distribution results extracted by DLS and X-ray scattering analyses. All possible factors to cause such large differences are discussed. Moreover, a better use of the DLS instrument with keeping its merits is proposed.
  • Chen, B.-Y, Lung, Y.-C., Kuo, C.-C., Liang, F.-C, Tsai, T.-L, Jiang, D.-H, Satoh, T, Jeng, R.-J
    Polymers 10 11 1259/1251 - 1259/1216 2018年11月 [査読有り][通常論文]
  • Takuya Yamamoto, Masaaki Hosokawa, Minato Nakamura, Shin-ichiro Sato, Takuya Isono, Kenji Tajima, Toshifumi Satoh, Masamichi Sato, Yasuyuki Tezuka, Akinori Saeki, Yoshihiro Kikkawa
    Macromolecules American Chemical Society ({ACS}) 2018年11月 [査読有り][通常論文]
  • Kohei Yoshida, Lin Tian, Ken Miyagi, Akiyoshi Yamazaki, Hiroaki Mamiya, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    Macromolecules 51 20 8064  American Chemical Society ({ACS}) 2018年10月 [査読有り][通常論文]
  • Kohei Yoshida, Shunma Tanaka, Takuya Yamamoto, Kenji Tajima, Redouane Borsali, Takuya Isono, Toshifumi Satoh
    Macromolecules American Chemical Society ({ACS}) 2018年10月 [査読有り][通常論文]
  • Shingu Tomoki, Yamamoto Takuya, Tajima Kenji, Isono Takuya, Satoh Toshifumi
    Polymers 10 8 2018年08月06日 [査読有り][通常論文]
     
    Cyclic polymers exhibit unique physical and chemical properties because of the restricted chain mobility and absence of chain ends. Although many types of homopolymers and diblock copolymers possessing cyclic architectures have been synthesized to date, there are relatively few reports of cyclic triblock terpolymers because of their synthetic difficulties. In this study, a novel synthetic approach for μ-ABC tricyclic miktoarm star polymers involving t-Bu-P₄-catalyzed ring-opening polymerization (ROP) of glycidyl ethers and intramolecular copper-catalyzed azido-alkyne cycloaddition (CuAAC) was developed. First, the t-Bu-P₄-catalyzed ROP of decyl glycidyl ether, dec-9-enyl glycidyl ether, and 2-(2-(2-methoxyethoxy) ethoxy) ethyl glycidyl ether with the aid of functional initiators and terminators was employed for the preparation of a clickable linear triblock terpolymer precursor possessing three azido and three ethynyl groups at the selected positions. Next, the intramolecular CuAAC of the linear precursor successfully produced the well-defined tricyclic triblock terpolymer with narrow dispersity in a reasonable yield. The present strategy is useful for synthesizing model polymers for studying the topological effects on the triblock terpolymer self-assembly.
  • Hsieh Hui-Ching, Hung Chih-Chien, Watanabe Kodai, Chen Jung-Yao, Chiu Yu-Cheng, Isono Takuya, Chiang Yun-Chi, Reghu Renji R, Satoh Toshifumi, Chen Wen-Chang
    POLYMER CHEMISTRY 9 27 3820 - 3831 2018年07月21日 [査読有り][通常論文]
  • Hung Chih-Chien, Nakahira Saki, Chiu Yu-Cheng, Isono Takuya, Wu Hun-Chin, Watanabe Kodai, Chiang Yun-Chi, Takashima Shoichi, Borsali Redouane, Tung Shih-Huang, Satoh Toshifumi, Chen Wen-Chang
    MACROMOLECULES 51 13 4966 - 4975 2018年07月10日 [査読有り][通常論文]
  • Takuya Isono, Tetsuya Sasamori, Kohei Honda, Yoshinobu Mato, Takuya Yamamoto, Kenji Tajima, Toshifumi Satoh
    Macromolecules 51 10 3855 - 3864 American Chemical Society ({ACS}) 2018年05月22日 [査読有り][通常論文]
     
    A novel synthesis of multicyclic polymers that feature ultradense arrays of cyclic polymer units has been developed by exploiting the cyclopolymerization of α,ω-norbornenyl end-functionalized macromonomers mediated by the Grubbs third-generation catalyst (G3). Owing to the living polymerization nature, the number of cyclic repeating units in these multicyclic polymers was controlled to be between 1 and approximately 70 by varying the initial macromonomer-to-G3 ratio. The ring size was also tuned by choosing the molecular weight of the macromonomer in this way we successfully prepared multicyclic polymers that possess cyclic repeating units composed of up to about 500 atoms, which by far exceeds those prepared to date by cyclopolymerization. Specifically, cyclopolymerizations of α,ω-norbornenyl end-functionalized poly(l-lactide)s (PLLAs) proceeded homogeneously under highly dilute conditions (∼0.1 mM in CH2Cl2) to give multicyclic polymers that feature cyclic PLLA repeating units on the polynorbornene backbone. The cyclic product architectures were confirmed not only by structural characterization based on NMR, MALDI-TOF MS, and SEC analyses but also by comparing their glass transition temperatures, viscosities, and hydrodynamic radii with their acyclic counterparts. The cyclopolymerization strategy was applicable to a variety of α,ω-norbornenyl end-functionalized macromonomers, such as poly(ϵ-caprolactone), poly(ethylene glycol) (PEG), poly(tetrahydrofuran), and PLLA-b-PEG-b-PLLA. The successful statistical and block cyclocopolymerizations of the PLLA and PEG macromonomers gave amphiphilic multicyclic copolymers.
  • Takuya Isono, Hoyeol Lee, Kana Miyachi, Yusuke Satoh, Toyoji Kakuchi, Moonhor Ree, Toshifumi Satoh
    Macromolecules 51 8 2939 - 2950 2018年04月24日 [査読有り][通常論文]
     
    A series of brush block copolymers (BBCPs) consisting of poly(decyl glycidyl ether) (PDGE) and poly(10-hydroxyldecyl glycidyl ether) (PHDGE) blocks, having four different types of chain tacticities, i.e., [at-PDGE]-b-[at-PDEGE], [at-PDGE]-b-[it-PDEGE], [it-PDGE]-b-[at-PDEGE], and [it-PDGE]-b-[it-PDEGE], where the it and at represent the isotactic and atactic chains, respectively, were prepared by t-Bu-P4-catalyzed sequential anionic ring-opening polymerization of glycidyl ethers followed by side-chain modification. The corresponding homopolymers, i.e., at-PDGE, it-PDGE, at-PHDGE, and it-PHDGE, were also prepared for comparison with the BBCPs. The PDGE homopolymers were significantly promoted in the phase transitions and morphological structure formation by the isotacticity formation. In particular, it-PDGE was found to form only a horizontal multibilayer structure with a monoclinic lattice in thin films, which was driven by the bristles' self-assembling ability and enhanced by the isotacticity. However, the PHDGE homopolymers were found to reveal somewhat different behaviors in the phase transitions and morphological structure formation by the tacticity control due to the additional presence of a hydroxyl group in the bristle end as an H-bonding interaction site. The H-bonding interaction could be enhanced by the isotacticity formation. The it-PHDGE homopolymer formed only the horizontal multibilayer structure, which was different from the formation of a mixture of horizontal and tilted multibilayer structures in at-PHDGE. The structural characteristics were further significantly influenced by the diblock formation and the tacticity of the counterpart block. Because of the strong self-assembling characteristics of the individual block components, all the BBCPs formed separate crystals rather than cocrystals. The isotacticity always promoted the formation of better quality morphological structures in terms of their lateral ordering and orientation.
  • Boram Kim, Chang-Geun Chae, Yusuke Satoh, Takuya Isono, Min-Kyoon Ahn, Cheong-Min Min, Jin-Hyeok Hong, Carolina Frias Ramirez, Toshifumi Satoh, Jae-Suk Lee
    Macromolecules 51 6 2293 - 2301 American Chemical Society ({ACS}) 2018年03月27日 [査読有り][通常論文]
     
    Hard-soft-hard triblock copolymers based on poly(ethylene oxide) (PEO), poly(2-naphthyl glycidyl ether)-block-poly[2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether]-block-poly(2-naphthyl glycidyl ether)s (PNG-PTG-PNGs), were synthesized by sequential ring-opening polymerization of 2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether and 2-naphthyl glycidyl ether using a bidirectional initiator catalyzed by a phosphazene base. Four PNG-PTG-PNGs had different block compositions (fwt,PNG = 9.2-28.6 wt %), controlled molecular weights (Mn = 23.9-30.9 kDa), and narrow dispersities (Crossed D sign = 1.11-1.14). Most of the PNG-PTG-PNG electrolytes had much higher Li+ conductivities than that of a PEO electrolyte (6.54 × 10-7 S cm-1) at room temperature. Eespecially, the Li+ conductivity of PNG18-PTG107-PNG18 electrolyte (9.5 × 10-5 S cm-1 for fwt,PNG = 28.6 wt %) was comparable to one of a PTG electrolyte (1.11 × 10-4 S cm-1). The Li+ conductivities of PNG-PTG-PNG electrolytes were closely correlated to efficient Li+ transport channels formed by the microphase separation into soft PTG and hard PNG domains.
  • Tatsuya Saito, Yusuke Aizawa, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    Macromolecules 51 3 689 - 696 2018年02月13日 [査読有り][通常論文]
     
    Alkali metal carboxylates were discovered as efficient and simple catalysts for the ring-opening polymerization of cyclic esters that are alternatives to conventional metal-based catalysts and organocatalysts. In our system using an alcohol initiator and this simple catalyst, biodegradable and biocompatible aliphatic polyesters, such as poly(lactide), poly(e-caprolactone), poly(δ-valerolactone), and poly(trimethylene carbonate), were obtained with predictive molecular weights ranging from 3500 to 22-600 and narrow dispersities. A kinetic experiment for the ROP of l-lactide confirmed the controlled/living nature of the present ROP system, which allowed the precise synthesis of end-functionalized polyesters as well as multihydroxyl-containing polyesters, including α,hydroxy telechelic and star-shaped polyesters. Furthermore, a block copolymer containing the poly(l-lactide) segment was successfully synthesized using a macroinitiator possessing a hydroxyl group at the chain end. The tunability of the alkali metal carboxylates by the appropriate choice of the alkyl moiety and countercation enables not only control of the polymerization behavior but also expansion of the scope of the applicable monomers. Given the low cost, easy handling, and low toxicity of the alkali metal carboxylates, the present ROP system can be highly promising for both laboratory- and industrial-scale polyester productions.
  • Ken'Ichiro Matsumoto, Chiaki Hori, Ryunosuke Fujii, Masahiro Takaya, Takashi Ooba, Toshihiko Ooi, Takuya Isono, Toshifumi Satoh, Seiichi Taguchi
    Biomacromolecules 19 2 662 - 671 2018年02月12日 [査読有り][通常論文]
     
    Biological polymer synthetic systems, which utilize no template molecules, normally synthesize random copolymers. We report an exception, a synthesis of block polyhydroxyalkanoates (PHAs) in an engineered Escherichia coli. Using an engineered PHA synthase, block copolymers poly[(R)-2-hydroxybutyrate(2HB)-b-(R)-3-hydroxybutyrate(3HB)] were produced in E. coli. The covalent linkage between P(2HB) and P(3HB) segments was verified with solvent fractionation and microphase separation. Notably, the block sequence was generated under the simultaneous consumption of two monomer precursors, indicating the existence of a rapid monomer switching mechanism during polymerization. Based on in vivo metabolic intermediate analysis and the relevant in vitro enzymatic activities, we propose a model in which the rapid intracellular 3HB-CoA fluctuation during polymer synthesis is a major factor in generating block sequences. The dynamic change of intracellular monomer levels is a novel regulatory principle of monomer sequences of biopolymers.
  • Chun Che Lin, Dai-Hua Jiang, Chi-Ching Kuo, Chia-Jung Cho, Yi-Hsuan Tsai, Toshifumi Satoh, Chaochin Su
    ACS Applied Materials and Interfaces 10 3 2210 - 2215 2018年01月24日 [査読有り][通常論文]
     
    Cesium lead halide perovskite nanocrystals (NCs) with excellent intrinsic properties have been employed universally in optoelectronic applications but undergo hydrolysis even when exposed to atmospheric moisture. In the present study, composite CsPbX3 (X = Cl, Br, and I) perovskite NCs were encapsulated with stretchable (poly(styrene-butadiene-styrene) SBS) fibers by electrospinning to prepare water-resistant hybrid membranes as multicolor optical active layers. Brightly luminescent and color-tunable hydrophobic fiber membranes (FMs) with perovskite NCs were maintained for longer than 1 h in water. A unique remote FMs packaging approach was used in high-brightness perovskite light-emitting diodes (PeLEDs) for the first time.
  • Takuya Isono, Brian J. Ree, Kenji Tajima, Redouane Borsali, Toshifumi Satoh
    Macromolecules 51 2 428 - 437 2018年01月23日 [査読有り][通常論文]
     
    Microphase-separated structures of block copolymers (BCPs) have attracted considerable attention for their potential application in the bottom-up fabrication of 10 nm scale nanostructured materials. To realize sustainable development within this field, the creation of novel BCP materials from renewable biomass resources is of fundamental interest. Thus, we herein focused on maltoheptaose-b-poly(δ-decanolactone)-b-maltoheptaose (MH-b-PDL-b-MH) as a sustainable alternative for nanostructure-forming BCPs, in which both constitutional blocks can be derived from renewable biomass resources, in the case, δ-decanolactone and amylose. Well-defined MH-b-PDL-b-MHs with varying PDL lengths were synthesized through a combination of controlled/living ring-opening polymerization and the click reaction. The prepared MH-b-PDL-b-MHs successfully self-assembled into highly ordered hexagonal cylindrical structures with a domain-spacing of ∼12-14 nm in both the bulk and thin film states. Interestingly, the as-cast thin films of MH-b-PDL-b-MHs (with PDL lengths of 9K and 13K) form horizontal cylinders, with thermal annealing (180 °C, 30 min) resulting in a drastic change in the domain orientation from horizontal to vertical. Thus, the results presented herein demonstrated that the combination of oligosaccharides and biomass-derived hydrophobic polymers appears promising for the sustainable development of nanotechnology and related fields.
  • 磯野拓也, 佐藤敏文
    CSJ Current Review 29 58‐68,1(1)  2018年 [査読無し][通常論文]
  • Brian J. Ree, Yusuke Satoh, Kyeong Sik Jin, Takuya Isono, Won Jong Kim, Toyoji Kakuchi, Toshifumi Satoh, Moonhor Ree
    NPG ASIA MATERIALS 9 2017年12月 [査読有り][通常論文]
     
    This study reports the first well-defined and stable nanomicelles (20 - 30 nm in diameter) self-assembled from amphiphilic brush (comb-like) cyclic and tadpole-shaped copolymers composed of hydrophobic n-decyl and hydrophilic 2-(2-methoxyethoxy)ethoxy) ethyl bristle blocks based on a poly(glycidyl ether) backbone. The micelle formation behaviour and structural details were investigated by synchrotron X-ray scattering analysis in a rigorous and complementary manner. The amphiphilic brush cyclic topology facilitates more compact and stable aggregation behaviour in the micelle core and a more densely packed corona, which prevents intermicellar aggregation. The presence of a hydrophobic component with brush cyclic topology inside the core is identified as the primary micelle stabilizing factor, enabling stable core aggregation and sharper core-corona interface formation. The presence of a hydrophilic brush cyclic component in the corona is determined as the secondary micelle stabilizing factor, helping nullify the corona penetration by polymer chains from other micelles and ultimately prevent the intermicellar aggregation-mediated collapse of the micellar structure. Overall, the brush cyclic topology was confirmed to be beneficial for forming highly stable nanomicelles with an extremely narrow (pseudo-monodisperse) size distribution compared with conventional linear topology and tadpole topologies. All the results of this study provide a unique opportunity for designing advanced functional high-performance amphiphilic materials for nanomicelles that are unattainable by other conventional methods and broadening their applications in various fields, including drug delivery, biomedical imaging, foods, cosmetics, smart coatings, photonics and molecular electronics.
  • Yanli Zhou, Chunhong Zhang, Qianqian Geng, Lijia Liu, Hongxing Dong, Toshifumi Satoh, Yoshio Okamoto
    POLYMER 131 17 - 24 2017年11月 [査読有り][通常論文]
     
    Novel one-handed helical copoly(phenylacetylene)s bearing a small amount of 3-(triethoxysilyl)propyl residues (CPAs 1-4) were synthesized, and efficiently chemically immobilized onto silica gel by the intermolecular polycondensation of the triethoxysilyl groups. Their chiral recognition abilities were evaluated as immobilized-type chiral stationary phases (CSPs) for high performance liquid chromatography (HPLC). These immobilized-type CSPs showed different chiral recognition abilities from the corresponding coated-type CSPs, which may be ascribed to the conformational change in the copoly(phenylacetylene)s during the immobilization process according to the diffuse reflectance circular dichroism (DRCD) measurement of the copolymer. In addition, the immobilized-type CSPs showed a universal solvent tolerability, for instance, CHCl3-containing eluents that cannot be used with the corresponding coated-type CSPs could now be used for the immobilized-type CSPs so that the chiral recognition of i-CSP-2 for the racemic 1-(9-anthyl)-2,2,2-trifluoroethanol (5) was improved with separation factors comparable or higher than those obtained on the popular polysaccharide-based CSPs. The intermolecular polycondensation of the triethoxysilyl groups of the copoly(phenylacetylene)s is a valuable immobilization method for poly(phenylacetylene)-based CSPs. (C) 2017 Published by Elsevier Ltd.
  • Takuya Isono, Kana Miyachi, Yusuke Satoh, Shin-ichiro Sato, Toyoji Kakuchi, Toshifumi Satoh
    POLYMER CHEMISTRY 8 37 5698 - 5707 2017年10月 [査読有り][通常論文]
     
    This paper describes a comprehensive study of the lower critical solution temperature (LCST)-type thermoresponsive properties of various poly(glycidyl ether) homopolymers with a varying side chain structure, molecular weight, and main chain tacticity, as well as their copolymers with a varying monomer composition and monomer sequence. For the initial screening, we prepared nine kinds of poly(glycidyl ether)s by the phosphazene base-catalyzed ring-opening polymerization of glycidyl methyl ether (MeGE), ethyl glycidyl ether (EtGE), glycidyl isopropyl ether (iPrGE), 2-methoxyethyl glycidyl ether (MeEOGE), 2-ethoxyethyl glycidyl ether (EtEOGE), 2-propoxyethyl glycidyl ether (PrEOGE), 2-(2- methoxyethoxy) ethyl glycidyl ether (MeEO(2)GE), 2-(2-ethoxyethyl) ethyl glycidyl ether (EtEO(2)GE), and 2-(2-(2-methoxyethoxy) ethoxy) ethyl glycidyl ether (MeEO(3)GE). Among them, poly(MeGE), poly(EtGE), poly(MeEOGE), poly(EtEOGE), and poly(MeEO(2)GE) (M-n = ca. 5000 g mol(-1)) were found to exhibit a LCST-type phase transition in water at 65.5 degrees C, 10.3 degrees C, 91.6 degrees C, 41.3 degrees C, and 58.2 degrees C, respectively. Although the molecular weight and main chain tacticity had little impact on the phase transition temperature, the side chain structure, i.e., the number of oxyethylene units and terminal alkyl groups, significantly affected the transition temperature. The statistical copolymers composed of MeEOGE and EtEOGE revealed that the transition temperature of the polymer can be desirably customized in between those of the homopolymers by varying the monomer composition. On the other hand, we found that the block copolymer composed of MeEOGE and EtEOGE exhibited a complex thermoresponsive behavior due to its ability to form a micellar aggregate.
  • Kenji Tajima, Ryo Kusumoto, Ryota Kose, Hiroyuki Kono, Tokuo Matsushima, Takuya Isono, Takuya Yamamoto, Toshifumi Satoh
    BIOMACROMOLECULES 18 10 3432 - 3438 2017年10月 [査読有り][通常論文]
     
    Nanofibrillated bacterial cellulose (NFBC) is produced by culturing a cellulose-producing bacterium (Gluconacetobacter intermedius NEDO-01) with rotation or agitation in medium supplemented with carboxymethylcellulose (CMC). Despite a high yield and dispersibility in water, the product immediately aggregates in organic solvents. To broaden its applicability, we prepared amphiphilic NFBC by culturing strain NEDO-01 in medium supplemented with hydroxyethylcellulose or hydroxypropylcellulose instead of CMC. Transmission electron microscopy analysis revealed that the resultant materials (HE-NFBC and HP-NFBC, respectively) comprised relatively uniform fibers with 'diameters of 33 +/- 7 and 42 +/- 8 nm, respectively. HP-NFBC was dispersible in polar organic solvents such as methanol, acetone, isopropyl alcohol, acetonitrile, tetrahydrofuran (THF), and dimethylformamide, and was also dispersible in poly(methyl methacrylate) (PMMA) by solvent mixing using THF. HP-NFBC/PMMA composite films were highly transparent and had a higher tensile strength than neat PMMA film. Thus, HP-NFBC has a broad range of applications, including as a filler material.
  • Guihua Cui, Dehai Zhao, Peng Lv, Zhengguo Gao, Shuiying Chen, Nannan Qiu, Toshifumi Satoh, Toyoji Kakuchi, Qian Duan
    OPTICAL MATERIALS 72 115 - 121 2017年10月 [査読有り][通常論文]
     
    A series of novel fluorescent complexes was formed by chelation of the thermosensitive polymers with europium(III) ions. The polymers was synthesized via atom transfer radical polymerization (ATRP), which composed of poly(N-isopropyl acrylamide) (PNIPAM) and 2-amino-2-deoxy-D-glucopyranose(D-glucosamine, GA). The aqueous solutions of the polymers and its Eu(III) complexes exhibited a lower critical solution temperatures (LCSTs), and which were approximately equal to body temperature. The maximum emission intensity of the complexes at 613 nm was enhanced by a factor of approximately 10 relative to that of the corresponding Eu(III) chloride. Cell viability assays suggested that these thermosensitive polymers and Eu(III) complexes showed excellent biocompatibility in vitro. (C) 2017 Elsevier B.V. All rights reserved.
  • 齋藤 達也, 磯野 拓也, 佐藤 敏文
    化學工業 68 9 643 - 651 小峰工業出版 2017年09月 [査読無し][通常論文]
  • Camila Utsunomia, Tatsuya Saito, Ken'ichiro Matsumoto, Chiaki Hori, Takuya Isono, Toshifumi Satoh, Seiichi Taguchi
    JOURNAL OF POLYMER RESEARCH 24 10 2017年09月 [査読有り][通常論文]
     
    D-Lactate (LA)-based oligomers (D-LAOs), consisting of D-LA and D-3-hydroxybutyrate (D-3HB), are biobased compounds which are produced and spontaneously secreted by recombinant Escherichia coli. By supplementing the bacterial cultivation with diethylene glycol (DEG), the oligomers featuring hydroxyl groups at both ends of their structures, the D-LAOs-DEG, can be efficiently biosynthesized. In the present work, we attempted to verify the feasibility of D-LAOs-DEG as building blocks to be assembled into LA-based poly(ester-urethane) via polyaddition reactionwith diisocyanate. The polymeric products were demonstrated by SEC and the urethane bound formation in the polymer was determined by FT-IR analysis, indicating that the polymerization was successfully performed. These results suggested that the one-step biosynthesized D-LAOs-DEG are potential substrates for the synthesis of LA-based poly(ester-urethane) and can be further applied to the synthesis of other LA copolymers.
  • Guihua Cui, Yu Bai, Wenliang Li, Zhengguo Gao, Shuiying Chen, Nannan Qiu, Toshifumi Satoh, Toyoji Kakuchi, Qian Duan
    MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS 78 603 - 608 2017年09月 [査読有り][通常論文]
     
    A series of chain-end functional polymers composed of poly(N-isopropylacrylamide) (PNIPAM) and 2-amino-2deoxy-D-glucopyranose(D-glucosamine, GA) was synthesized via atom transfer radical polymerization (ATRP). Novel fluorescent complexes of glucosamine-PNI-PAM/Eu(III) were then formed by chelation of the polymers and europium(III) ions. The aqueous solutions of the polymers and its Eu(III) complexes exhibited a lower critical solution temperatures (LCSTs), and which were approximately equal to body temperature. Cell viability assays suggested that these thermosensitive polymers and Eu(III) complexes showed excellent biocompatibility in vitro. (C) 2017 Published by Elsevier B.V.
  • Ryoto Tanaka, Kodai Watanabe, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    POLYMER CHEMISTRY 8 23 3647 - 3656 2017年06月 [査読有り][通常論文]
     
    The effect of intramolecular cross-linking in an amphiphilic block copolymer (BCP) system was systematically investigated in terms of its thermal properties, critical micelle concentration (CMC), and aqueous self-assembly. A series of linear BCPs consisting of poly(ethylene glycol) (PEG) as a hydrophilic block and poly(epsilon-caprolactone-co-7-allyloxepan-2-one) (P(CL-co-ACL)) as a hydrophobic block were prepared by the ring-opening copolymerization of epsilon-caprolactone (CL) and 7-allyloxepan-2-one (ACL) using poly (ethylene glycol) monomethyl ether as an initiator. The intramolecular olefin metathesis reaction in the P(CL-co-ACL) block was subsequently carried out under various conditions to prepare the cross-linked BCPs with different degrees of cross-linking. The thermal analysis confirmed that the linear P(CL-co-ACL) block was found to crystallize, while the cross-linked one showed no crystallinity. In addition, glass transition temperature of the P(CL-co-ACL) block increased upon cross-linking. On the other hand, the intramolecular cross-linking had no significant influence on the CMC. The self-assembled micelles were prepared from the obtained BCPs and their size and morphology were investigated. For the BCPs with relatively short PEG chains, the micellar size decreased from 36.6 nm to 16.7 nm as the degree of cross-linking of the P(CL-co-ACL) block increased. On the other hand, the BCPs with relatively long PEG chains showed a change in the micellar morphology from spherical micelles to short worm and large compound micelles upon cross-linking.
  • 磯野 拓也, 佐藤 敏文
    高分子 = High polymers, Japan : polymers 66 5 214 - 216 高分子学会 2017年05月 [査読無し][通常論文]
  • Jau-Tzeng Wang, Shoichi Takshima, Hung-Chin Wu, Chien-Chung Shih, Takuya Isono, Toyoji Kakuchi, Toshifumi Satoh, Wen-Chang Chen
    MACROMOLECULES 50 4 1442 - 1452 2017年02月 [査読有り][通常論文]
     
    We report the synthesis, morphology, and properties of poly(3-hexylthiophene)-block-poly(butyl acrylate) (P3HT-b-PBA) for stretchable electronics applications, which are consisted of semiconducting P3HT and low glass transistion temperature (T-g) PBA blocks. The P3HT-b-PBA thin films self-assembled into fibrillar-like nanostructures and maintained the edge-on oreientation even at a low P3HT composition, based on the results from atomic force microscopy (AFM) and grazing incidence X-ray diffraction (GIRD). By varying the P3HT/PBA ratio, the tensile modulus decreased as the block length of PBA increased, from 0.93 GPa for P3HT to 0.19 GPa for P3HT-b-PBA(12k). The field effect transistor (FET) using P3HT-b-PBA as the active layer exhibited a high p-type mobility over 10(-2) cm(2) indicating its good charge transporting ability. Furthermore, the P3HT-b-PBA(6k) based FET under 100% strain had a high mobility of 2.5 X 10(-2) cm(2) V-1 s(-1) with an on/off ratio of 7.2 X 10(6), and it maintained over 10(-2) cm(2) V-1 s(-1) for 1000 cycles, suggesting the promising stability and reproducbility. The result demonstrated that the newly designed conjugated rod coil block copolymers could have potential applications in stretchable electronic devices.
  • Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER REVIEWS 57 1 159 - 174 2017年 [査読有り][通常論文]
     
    This review describes the recent progress in the design and fabrication of polyacetylene-based chemosensors applicable to colorimetric and fluorescence anion sensing that has been increasingly demanded in diverse fields. The validity of polyacetylene derivatives as an anion sensor material has been demonstrated based on the evaluation of the anion-induced optical responses for various types of polyacetylenes with different binding sites and pendant structures. Suitable molecular designs of the polyacetylene have been found to exert a beneficial influence on the anion detection abilities, which are specifically highlighted in this review article.
  • Yusuke Satoh, Hirohiko Matsuno, Takuya Yamamoto, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    MACROMOLECULES 50 1 97 - 106 2017年01月 [査読有り][通常論文]
     
    This paper describes a novel synthetic approach for three- and four-armed cage-shaped polymers based on the topological conversion of the corresponding trefoil- and quatrefoil-shaped precursors. The trefoil- and quatrefoil-shaped polymers were synthesized by the following three reaction steps: (1) the t-Bu-P-4-catalyzed ring-opening polymerization of butylene oxide using multiple hydroxy- and azido-functionalized initiators to produce the three- or four-armed star-shaped polymers possessing three or four azido groups at the focal point, respectively, (2) the omega-end modification to install a propargyl group at each chain end, and (3) the intramolecular multiple click cyclization of the clickable star-shaped precursors. The topological conversion from the trefoil- and quatrefoil-shaped polymers to the cage-shaped polymers was achieved by the catalytic hydrogenolysis of the benzyl ether linkages that had been installed at the focal point. The amphiphilic cage-shaped block copolymers together with the corresponding trefoil- and quatrefoil-shaped counterparts were synthesized in a similar way using 2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether as a hydrophilic monomer and decyl glycidyl ether as a hydrophobic monomer. Interestingly, significant changes in the critical micelle concentration and micellar morphology were observed for the amphiphilic block copolymers upon the topological conversion from the trefoil- and quatrefoil-shaped to cage-shaped architectures.
  • 磯野拓也, 佐藤敏文
    高分子 66 5 214‐216  2017年 [査読無し][通常論文]
  • 齋藤達也, 齋藤達也, 磯野拓也, 佐藤敏文
    化学工業 68 9 643‐651  2017年 [査読無し][通常論文]
  • Kenji Tajima, Xuerong Han, Yoshiki Hashimoto, Yasuharu Satoh, Toshifumi Satoh, Seiichi Taguchi
    JOURNAL OF BIOSCIENCE AND BIOENGINEERING 122 6 660 - 665 2016年12月 [査読有り][通常論文]
     
    Thermostable enzymes are required for the rapid and sustainable production of polyhydroxyalkanoate (PHA) in vitro. The in vitro synthesis of PHA using the engineered thermostable synthase PhaC1(SG)(STQK) has been reported; however, the non-thermostable enzymes acetyl-CoA synthetase (ACS) and CoA transferase (CT) from mesophilic strains were used as monomer-supplying enzymes in this system. In the present study, acs and ct were cloned from the thermophilic bacteria Pelotomaculum thermopropionicum JCM10971 and Thermus thermophilus JCM10941 to construct an in vitro PHA synthesis system using only thermostable enzymes. ACS from P. thermopropionicum (ACS(Pt)) and CT from I thermophilus (CTTt) were confirmed to have high thermostability, and their optimal temperatures were around 60 degrees C and 75 degrees C, respectively. The in vitro PHA synthesis was successfully performed by ACS(Pt), CTTt, PhaC1(SG)(STQK), and poly(3-hydroxybutyrate) [P(3HB)] was synthesized at 45 degrees C. Furthermore, the yields of P(3HB) and P(lactate-co-3HB) at 37 degrees C were 1.4-fold higher than those of the in vitro synthesis system with non-thermostable ACS and CT from mesophilic strains. Overall, the thermostable ACS and CT were demonstrated to be useful for the efficient in vitro PHA synthesis at relatively high temperatures. (C) 2016, The Society for Biotechnology, Japan. All rights reserved.
  • Yanli Zhou, Chunhong Zhang, Yuan Qiu, Lijia Liu, Taotao Yang, Hongxing Dong, Toshifumi Satoh, Yoshio Okamoto
    MOLECULES 21 11 2016年11月 [査読有り][通常論文]
     
    A phenylacetylene containing the L-valine ethyl ester pendant (PAA-Val) was synthesized and polymerized by an organorhodium catalyst (Rh(nbd)BPh4) to produce the corresponding one-handed helical cis-poly(phenylacetylene) (PPAA-Val). PPAA-Val showed a unique temperature-triggered switchable helix-sense in chloroform, while it was not observed in highly polar solvents, such as N,N'-dimethylformamide (DMF). By heating the solution of PPAA-Val in chloroform, the sign of the CD absorption became reversed, but recovered after cooling the solution to room temperature. Even after six cycles of the heating-cooling treatment, the helix sense of the PPAA-Val's backbone was still switchable without loss of the CD intensity. The PPAA-Val was then coated on silica gel particles to produce novel chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). These novel PPAA-Val based CSPs showed a high chiral recognition ability for racemic mandelonitrile (alpha = 2.18) and racemic trans-N,N'-diphenylcyclohexane-1,2-dicarboxamide (alpha = 2.60). Additionally, the one-handed helical cis-polyene backbone of PPAA-Val was irreversibly destroyed to afford PPAA-Val-H by heating in dimethyl sulfoxide (DMSO) accompanied by the complete disappearance of the Cotton effect. Although PPAA-Val-H had the same L-valine ethyl ester pendants as its cis-isomer PPAA-Val, it showed no chiral recognition. It was concluded that the one-handed helical cis-polyene backbone of PPAA-Val plays an important role in the chiral recognition ability.
  • Guihua Cui, Zhengguo Gao, Nannan Qiu, Toshifumi Satoh, Toyoji Kakuchi, Qian Duan
    MATERIALS 9 11 2016年11月 [査読有り][通常論文]
     
    Regioselective modification of D-glucosamine (2-amino-2-deoxy-D-glucopyranose, GA) through C-1 and C-2 positions to synthesized thermo-responsive D-Glucosamine-poly(N-isopropylacrylamide) (PNIPAM) via atom transfer radical polymerization (ATRP) was investigated for the first time. Two different schemes of the synthesis for GA derivatives (GA-PNIPAM (i) and (ii)) with well-defined structures using 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-beta-D-glucopyranose and 1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-beta-D-glucopyranose intermediates were examined. The GA-PNIPAM (ii) had an amino at C-2 position, while there was a hydroxyl in GA-PNIPAM (i) at this position. Both the resulting oligomers (i) and (ii) had a narrow dispersity, and no significant cytotoxic response of copolymers (i) and (ii) was observed in the cell line over the concentration range from 0.1 mu g/mL to 1000 mu g/mL at any of the exposure times. In addition, it was discovered that GA-PNIPAM (i) and (ii) inhibited the proliferation of Human Hepatocellular Carcinoma Cells HepG2 as the concentration and the time changed, and the inhibitory activity of polymer (ii) was higher than that of he (i). The results suggest that the GA-PNIPAM polymers show excellent biocompatibility in vitro.
  • Na Xue, Xing-Ping Qiu, Yougen Chen, Toshifumi Satoh, Toyoji Kakuchi, Francoise M. Winnik
    JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS 54 20 2059 - 2068 2016年10月 [査読有り][通常論文]
     
    The heat-induced phase transition of aqueous solutions of Poly(N-isopropylacrylamide) (PNIPAM) in water is examined for a four-arm PNIPAM star (s-PNIPAM), a cyclic PNI-PAM (c-PNIPAM), and their linear counterparts (l-PNIPAM) in the case of polymers (1.0 g L-1) of 12,700 g mol(-1) < M-n < 14,700 g mol(-1). Investigations by turbidity, high-sensitivity differential scanning calorimetry (HS-DSC), and light scattering (LS) indicate that the polymer architecture has a strong effect on the cloud point (T-c: decrease for s-PNIPAM; increase for c-PNIPAM), the phase transition enthalpy change (Delta H decrease for s-PNIPAM and c-PNIPAM), and the hydrodynamic radius of the aggregates formed above T-c (R-H: c-PNIPAM< s-PNIPAM< l-PNIPAM). The properties of s-PNIPAM are compared with those of previously reported PNIPAM star polymers (3 to 52 arms). The overall observations are described in terms of the arm molecular weight and the local chain density in the vicinity of the core of the star, by analogy with the model developed for PNIPAM brushes on nanoparticlesor planar surfaces. (C) 2016 Wiley Periodicals, Inc.
  • WANG Jau‐Tzeng, SAITO Kengo, WU Hung‐Chin, SUN Han‐Sheng, HUNG Chih‐Chien, CHEN Yougen, ISONO Takuya, KAKUCHI Toyoji, SATOH Toshifumi, CHEN Wen‐Chang
    NPG Asia Materials (Web) 8 Aug WEB ONLY  2016年08月 [査読無し][通常論文]
  • Jau-Tzeng Wang, Kengo Saito, Hung-Chin Wu, Han-Sheng Sun, Chih-Chien Hung, Yougen Chen, Takuya Isono, Toyoji Kakuchi, Toshifumi Satoh, Wen-Chang Chen
    NPG ASIA MATERIALS 8 2016年08月 [査読有り][通常論文]
     
    Diblock copolymers consisting of electron-donating poly[2,7-(9,9-dihexylfluorene)] (PF) rods and electron-withdrawing poly (pendent isoindigo) (Piso) coils were designed and synthesized through a click reaction. The electronic properties and interchain organization of the copolymers could be tuned by varying the PF/Piso ratio (PF14-b-Piso(n) (n= 10, 20, 60 and 100)). The highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of the studied polymers were progressively reduced as the length of Piso increased, affecting the charge trapping and intramolecular charge transfer environment between PF and Piso domains. Thermally treated PF14-b-Piso(n) thin films exhibited a clear nanofibrillar structure, and the d-spacing was enhanced systematically as the Piso chain length increased. Resistive memory characteristics were explored with a sandwich indium tin oxide/PF14-b-Piso(n)s/Al device configuration. The enhanced conjugated PF conducting channels led to stable resistance switching behavior, exhibiting volatile SRAM (static random access memory) (PF14-b-Piso(10)) and nonvolatile WORM (write-once-read-many-times) (PF14-b-Piso(20), PF14-b-Piso(60), PF14-b-Piso(100)) characteristics with a large ON/OFF ratio (10(6)) and a stable retention time (10(4) s). A more appealing feature is that such memory cells were integrated on a soft poly(dimethylsiloxane) substrate, allowing for the development of a stretchable data storage device. Reliable and reproducible electrical characteristics, including SRAM- and WORM-type memories, could be explored as the device was stretched under an applied tensile strain ranging from 0 to 50%. The studied donor-acceptor copolymers indeed showed great potential for stretchable electronic applications with controllable digital information storage characteristics.
  • Takuya Isono, Kana Miyachi, Yusuke Satoh, Ryosuke Nakamura, Yao Zhang, Issei Otsuka, Kenji Tajima, Toyoji Kakuchi, Redouane Borsali, Toshifumi Satoh
    MACROMOLECULES 49 11 4178 - 4194 2016年06月 [査読有り][通常論文]
     
    This paper describes the systematic investigation into the aqueous self-assembly of a series of block copolymers (BCPs) consisting of maltoheptaose (MH; as the A block) and poly(e-caprolactone) (PCL; as the B block), i.e., linear AB-type diblock copolymers with varied PCL molecular weights (MH-b-PC1-(2.5(k,3.3k,5k10k))), AB(y)-type = 2, MH-b(PCL5k) 2; y = 3, MH-b-(PCL3.3k)(3)), A(2)B(2)-type ((MH)(2)-b(PCL(5)k)(2)), and AxB-type miktoarm star polymers (x = 2, (MH)2-b-PCL10k; x = 3, (MH)(3)-b-PCLiok), which had been precisely synthesized via the combination of the living ring opening polymerization and click reaction. Under similar conditions, the nanoprecipitation method was employed to self -assemble them in an aqueous medium. Imaging and dynamic light scattering techniques indicated the successful formation of the carbohydrate -decorated nanoparticles via self -assembly. The MH-b-PCLs formed regular core shell micellar nanoparticles with the hydrodynamic "radius (Rh) of 17-43 nm. MH-b-(PCL5k)2 and MH-b-(PCL3.3k)(3), which have an NPCL comparable to MH-b-PCLiok, were found to form large compound micelles with relatively large radii (Rh of 49 and 56 nm, respectively). On the other hand, (MH),-b-(PCL5k),, (MH),-b-PCLiok, and (MH)3-bPCLiok predominantly formed the regular core shell micellar nanoparticles (Rh = 29-39 nm) with a size smaller than that of MH-b-PCLiok (Rh = 43 nm).
  • Kenji Tajima, Kosuke Iwamoto, Yasuharu Satoh, Ryosuke Sakai, Toshifumi Satoh, Tohru Dairi
    APPLIED MICROBIOLOGY AND BIOTECHNOLOGY 100 10 4375 - 4383 2016年05月 [査読有り][通常論文]
     
    Polyhydroxyalkanoates (PHAs) incorporating vinyl-bearing 3-hydroxyalkanoates were prepared in 8.5-12.9 g L-1 yield. The molar ratios (0-16 mol%) of the vinyl-bearing 3-hydroxyalkanoate derivatives were controlled by the continuous feeding of undecylenate at various concentrations. Subsequently, the PHAs were functionalized by UV-initiated thiol-ene click reaction and chemical modification. H-1 NMR spectra suggested that 3-mercaptopropionic acid and 2-aminoethanethiol were successfully introduced into the vinyl-bearing PHA. Subsequently, chemical modification using fluorescein or a fibronectin active fragment (GRGDS) was attempted. The former yielded a PHA derivative capable of emitting fluorescence under UV irradiation, which was useful for determining the miscibility of PHA in a composite film comprising poly-EY-lactic acid (PLLA) and PHA. In the latter case, PHA bearing GRGDS peptides exhibited cell adhesiveness, suggesting that its biocompatibility was improved upon peptide introduction. Taken together, the UV-initiated thiol-ene click reaction was demonstrated to be useful in PHA modification.
  • Jau-Tzeng Wang, Shoichi Takashima, Hung-Chin Wu, Yu-Cheng Chiu, Yougen Chen, Takuya Isono, Toyoji Kakuchi, Toshifumi Satoh, Wen-Chang Chen
    ADVANCED FUNCTIONAL MATERIALS 26 16 2695 - 2705 2016年04月 [査読有り][通常論文]
     
    Field-effect transistor memories usually require one additional charge storage layer between the gate contact and organic semiconductor channel. To avoid such complication, new donor-acceptor rod-coil diblock copolymers (P3HT(44)-b-Piso(n)) of poly(3-hexylthiophene)(P3HT)-block-poly(pendent isoindigo) (Piso) are designed, which exhibit high performance transistor memory characteristics without additional charge storage layer. The P3HT and Piso blocks are acted as the charge transporting and storage elements, respectively. The prepared P3HT(44)-b-Piso(n) can be self-assembled into fibrillar-like nanostructures after the thermal annealing process, confirmed by atomic force microscopy and grazing-incidence X-ray diffraction. The lowest-unoccupied molecular orbital levels of the studied polymers are significantly lowered as the block length of Piso increases, leading to a stronger electron affinity as well as charge storage capability. The field-effect transistors (FETs) fabricated from P3HT(44)-b-Piso(n) possess p-type mobilities up to 4.56 x 10(-2) cm(2) V-1 s(-1), similar to that of the regioregular P3HT. More interestingly, the FET memory devices fabricated from P3HT(44)-b-Piso(n) exhibit a memory window ranging from 26 to 79 V by manipulating the block length of Piso, and showed stable long-term data endurance. The results suggest that the FET characteristics and data storage capability can be effectively tuned simultaneously through donor/acceptor ratio and thin film morphology in the block copolymer system.
  • Seiya Kikuchi, Yougen Chen, Kodai Kitano, Shin-ichiro Sato, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 49 8 3049 - 3060 2016年04月 [査読有り][通常論文]
     
    The tris(pentafluorophenyl)borane- (B(C6F5)(3)-) catalyzed group transfer polymerization (GTP) of N,N-disubstituted acrylamide (DAAm) using a moisture-tolerant hydrosilane (HSi) as part of the initiator has been intensively investigated in this study. The screening experiment using various HSis suggested that dimethylethylsilane (Me2EtSiH) with, the least steric bulkiness was the most appropriate reagent for the polymerization control. The chemical structure of the DAAms significantly affected the livingness of the polymerization. For instance, the polymerization of N,N-diethylacrylamide (DEtAAm) using Me2EtSiH only showed better control over the molecular weight distribution, while that of N-acryloylmorpholine (MorAAm) with a more obstructive side group using the same HSi afforded precise control of the molecular weight as well as its distribution. Given that the entire polymerization was composed of the monomer activation, the in situ formation of a silyl ketene aminal as the true initiator by the 1,4-hydrosilylation of DAAm, and the GTP process, the polymerization mechanism was discussed in detail for each specific case, e.g., the B(C6F5)(3)-catalyzed polymerizations of DEtAAm and MorAAm and the polymerization of MorAAm using B(C6F5)(3) and Me3SiNTf2 as a double catalytic system. Finally, the convenient alpha-end-functionalization of poly(N,N-disubstituted acrylamide) (PDAAm) was achieved by the in situ preparation of functional silyl ketene aminals through the 1,4-hydrosilylation of functional methacrylamides, which has no polymerization reactivity in the Lewis acid-catalyzed GTP, followed by the Me3SiNTf2-catalyzed GTP of DAAms.
  • Tsuyoshi TOTANI, Takuya KUNI, Toshifumi SATOH, Takuya ISONO, Masashi WAKITA, Harunori NAGATA
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 14 ists30 Pi_1 - Pi_6 2016年 [査読有り][通常論文]
  • 磯野拓也, 佐藤敏文
    CSJ Current Review 22 204‐205  2016年 [査読無し][通常論文]
  • Han-Sheng Sun, Yougen Chen, Wen-Ya Lee, Yu-Cheng Chiu, Takuya Isono, Toshifumi Satoh, Toyoji Kakuchi, Wen-Chang Chen
    POLYMER CHEMISTRY 7 6 1249 - 1263 2016年 [査読有り][通常論文]
     
    We report the synthesis, morphology, and field effect transistor memory application of malto-heptaose-based block copolymers, maltoheptaose-block-poly(1-pyrenylmethyl methacrylate) (MH-bPPyMA), and their supramolecules with (4-pyridyl)-acceptor-(4-pyridyl), MH(4Py-Acceptor-4Py)(x)-b-PPyMA. MH-b-PPyMA was prepared by the combination of the t-Bu-P-4-catalyzed group transfer polymerization and the Cu(I)-catalyzed azide-alkyne cycloaddition reaction. After the thermal annealing process, the MH-b-PPyMA bulk sample underwent microphase separation to form the sub-10 nm periodic self-assembled nanostructure. The self-assembled morphologies transform from the hexagonal cylinder packing to the body-centered cubic sphere arrangement and the disordered spherical nano-domain with the increase of the PPyMA segment length. On the contrary, only the spherical nanodomain was observed in the thermo-annealed thin film samples of both MH-b-PPyMA and MH(4Py-Acceptor-4Py)(x)-b-PPyMA. The electrical characteristics of the p-type pentacene-based OFET memory device were studied using the thermo-annealed polymer thin film as the electret layer. The MH(4Py-Acceptor-4Py)(x)-b-PPyMA-based organic field effect transistor (OFET) devices had the high hole mobility of 0.20-1.08 cm(2) V-1 s(-1) and the ON/OFF current (I-ON/I-OFF) ratio of 10(7)-10(8), in which the acceptor of the benzo[c][1,2,5] thiadiazole (BT) based device possessed the higher hole mobility than that of the isoindigo-based one due to the more ordered packing pentacene crystals. The memory window (Delta V-TH) of the supramolecule-based device was increased with enhancing the 4Py-Acceptor-4Py blending composition, and that of the MH(4Py-BT-4Py)(1.5)-b-PPyMA10-based device had the largest Delta V-TH of ca. 9 V, a long-term retention time greater than 10(4) s and the high I-ON/I-OFF memory ratio of 10(6)-10(7) (reading at V-g = 0 V) for more than 100 programming/erasing cycles. Our results demonstrate that the bio-related block copolymers and their supramolecular thin film could be used as electret layers for high-performance nonvolatile flash green memory devices.
  • Yusuke Satoh, Kana Miyachi, Hirohiko Matsuno, Takuya Isono, Kenji Tajima, Toyoji Kakuchi, Toshifumi Satoh
    MACROMOLECULES 49 2 499 - 509 2016年01月 [査読有り][通常論文]
     
    A comprehensive set of amphiphilic star-shaped block copolyethers with a fixed molecular weight and composition was synthesized via the t-Bu-P-4-catalyzed ring opening polymerization (ROP) of 2-(2-(2-methoxyethoxy)-ethoxy)ethyl glycidyl ether as a hydrophilic monomer and decyl glycidyl ether as a hydrophobic monomer. The three and four-armed star-block copolyethers, i.e., the (AB)(3)-, (BA)(3)-, (AB)(4)-, and (BA)(4)-type star-block copolyethers, where A and B represent hydrophilic and hydrophobic blocks, respectively, were synthesized by the sequential t-Bu-P-4-catalyzed block copolymerization using tri- and tetra-alcohol initiators, respectively, according to the core-first method. The homogeneous growth of each arm was confirmed by cleaving the linkages between the initiator residue and polyether arms. The synthesis of the A(2)B(2)-, AB(2)-, and A(2)B-type miktoarm star copolyethers was achieved by the combination of the t-Bu-P-4-catalyzed ROP and azido-alkyne click chemistry. The azido- and ethynyl-functionalized precursor polyethers with the predicted molecular weights were separately prepared by the t-Bu-P-4-catalyzed ROP with the aid of functional initiators as well as a terminator. The intermolecular click reaction of the precursors provided the desired miktoarm star copolyethers. All the obtained star-shaped block copolyethers had a comparable monomer composition (degree of polymerization = 50:50) and total molecular weight (ca. 22 200 g mol(-1)) with a narrow dispersity (<1.05). The hydrodynamic diameter and the cloud point analyses for the aqueous micellar solution of the amphiphilic star-shaped block copolyethers revealed that the self-assembly properties were affected by the block arrangements and branched architectures of the amphiphilic polymers.
  • Kodai Watanabe, Ryoto Tanaka, Kenji Takada, Myung-Jin Kim, Jae-Suk Lee, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    POLYMER CHEMISTRY 7 29 4782 - 4792 2016年 [査読有り][通常論文]
     
    A comprehensive examination of the synthesis of single-chain nanoparticles (SCNPs) from statistical copolymers of n-butyl methacrylate (BMA) and 3-butenyl methacrylate (3BMA), i.e., P(BMA-co-3BMA)s, via the intramolecular olefin metathesis reaction under high dilution conditions is described. The olefin metathesis reaction of P(BMA-co-3BMA) using Grubbs' 2nd generation catalyst in CH2Cl2 efficiently gave the corresponding SCNPs under mild conditions. We achieved the size-controlled synthesis of the SCNPs by adjusting the following factors: (1) the olefin content in the precursor, (2) the molecular weight of the precursor, and (3) the solvent quality of the reaction medium. The hydrodynamic radius and the intrinsic viscosity of the resultant SCNPs were investigated by DLS and viscometric measurements, respectively, which provided further evidence of SCNP formation with controlled diameters. Furthermore, the above-established intramolecular olefin metathesis approach was successfully applied to poly(acrylate), poly(styrene), and poly(ester) precursors, which proved that the present approach could be applied to a wide range of olefin-containing precursors to give SCNPs with various functional groups.
  • Hikaru Yanai, Osamu Kobayashi, Kenji Takada, Takuya Isono, Toshifumi Satoh, Takashi Matsumoto
    CHEMICAL COMMUNICATIONS 52 16 3280 - 3283 2016年 [査読有り][通常論文]
     
    In the presence of a strong carbon acid, the sequential Mukaiyama-Michael reaction using two different Michael acceptors proceeded and the reaction of ketene silyl acetal derived from EtOAc with alpha-pyrones as primal acceptors yielded the corresponding cyclic ketene silyl acetals, which were reactive enough to undergo the following reaction with second acceptors.
  • Takuya Isono, Issei Otsuka, Sami Halila, Redouane Borsali, Toyoji Kakuchi, Toshifumi Satoh
    Journal of Photopolymer Science and Technology 28 6 755 - 762 2015年11月16日 [査読無し][通常論文]
     
    The present review summarizes our recent results regarding the synthesis and morphological characterization of sugar-based hybrid block copolymers (BCPs) consisting of maltoheptaose (MH) and poly(ε-caprolactone) (PCL). The AB-, AB2-, AB3-, ABA-, and A2B-type BCPs, in which the A and B blocks are MH and PCL, respectively, were synthesized by combining the living polymerization and click reaction. The in-situ small angle X-ray scattering experiments revealed the formation of ordered microphase-separated structures with a sub-20 nm periodicity.
  • Yougen Chen, Keita Fuchise, Toshifumi Satoh, Toyoji Kakuchi
    Anionic Polymerization: Principles, Practice, Strength, Consequences and Applications 451 - 494 2015年09月01日 [査読有り][通常論文]
     
    Group transfer polymerization (GTP) as one of the living polymerizations was put forward over 30 years ago by DuPont for the upscale and cost-reducing synthesis of acrylic polymers. In the GTP process, a silyl ketene acetal compound is used as an initiator and a Lewis base/acid as the catalysts, and polymerizations can be operated at advantageously moderate temperatures when compared with the conventional living anionic polymerizations of acrylic monomers. GTP using conventional catalysts, referred to as conventional GTP, had experienced a booming development during 1980-1990s. In retrospect, most of the studies in this field before 2007 had been focusing on the optimization of conventional catalysts, the exploration of applicable monomers, and the molecular design of polymeric architectures. In addition, debates on polymerization mechanisms involving associative and dissociative routes had also been discussed. In contrast to the conventional GTP, the recent progress (2007~) in this field has been mainly reflected on the significant and creative utilization of organocatalysts, such as strong organic Lewis acids/bases, which might be termed as organocatalytic GTP. This subchapter strives to provide a latest, systematic, and comprehensive summary throughout the over 30-year development, and in particular, the organocatalytic GTP will be emphatically described.
  • Chunhong Zhang, Rui Ma, Hailun Wang, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi, Lijia Liu, Yoshio Okamoto
    CHIRALITY 27 8 500 - 506 2015年08月 [査読有り][通常論文]
     
    Four poly(phenylacetylene)s (PPA-1, PPA-2, PPA-3, PPA-4) bearing phenylcarbamate residues of L-phenylglycinol and amide linkage as pendants were prepared to be used as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC), and the influences of coating solvents, dimethylformamide (DMF) and tetrahydrofuran (THF), which were used for coating the polymers on silica gel, on the helical structure of the polymers and their chiral recognition abilities were investigated. The structure analysis of PPA-1, PPA-2, PPA-3, PPA-4 by H-1 nuclear magnetic resonance (NMR), size exclusion chromatography (SEC), optical rotation, and circular dichroism (CD) spectra indicated that the polymers possess the cis-transoidal structure with dynamic helical conformation. The polymers in THF seem to have shorter conjugated helical main chains along with a tighter twist conformation than those in DMF. The chiral recognition abilities of PPA-1, PPA-2, PPA-3, PPA-4 with the different helical structures induced by the coating solvents were evaluated as the CSPs in HPLC. The helical structures of PPA-1, PPA-2, PPA-3, PPA-4 induced with THF are preferable for chiral recognition for some racemates compared to those induced with DMF, and higher chiral recognition abilities of PPA-1, PPA-2, PPA-3, PPA-4 were achieved using THF. Chirality 27:500-506, 2015. (c) 2015 Wiley Periodicals, Inc.
  • Rarm Phinjaroenphan, Young Yong Kim, Brian J. Ree, Takuya Isono, Jinseok Lee, Supagorn Rugmai, Heesoo Kim, Santi Maensiri, Toyoji Kakuchi, Toshifumi Satoh, Moonhor Ree
    MACROMOLECULES 48 16 5816 - 5833 2015年08月 [査読有り][通常論文]
     
    Two series of crystalline-crystalline miktoarm star polymers were prepared and their thin film morphologies were investigated in detail by synchrotron grazing incidence X-ray scattering (GIXS): poly(n-hexyl isocyanate)(5000) poly(epsilon-caprolactone) (1-3)(17000) (PHIC(5k)-PCL1-3(17k)) and poly(n-hexyl isocyanate) (10000) poly(epsilon-caprolactone)(1-3)(10000) (PHIC(10k)-PCL1-3(10k)). In addition, their thermal properties were examined. All miktoarm star polymers revealed a two-step thermal degradation behavior where the PHIC arm was degraded first, followed by the PCL arm underwent degradation. Interestingly, all miktoarms were found to show a highly enhanced thermal stability, regardless of their molecular weight over 3k to 17k, which might be attributed to their one-end group capped with the counterpart arm(s) via arm-joint formation. Surprisingly, all miktoarm star polymers always developed only lamellar structure in toluene- and chloroform-annealed films via phase-separation, regardless of the length of PHIC arm as well as the length and number of PCL arm. Despite having highly imbalanced volume fractions, lamellar structure was constructed in the films of miktoarm star polymers through the override of volume fraction rule based on the rigid chain properties, self-assembling characteristics, conformational asymmetry, and compressibilities of PHIC and PCL arms. Furthermore, the orientation of such lamellar structures was controlled by the selection of either toluene or chloroform in the solvent-annealing process. The PHIC arm phases in the lamellar structures favorably formed a mixture of edge-on and face-on structures with fully extended backbone and bristle conformations even under the confined lamellar geometry and arm-joint. The PCL arm phases still crystallized, forming fringed-micelle like structures in which orthorhombic crystals were laterally grown along the in-plane direction of lamellae although their crystallization was somewhat suppressed by the confined lamellar geometry and arm-joint. Overall, crystalline-crystalline PHIC-PCL1-3 miktoarm polymers demonstrated very interesting but unusual, very complex hierarchical structures in the solvent-annealed thin films.
  • Han-Sheng Sun, Yu-Cheng Chiu, Wen-Ya Lee, Yougen Chen, Akira Hirao, Toshifumi Satoh, Toyoji Kakuchi, Wen-Chang Chen
    MACROMOLECULES 48 12 3907 - 3917 2015年06月 [査読有り][通常論文]
     
    We report the synthesis and electric device applications of oligosaccharide-based diblock copolymers consisting of a maltoheptaose (MH) block and a poly(4-oligofluorenylstyrene) block (PStFl(n), n = 1 or 2), referred to as MH-b-PStFl(n). MH-b-PStFl(n) was prepared by the Cu(I)-catalyzed click reaction of azido-terminated PStFl(n) (PStFl(n)-N-3), which was obtained from the azidation reaction of the bromo-terminated PStFl(n) (PStFl(n)-Br), with excess ethynylterminated MH in the THF/DMF mixture solvent. The resulting diblock copolymers self-assembled to spherical microdomains with sub-10 nm sizes in both bulk and thin film state after annealing process. Thereafter, the MH-b-PStFl(n) thin film (similar to 50 nm) with the self-assembled nanoscale spherical aggregates was used as the charge storage layer for the pentacene-based field-effect transistor type memory devices. The MH-b-PStFl(n)-based devices had the excellent hole mobility (0.25-0.52 cm(2) V-1 s(-1)) and the high ON/OFF current (I-ON/I-OFF) ratio of 10(7)-10(8), of which the MH-b-PStFl(1)-based one had the higher mobility than that of the MH-b-PStFl(2)-based one because the pentacene crystal in the former device possessed the larger grain size and fewer boundaries. On the other hand, the MH-b-PStFl(2)-based device showed a larger memory window than the MH-b-PStFl(1)-based one because the stronger electron-donating effect of the difluorenyl group in MH-b-PStFl(2) increased the charge storage capability of its related device. All the memory devices showed a long-term retention time over 10(4) s with the high I-ON/I-OFF ratio of 10(6)-10(8). Among these devices, the MH-b-PStFl(1)-based device showed a good WRER endurance over 180 cycles. This work not only demonstrates the tunable electrical memory characteristics by adjusting the pi-conjugation length of the oligofluorenyl side chain in the polymer electret but also provides a promising approach for developing the next-generation "green electronics" using natural materials.
  • Yuichi Hirai, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Tomohiro Seki, Hajime Ito, Hiroyuki Fueno, Kazuyoshi Tanaka, Toshifumi Satoh, Yasuchika Hasegawa
    INORGANIC CHEMISTRY 54 9 4364 - 4370 2015年05月 [査読有り][通常論文]
     
    Syntheses of novel luminescent Eu(III) coordination glasses 1 ([Eu(hfa)(3)(o-dpeb)](2)), 2 ([Eu(hfa)(3)(m-dpeb)](3)), and 3 ([Eu(hfa)(3)(p-dpeb)](n)) are reported. They are composed of Eu(III) ions, hexafluoroacetylacetonato (hfa) ligands, and unique bent-angled phosphine oxide (o-, m-, p-dpeb) ligands with ethynyl groups. Their coordination structures and glass formability are dependent on the regiochemistry of substitution in regard to the internal benzene core. Single-crystal X-ray analyses and DFT calculation reveals dinuclear, trinuclear, and polymer structures for Eu(III) coordination glasses 1, 2, and 3, respectively. Those compounds show characteristic glass-transition (T-g = 25-96 degrees C) and strong luminescence properties (phi(Ln) = 72-94%).
  • Takuya Isono, Shunsuke Asai, Yusuke Satoh, Toshimitsu Takaoka, Kenji Tajima, Toyoji Kakuchi, Toshifumi Satoh
    MACROMOLECULES 48 10 3217 - 3229 2015年05月 [査読有り][通常論文]
     
    The combination of t-Bu-P-4 and alcohol was found to be an excellent catalytic system for the controlled/living ring-opening polymerization (ROP) of N,N-disubstituted glycidylamine derivatives, such as N,N-dibenzylglycidylamine (DBGA), N-benzyl-N-methylglycidylamine, N-glycidylmorpholine, and N,N-bis(2-methoxyethyl)glycidylamine, to give well-defined polyethers having various pendant tertiary amino groups with predictable molecular weights and narrow molecular weight distributions (typically M-w/M-n, < 1.2). The tBu-P-4-catalyzed ROP of these monomers in toluene at room temperature proceeded in a living manner, which was confirmed by a MALDI-TOF MS analysis, kinetic measurement, and postpolymerization experiment. The well-controlled nature of the present system enabled the production of the block copolymers composed of the glycidylamine monomers. The polyethers having pendant primary and secondary amino groups, i.e., poly(glycidylamine) and poly(glycidylmethylamine), respectively, were readily obtained by the debenzylation of poly(DBGA) and poly(BMGA), respectively, through the treatment with Pd/C in THF/MeOH under a hydrogen atmosphere. To the best of our knowledge, this report is the first example of the controlled/living polymerization of glycidylamine derivatives, providing a rapid and comprehensive access to the polyethers having primary, secondary, and tertiary amino groups.
  • Kosuke Makiguchi, Chihiro Asakura, Kazuma Yanai, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULAR SYMPOSIA 349 1 74 - 84 2015年03月 [査読無し][通常論文]
     
    The ring-opening polymerization (ROP) of 1,5-dioxepan-2-one (DXO) catalyzed by diphenyl phosphate (DPP) using 3-phenyl-1-propanol (PPA) as an initiator has been studied. The polymerization in toluene at room temperature produced poly(1,5-dioxepan-2-one) (PDXO) with a narrow polydispersity index. For the initial [DXO](0)/[PPA](0)/[DPP](0) of 50/1/1, the molecular weight determined from H-1 NMR (M-n,M-NMR) of 5670gmol(-1) agreed with the calculated one (M-n,M-calcd) of 5680gmol(-1). The obtained PDXO possessing a PPA residue at the -chain end was confirmed by the H-1 NMR and MALDI-TOF MS measurements. The livingness of the ROP of DXO was supported by the kinetic and chain-extension experiments. The diblock and random copolymerizations of DXO and E-caprolactone (CL) afforded respective copolymers. The monomer reactivity ratios were obtained as r(DXO)=0.59 and r(CL)=1.19 using the Kelen-Tudos method, and the random copolymers showed different thermal properties corresponding to copolymer compositions.
  • Issei Otsuka, Yao Zhang, Takuya Isono, Cyrille Rochas, Toyoji Kakuchi, Toshifumi Satoh, Redouane Borsali
    MACROMOLECULES 48 5 1509 - 1517 2015年03月 [査読有り][通常論文]
     
    The present paper describes the sub-10 nm scale self-assembly of AB-type diblock, ABA-type triblock, and A(2)B-type miktoarm star copolymers consisting of maltoheptaose (MH: A block) and polystyrene (PS: B block). These block copolymers (BCPs) were synthesized through coupling of end-functionalized MH and PS moieties. Small-angle X-ray scattering and atomic force microscope investigations indicated self-organized cylindrical and lamellar structures in the BCP bulks and thin films with domain spacing (d) ranging from 7.65 to 10.6 nm depending on the volume fraction of MH block (phi(MH)), Flory-Huggins interaction parameter (chi), and degree of polymerization (N). The BCP architecture also governed the morphology of the BCPs, e.g. the AB-type diblock copolymer (phi(MH) = 0.42), the ABA-type triblock copolymer (phi(MH) = 0.40), and the A2B-type miktoarm star copolymer (phi(MH) = 0.45) self-organized into cylinder (d = 7.65 nm), lamellar (d = 8.41 nm), and lamellar (d = 9.21 nm) structures, respectively.
  • Chunhong Zhang, Hailun Wang, Taotao Yang, Rui Ma, Lijia Liu, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi, Yoshio Okamoto
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 53 6 809 - 821 2015年03月 [査読有り][通常論文]
     
    A series of novel stereoregular one-handed helical poly(phenylacetylene) derivatives (PPA-1 and PPA-1a similar to g) bearing L-phenylglycinol and its phenylcarbamate residues as pendants was synthesized for use as chiral stationary phases (CSPs) for HPLC, and their chiral recognition abilities were evaluated using 13 racemates. The phenylcarbamate residues include an unsubstituted phenyl, three chloro-substituted phenyls (3-Cl, 4-Cl, 3,5-Cl-2), and three methyl-substituted phenyls (3-CH3, 4-CH3, 3,5-(CH3)(2)). The acidity of the phenylcarbamate N-H proton and the hydrogen bonds formed between the N-H groups of the phenylcarbamate residues were dependent on the type, position, and the number of substituents on the phenylcarbamate residues. The chiral recognition abilities of these polymers significantly depended on the dynamic helical conformation of the main chain with more or less regularly arranged pendants. The chiral recognition abilities seem to be improved by the introduction of substituents on the phenylcarbamate residues, and PPA-1d bearing the more acidic N-H groups due to the 3,5-dichloro substituents, exhibited a higher chiral recognition than the others. PPA-1d showed an efficient chiral recognition for some racemates, and baseline separation was possible for racemates 5, 11, 12, and 15. (C) 2014 Wiley Periodicals, Inc.
  • Kenji Takada, Takahiro Ito, Kodai Kitano, Shinji Tsuchida, Yu Takagi, Yougen Chen, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 48 3 511 - 519 2015年02月 [査読有り][通常論文]
     
    The group transfer polymerization (GTP) with N-(trimethylsilyl)bis(trifluoromethanesulfonyl)imide (Me3SiNTf2) and 1-methoxy-1-triisopropylsiloxy-2-methyl-1-propene (iPr-SKA) has been studied using methyl acrylate (MA), ethyl acrylate (EA), n-butyl acrylate (nBA), 2-ethylhexyl acrylate (EHA), cyclohexyl acrylate (cHA), dicyclopentanyl acrylate (dcPA), tert-butyl acrylate (tBA), 2-methoxyethyl acrylate (MEA), 2-(2-ethoxyethoxy)ethyl acrylate (EEA), 2-(dimethylamino)ethyl acrylate (DMAEA), allyl acrylate (AlA), propargyl acrylate (PgA), 2-(triisopropylsiloxy)ethyl acrylate (TIPS-HEA), and triisopropylsilyl acrylate (TIPSA). Except for tBA and DMAEA, the GTPs of all other monomers described above proceeded rapidly in a living manner and produced well-defined homo acrylate polymers. The living nature of the GTPs of such acrylate monomers was further applied to the postpolymerizations of MA, EA, nBA, and MEA and also to the sequential GTPs of diverse acrylate monomers for preparing di- and multiblock acrylate polymers. In greater detail, the AB and BA diblock copolymers, (ABC)(4) dodecablock terpolymer, (ABCD)(3) dodecablock quaterpolymer, and ABCDEF hexablock sestopolymer were synthesized by sequential GTP methods using various acrylate monomers.
  • 磯野拓也, 佐藤悠介, 覚知豊次, 佐藤敏文
    高分子論文集 72 5 295 - 305 2015年 [査読有り][通常論文]
     
    This comprehensive paper describes the anionic ring-opening polymerization of substituted epoxides using a phosphazene base catalyst, t-Bu-P-4, and its application for the synthesis of architecturally complex polyethers. The t-Bu-P-4-catalyzed ROP of 1,2-butylene oxide (BO) produced the poly(BO) having the predicted molecular weight and narrow polydispersity. The kinetic analysis revealed that the ROP system proceeded in a living manner. The t-Bu-P(4)catalyzed ROP was then applied to the polymerization of various epoxides having a variety of side chains, e.g. styrene oxide. The synthesis of star-shaped polyethers was achieved by the t-Bu-P-4-catalyzed ROP using polyols as an initiator. The syntheses of cyclic-, figure-eight-shaped, and tadpole-shaped polyethers were also achieved via the intramolecular click reaction of the well-defined linear precursors bearing azido and ethynyl functions at designed positions.
  • Ofosu-Twum Eric, Yougen Chen, Kenji Takada, Shin-ichiro Sato, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER CHEMISTRY 6 45 7841 - 7850 2015年 [査読有り][通常論文]
     
    The synthesis of miktoarm star-shaped polymers has been studied using various poly(methyl methacrylate)s (PMMAs) functionalized with a hydroxyl group, which were prepared by organocatalyzed group transfer polymerization (GTP) of methyl methacrylate, followed by Mukaiyama aldol-type termination of a silyl ketene acetal (SKA) moiety at the living PMMA end. To further elucidate this method, the effects of the employed catalysts, polymer chain length, and benzaldehyde derivatives on the omega-end-functionalization efficiency (%F) were investigated in detail. The electrophilic termination of the living PMMA end with benzaldehyde as the terminator produced a structurally defect-free omega-end-functionalized PMMA with a hydroxyl group (PMMA-OH). In addition, a two-arm PMMA with two hydroxyl groups (PMMA(2)-OH2) and a three-arm star-shaped PMMA with three hydroxyl groups (PMMA(3)-OH3), whose hydroxyl groups were located at the polymer chain centers, were prepared using terephthalaldehyde and benzene-1,3,5-tricarbaldehyde, respectively. The PMMA-OH, PMMA(2)-OH2, and PMMA(3)-OH3 obtained were then used as macroinitiators for the ring-opening polymerization (ROP) of D-lactide (DLA) to synthesize an AB block copolymer, and A(2)B(2) and A(3)B(3) type miktoarm copolymers.
  • Takuya Isono, Issei Otsuka, Sami Halila, Redouane Borsali, Toyoji Kakuchi, Toshifumi Satoh
    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY 28 5 635 - 642 2015年 [査読有り][通常論文]
     
    The present review summarizes our recent results regarding the synthesis and morphological characterization of sugar-based hybrid block copolymers (BCPs) consisting of maltoheptaose (MH) and poly(epsilon-caprolactone) (PCL). The AB-, AB(2)-, AB(3)-, ABA-, and A(2)B-type BCPs, in which the A and B blocks are MH and PCL, respectively, were synthesized by combining the living polymerization and click reaction. The in-situ small angle X-ray scattering experiments revealed the formation of ordered microphase-separated structures with a sub-20 nm periodicity.
  • Yougen Chen, Kenji Takada, Naoya Kubota, Ofosu-Twum Eric, Takahiro Ito, Takuya Isono, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER CHEMISTRY 6 10 1830 - 1837 2015年 [査読有り][通常論文]
     
    The present study describes the alpha- and omega-end-functionalization of poly(methyl methacrylate)s (PMMAs) by organocatalyzed group transfer polymerization (GTP) using both functional silyl ketene acetal (SKA) initiators and alpha-phenylacrylate terminators. The syntheses of structurally defect-free alpha-end-functionalized PMMAs with hydroxyl, ethynyl, vinyl, and norbornenyl groups (HO-PMMA, HC C-PMMA, H2C CH-PMMA, and NB-PMMA, respectively) were achieved by either the N-(trimethylsilyl)bis(trifluoromethanesulfonyl)imide-( Me3SiNTf2-) or t-Bu-P-4-catalyzed GTP of MMA using functional trimethyl SKAs (1a-1d). On the other hand, the omega-end-functionalized PMMAs with ethynyl, hydroxyl, vinyl, and bromo groups (PMMA-C CH, PMMA-OH, PMMA-CH CH2, and PMMA-Br, respectively) were for the first time obtained by the Me3SiNTf2-catalyzed GTP of MMA followed by a termination reaction using functional alpha-phenylacrylates (2a-2d). All the polymerizations produced end-functionalized PMMAs with controlled molar masses, narrow dispersities, and defect-free polymer structures as designed. The quantitative incorporation of functionalities into the alpha- or omega-end of the PMMAs was confirmed by the H-1 NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) measurements.
  • Jau-Tzeng Wang, Yu-Cheng Chiu, Han-Sheng Sun, Kohei Yoshida, Yougen Chen, Toshifumi Satoh, Toyoji Kakuchi, Wen-Chang Chen
    POLYMER CHEMISTRY 6 12 2327 - 2336 2015年 [査読有り][通常論文]
     
    We report the synthesis and characterization of multifunctional triblock copolymers, poly(1-pyrenemethylmethacrylate)-block-poly(N-isopropylacrylamide)-block-poly(N-methylolacrylamide) (PPyb-PNIPAAm-b-PNMA), and their electrospun (ES) nanofibers for temperature or metal-ion sensing. The triblock copolymers are composed of fluorescent and metal-ion-sensitive PPy, thermoresponsive PNIPAAm, and chemically crosslinkable PNMA segments. Non-crosslinked ES nanofibers are initially prepared using the aforementioned PPy-b-PNIPAAm-b-PNMA triblock copolymers followed by thermal crosslinking. It is found that ES nanofibers prepared from PPy-b-PNIPAAm-b-PNMA can self-assemble to form nano-scale spherical aggregates with PNMA located at the core, PNIPAAm at the center layer, and PPy at the shell. This self-assembly characteristic therefore induces a strong excimer emission between the pyrenyl moieties. The crosslinking process between PNMA blocks is then implemented to stabilize the ES nanofibers since the non-crosslinked ones are metastable objects. The resulting crosslinked nanofibers exhibit a predominant wettability and dimension stability under aqueous states, and can perform a detectable photoluminescence transition at different temperatures or toward an Fe3+ ion. In contrast to their counterpart drop-cast film, ES nanofibers with a high surface/volume ratio have obviously higher sensing ability toward thermal stimuli and metal ions, and are expected to be applied as multifunctional sensory devices.
  • Yougen Chen, Kodai Kitano, Shinji Tsuchida, Seiya Kikuchi, Kenji Takada, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER CHEMISTRY 6 18 3502 - 3511 2015年 [査読有り][通常論文]
     
    The group transfer polymerization (GTP) of alkyl methacrylates has been studied using hydrosilane and tris(pentafluorophenyl) borane (B(C6F5)(3)) as the new initiation system. For the B(C6F5)(3)-catalyzed polymerization of methyl methacrylate (MMA) using triethylsilane, tri-n-butylsilane (nBu(3)SiH), dimethylphenylsilane (Me2PhSiH), triphenylsilane, and triisopropylsilane, nBu(3)SiH and Me2PhSiH were suitable for producing well-defined polymers with predicted molar masses and a low polydispersity. The livingness of the GTP of MMA using Me2PhSiH/B(C6F5)(3) was verified by the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) measurement of the resulting polymers, kinetic analyses, and chain extension experiments. The B(C6F5)(3)-catalyzed GTP using Me2PhSiH was also applicable for other alkyl methacrylates, such as the n-propyl, n-hexyl, n-decyl, 2-ethylhexyl, iso-butyl, and cyclohexyl methacrylates. The in situ formation of the silyl ketene acetal by the 1,4-hydrosilylation of MMA was proved by the MALDI-TOF MS and H-2 NMR measurements of the polymers obtained from the B(C6F5)(3)-catalyzed GTPs of MMA with Me2PhSiH or Me2PhSiD, which was terminated using CH3OH or CD3OD.
  • Yougen Chen, Nao Xiao, Moe Fukuoka, Kohei Yoshida, Qian Duan, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER CHEMISTRY 6 19 3608 - 3616 2015年 [査読有り][通常論文]
     
    The present study describes the precise synthesis and thermoresponsive properties of two types of four-arm star-shaped poly(N-isopropylacrylamide)s (PNIPAM), i.e., the covalently linked one (3) and the non-covalently Ru(II)-chelated one (5). The atom transfer radical polymerization (ATRP) method was used to prepare the azido-terminated PNIPAM (1) arm using (2-azidoethyl)-2-chloropropionamide (AECP) as the initiator. 3 was subsequently prepared based on the click reaction of 1 with a multifunctional linker of tetra[(5-hexynyloyloxy)methyl]methane. For comparison, its linear counterpart 2 was also synthesized as a reference polymer by the same method using ethyl 5-hexynyloate. The four-arm star-shaped PNIPAM Ru complex 5, on the other hand, was prepared by a click-to-chelate approach, which involves the click reaction of 1 with 2,6-diethynylpyridine to produce the macroligand of 2,6-bis(1-PNIPAM-1,2,3-triazol-4-yl) pyridine (4) and the chelating reaction of RuCl3 with 4 to afford 5. The thermoresponsive properties of the resulting polymers were investigated using a UV-vis spectrophotometer by measuring the optical transmittance of the polymer solution with varying solution temperature and the cloud point (T-c) at 50% transmittance intensity in order to assess their thermoresponsive properties. The detailed thermoresponsive properties of these polymers, including the effects of the polymer terminal and core linkage and constituents of the four-arm star-shaped PNIPAMs on the T-c, are significantly described in the later part of this study.
  • Tatsuya Saito, Yusuke Aizawa, Kenji Tajima, Takuya Isono, Toshifumi Satoh
    POLYMER CHEMISTRY 6 24 4374 - 4384 2015年 [査読有り][通常論文]
     
    The ring-opening polymerizations (ROPs) of epsilon-caprolactone (epsilon-CL), delta-valerolactone, 1,5-dioxepan-2-one, trimethylene carbonate, and L-lactide were performed in the bulk using an organophosphate, such as diphenyl phosphate, bis(4-nitrophenyl)phosphate, and di(2,6-xylyl)phosphate, as the catalyst. The ROPs proceeded in a well-controlled manner even under the bulk conditions to afford well-defined aliphatic polyesters, polyester-ether, and polycarbonate with relatively low dispersities. Notably, the amount of the loaded catalyst was successfully reduced when compared to the conventional organophosphate-catalyzed ROP in solution. A kinetic study revealed the controlled/living nature of the present bulk ROP system, which allowed us to produce the block copolymers composed of polyesters, polyester-ether, and polycarbonate in one pot. Syntheses of the end-functionalized poly(epsilon-caprolactone)s (PCLs) and poly(trimethylene carbonate) were successfully demonstrated using alcohol initiators possessing highly reactive functional groups. Furthermore, the alpha,beta-dihydroxy telechelic PCL-diol as well as the three-and fourarmed star-shaped PCL-polyols were also easily obtained by using the polyols as an initiator. Finally, the one-pot synthesis of polyurethane via the ROP of epsilon-CL and a subsequent urethane forming reaction was demonstrated by taking advantage of the dual catalytic abilities of the organophosphate for both the ROP and polyurethane synthesis.
  • Seiya Kikuchi, Yougen Chen, Kodai Kitano, Kenji Takada, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER CHEMISTRY 6 38 6845 - 6856 2015年 [査読有り][通常論文]
     
    The group transfer polymerization (GTP) of N,N-diethylacrylamide (DEAA) was studied using various combinations of an organic acid of N-(trimethylsilyl) bis-(trifluoromethanesulfonyl) imide (Me3SiNTf2), 1-(2,3,4,5,6-pentafluorophenyl)-1,1-bis(trifluoromethanesulfonyl) methane (C6F5CHTf2), and tris(pentafluorophenyl) borane (B(C6F5)(3)) and a silyl ketene acetal (SKA) of 1-methoxy-1-(trimethylsiloxy)-2-methyl-1-propene (MeSKA), 1-methoxy-1-(triethylsiloxy)-2-methyl-1-propene (EtSKA), 1-methoxy1-(triisopropylsiloxy)-2-methyl-1-propene (iPrSKA), and 1-methoxy-1-(triphenylsiloxy)-2-methyl-1-propene (PhSKA), among which the combination of B(C6F5)(3) and EtSKA afforded a relatively better control over the molecular weight distribution. The polymerization behavior of DEAA using B(C6F5)(3) and EtSKA was then intensively investigated in terms of the polymerization kinetics, chain extension experiments, and MALDI-TOF MS analyses, by which the polymerization was proven to proceed in a living fashion though an induction period of tens of minutes occurred. The B(C6F5)(3)-catalyzed GTP was further extended to various N, N-disubstituted acrylamides (DAAs), such as N, N-dimethylacrylamide (DMAA), N, N-di-n-propylacrylamide (DnPAA), N-acryloylpiperidine (API), N-acryloylmorpholine (NAM), N-(2-methoxyethyl)-N-methylacrylamide (MMEAA), N, N-bis(2-methoxyethyl) acrylamide (BMEAA), N, N-diallylacrylamide (DAlAA), and N-methyl-N-propargylacrylamide (MPAA). Finally, the livingness of the polymerization was used to synthesize acrylamide-acrylamide block copolymers and methacrylate-acrylamide hetero-block copolymers.
  • Kengo Saito, Takuya Isono, Han-Sheng Sun, Toyoji Kakuchi, Wen-Chang Chen, Toshifumi Satoh
    POLYMER CHEMISTRY 6 39 6959 - 6972 2015年 [査読有り][通常論文]
     
    A series of rod-coil miktoarm star copolymers consisting of poly[2,7-(9,9-dihexylfluorene)] (PF) and polylactide (PLA) arms as the rod and coil segments, respectively, were synthesized by combining the chain-growth Suzuki-Miyaura coupling polymerization and living ring-opening polymerization (ROP). First, PFs having a hydroxyl group at the alpha-chain end (PF-BnOH) were prepared by the polymerization of 2-(7-bromo-9,9-dihexyl-9H-fluorene-2-yl) 4,4,5,5-tetramethyl-1,2,3-dioxaborolane using the initiating system of 4-(tetrahydropyran-2'-yloxymethyl)-iodobenzene/Pd-2(dba)(3)/t-Bu3P. After a couple of chain end modifications, PFs having one, two, and three hydroxyl groups at the alpha-chain end (PF-OH, PF-(OH)(2), and PF-(OH)(3), respectively) were obtained with dispersity (D) values of less than 1.29. The obtained PF-OH, PF-(OH)(2), and PF-(OH)(3) were used as the initiators for the organic base-catalyzed ROP of rac-lactide to produce the AB type linear diblock (PF-b-PLA) and AB(2) and AB(3) type miktoarm star copolymers (PF-b-(PLA)(2) and PF-b-(PLA)(3), respectively). The self-assembled nanostructures in the thermally-annealed PF-b-(PLA)(x)s (x = 1, 2, and 3) were evaluated in the bulk by synchrotron small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The PF-b-PLA, PF-b-(PLA)(2), and PF-b-(PLA)(3) with the PF weight fractions of 0.52-0.56 were found to form poorly ordered PLA cylindrical structures in the PF matrix due to a strong rod-rod interaction of the PF segment. On the other hand, these BCPs with the PF weight fractions of 0.22-0.23 exhibited the hexagonally close-packed cylinder (Hex) morphologies, in which the cylindrical PF phase was embedded in the PLA matrix. More interestingly, the domain-spacing (d) values for the Hex morphologies decreased with the increasing PLA arm number despite each BCP having a comparable molecular weight and PF weight fraction: d = 26.4 nm for PF-b-PLA, d = 21.7 nm for PF-b-(PLA)(2), and d = 18.6 nm for PF-b-(PLA)(3).
  • 國拓也, 戸谷剛, 佐藤敏文, 磯野拓也, 脇田督司, 永田晴紀
    熱物性 29 4 173 - 178 日本熱物性学会 2015年 [査読無し][通常論文]
     
    本研究では超小型人工衛星用蓄熱材料として,結晶転移によって蓄熱を行うトランス-1, 4-ポリブタジエン(TPBD)に注目した.同一のサンプルに対して蓄熱量の測定および分子構造の測定を行った.測定結果から,TPBDの分子構造内の-CH<sub>2</sub>の自動酸化によるC-H結合の変化が,蓄熱量に影響を与えていることが確認できた.連続使用の中での蓄熱量の変化を確認するために熱サイクル試験を行った.熱サイクル試験によって得られた温度履歴から蓄熱量及び放熱量の算出を行った結果,蓄熱量は60 J/gから90 J/gの間に,放熱量は-65 J/gから-100 J/gの間になることが分った.静止軌道衛星約4年半の運用期間に相当する1700回の蓄熱および放熱では蓄熱量の熱サイクル劣化は確認できなかった.
  • Rarm Phinjaroenphan, Young Yong Kim, Sungmin Jung, Takuya Isono, Yusuke Satoh, Santi Maensiri, Supagorn Rugmai, Toyoji Kakuchi, Toshifumi Satoh, Moonhor Ree
    SCIENCE OF ADVANCED MATERIALS 6 11 2526 - 2531 2014年11月 [査読有り][通常論文]
     
    The nanoscale thin film morphologies of a series of interesting miktoarm star polymers composed of a highly rigid and crystallizable poly(n-hexyl isocyanate) (PHIC) arm and one to three flexible and crystallizable poly(epsilon-caprolactone) (PCL) arms were investigated using synchrotron grazing incidence X-ray scattering methods. Nanoscale thin films of a PHIC and a PCL homopolymer were also characterized for comparison. The PCL homopolymer and star polymers formed horizontally oriented lamellar structures in toluene-annealed films. The horizontal lamellar structures formed in the miktoarm star polymer films were quite different from those observed in common flexible block copolymer specimens. Interestingly, the structural parameters associated with the star polymer films were significantly influenced by the exceptional rigidity of the PHIC arm chain and by the number and length of the PCL arms. This study demonstrated that a miktoarm star polymer system consisting of rigid and crystallizable arms could form thin films with a morphology that is suitable for specific target applications.
  • Young Yong Kim, Sungmin Jung, Changsub Kim, Brian J. Ree, Daisuke Kawato, Naoki Nishikawa, Daichi Suemasa, Takuya Isono, Toyoji Kakuchi, Toshifumi Satoh, Moonhor Ree
    MACROMOLECULES 47 21 7510 - 7524 2014年11月 [査読有り][通常論文]
     
    A series of miktoarm star polymers, [poly(n-hexyl isocyanate)(12K)][poly(epsilon-caprolactone)(13)(5K)] (PHICPCL13) (composed of a rigid self-assembling PHIC arm and one to three flexible crystallizable PCL arms), were investigated to examine the polymers thermal properties and nanoscale thin film morphologies. The miktoarm polymers were stable up to 180 degrees C. The PHIC and PCL arm components underwent phase separation during the solution casting, drying, and post toluene-annealing processes, forming interesting but very complex thin film morphologies. The resulting thin film morphologies were examined in detail for the first time using synchrotron grazing incidence X-ray scattering (GIXS) measurements and quantitative data analysis. All of the miktoarm star polymer films formed vertically well-oriented lamellar structures, regardless of the number and length of PCL arms. These structures were quite different from the cylindrical structures commonly observed in conventional flexible diblock copolymer films having comparable volume fractions. The individual PHIC and PCL lamellar domains self-assembled to form their own respective morphological structures. The PHIC lamellae consisted of a mixture of horizontal and vertical multibilayer structure domains, as observed in the PHIC homopolymer film. The PCL lamellae formed fringed micelle-like crystals and/or highly imperfect folded crystals that differed significantly from the structures found in a PCL homopolymer film composed of typical folded lamellar crystals. These PCL crystals were formed with a mixture of vertical and horizontal orthorhombic lattices. Overall, the GIXS analysis revealed that the parameters that characterized the hierarchical structures in the thin films depended significantly on the number and length of the PCL arm and its crystallization characteristics as well as the chain rigidity and multibilayer structure formation characteristics of the PHIC arm.
  • Takuya Isono, Yohei Kondo, Shun Ozawa, Yougen Chen, Ryosuke Sakai, Shin-ichiro Sato, Kenji Tajima, Toyoji Kakuchi, Toshifumi Satoh
    MACROMOLECULES 47 20 7118 - 7128 2014年10月 [査読有り][通常論文]
     
    Random and block copolymerizations of poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) macromonomers having an exo-norbornene group at the alpha- or pi-chain end (D/L ratio = 1/1, M-n = ca. 5000 g mol(-1)) were performed via ring-opening metathesis polymerization to produce the brush random and block copolymers consisting of parallel or antiparallel aligned PLLA and PDLA side chains on a poly(norbornene) backbone. The molecular weight and polydispersity index of the brush copolymers were in the range of 40 300-458 000 g mol(-1) and 1.031.14, respectively. Despite such high molecular weights, these brush copolymers formed a stereocomplex without homochiral crystallization. The melting temperature (T-m) and crystallinity (X) of the resulting stereocomplex varied depending on the backbone length, relative chain direction, and distribution of the PLLA/PDLA side chains. The parallel brush copolymers showed significantly higher T-m and X values than the antiparallel ones.
  • Keita Fuchise, Shinji Tsuchida, Kenji Takada, Yougen Chen, Toshifumi Satoh, Toyoji Kakuchi
    ACS MACRO LETTERS 3 10 1015 - 1019 2014年10月 [査読有り][通常論文]
     
    The group transfer polymerization (GTP) of n-butyl acrylate (nBA) using hydrosilane (R3SiH) and tris-(pentafluoropheny)borane (B(C6F5)(3)) has been studied, which did not need to use the initiator of a silyl ketene acetal (SICA) as the starting polymerization component. B(C6F5)(3) catalyzed the in situ 1,4-hydrosilylation of nBA by R3SiH to generate the corresponding SKA prior to the polymerization of nBA, which was confirmed by the H-1 NMR measurement of the model reaction. The formed SKA performed as the initiator for the B(C6F5)(3)-catalyzed GTP of nBA leading to well-defined polymers with targeted molar masses and low dispersities.
  • Yougen Chen, Nao Xiao, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER CHEMISTRY 5 17 4993 - 5001 2014年09月 [査読有り][通常論文]
     
    This study describes the first convenient preparation of 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 11-, and 12-armed star-shaped poly(styrene oxide) (PSO) Ru(II) complexes using a click-to-chelate approach. This approach involves the combination of the click reaction and stepwise chelating reactions of Ru(II)(DMSO)(4)Cl-2 with macroligands, 2-(1-PSOn-1,2,3-triazol-4-yl)pyridine (PSOn-tapy) or 2-(1-PSOm-1,2,3-triazol-4-yl)-6-(1-PSOn-1,2,3-triazol-4-yl)pyridine (PSOm-bitapy-PSOn) (m, n = 1, 2, or 3). Click chemistry was used to prepare the PSOn-tapy and PSOm-bitapy-PSOn macroligands. More specifically, PSOn-tapy was prepared by reacting the azido-functionalized PSOn (PSOn-N-3) with excess 2-ethynylpridine. On the other hand, PSOm-bitapy-PSOn was obtained by the click reaction of excess PSOn-N-3 with 2,6-diethynylpridine to afford (PSOn)(2)-bitapy when m equals n, and by the stepwise click reactions of PSOm-N-3 and PSOn-N-3 with 2,6-diethynylpridine to produce PSOm-bitapy-PSOn when m is not equal to n. In order to obtain these polymer-substituted macroligands, PSOn-N-3 was initially synthesized by the living ring-opening polymerization (ROP) of styrene oxide (SO) using t-Bu-P-4 as a catalyst and the azido-functionalized mono- or multi-hydroxyl compounds, e.g., 6-azido-1-hexanol, 2-((6-azidohexyloxy)methyl)-2-methylpropane-1,3-diol (1) and 2-((6-azidohexyloxy)methyl)-2-(hydroxymethyl)propane-1,3-diol (2) as initiators.
  • Nannan Qiu, Yanhui Li, Shuangli Han, Toshifumi Satoh, Toyoji Kakuchi, Qian Duan
    JOURNAL OF APPLIED POLYMER SCIENCE 131 15 40523,1-8  2014年08月 [査読有り][通常論文]
     
    A series of well-defined linear poly(N-isopropyl acrylamide) with an asymmetrical zinc(II) porphyrin (ZnPor-PAM) end group was synthesized by atom transfer radical polymerization, wherein 5,10,15,20-tetra(p-bromopropanoyloxyethylphenyl) zinc porphyrin tripropionate was used as the initiator and CuBr/tris(2-dimeoethyl)amine was used as the catalyst system. The structure of the ZnPor-PAM was characterized by Fourier transform infrared spectroscopy and H-1-NMR. In addition, the polydispersity index (PDI) obtained by gel permeation chromatography indicated that the molecular weight distribution was narrow; thus, the polymerization was well controlled (1.05<PDI<1.21). Because of the incorporation of hydrophobic porphyrin, the lower critical solution temperature of ZnPor-PAM was lower than that of the N-isopropyl acrylamide homopolymer. Most interestingly, the ZnPor-PAM possessed remarkable photocatalytic activity for the oxidative degradation of methylene blue in the presence of hydrogen peroxide under visible-light radiation. Moreover, ZnPor-PAM could be reused through the uncomplicated procedure, which exploited the thermoresponsive properties of ZnPor-PAM without any significant loss in activity. (c) 2014 Wiley Periodicals, Inc.
  • Yu-Cheng Chiu, Tzu-Ying Chen, Yougen Chen, Toshifumi Satoh, Toyoji Kakuchi, Wen-Chang Chen
    ACS APPLIED MATERIALS & INTERFACES 6 15 12780 - 12788 2014年08月 [査読無し][通常論文]
     
    Organic nonvolatile transistor memory devices of the n-type semiconductor N,N'-bis(2-phenylethyl)-perylene-3,4:9,10-tetracarboxylic diimide (BPE-PTCDI) were prepared using various electrets (i.e., three-armed star-shaped poly[4-(diphenylamino)benzyl methacrylate] (N(PTPMA)(3)) and its blends with 6,6-phenyl-C-61-butyric acid methyl ester (PCBM), 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pen) or ferrocene). In the device using the PCBM:N(PTPMA)3 blend electret, it changed its memory feature from a write-once-read-many (WORM) type to a flash type as the PCBM content increased and could be operated repeatedly based on a tunneling process. The large shifts on the reversible transfer curves and the hysteresis after implementing a gate bias indicated the considerable charge storage in the electret layer. On the other hand, the memory characteristics showed a flash type and a WORM characteristic, respectively, using the donor/donor electrets TIPS-pen:N(PTPMA)(3) and ferrocene:N(PTPMA)(3). The variation on the memory characteristics was attributed to the difference of energy barrier at the interface when different types of electret materials were employed. All the studied memory devices exhibited a long retention over 10(4) s with a highly stable read-out current. In addition, the afore-discussed memory devices by inserting another electret layer of poly(methacrylic acid) (PMAA) between the BPE-PTCDI layer and the semiconducting blend layer enhanced the write-read-erase-read (WRER) operation cycle as high as 200 times. This study suggested that the energy level and charge transfer in the blend electret had a significant effect on tuning the characteristics of nonvolatile transistor memory devices.
  • Seiya Kikuchi, Yougen Chen, Keita Fuchise, Kenji Takada, Junsuke Kitakado, Shin-ichiro Sato, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER CHEMISTRY 5 16 4701 - 4709 2014年08月 [査読有り][通常論文]
     
    The t-Bu-P-4-catalyzed group transfer polymerization (GTP) of 2-(dimethylamino)ethyl methacrylate (DMAEMA) using multi-functional GTP initiators that bear multiple silyl ketene acetal moieties (MTS3, MTS4, MTS6, and MTS12) homogeneously proceeded and rapidly completed to afford well-defined starshaped poly[2-(dimethylamino)ethyl methacrylate]s (s-PDMAEMAs) with relatively narrow polydispersities. The molecular weights (MWs) of s-PDMAEMAs were well-controlled by optimizing the molar ratios of the monomer to initiators. For the structural analyses, the arm number and length uniformity of each s-PDMAEMA were then investigated by arm cleavage experiments using a transesterification method. The thermoresponsive properties in an aqueous solution of the resulting s-PDMAEMAs together with their analogous linear PDMAEMAs (l-PDMAEMAs), in terms of polymer concentration, molecular weight, and arm number, were eventually elucidated based on turbidimetry curves.
  • Kenji Takada, Keita Fuchise, Naoya Kubota, Takahiro Ito, Yougen Chen, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 47 16 5514 - 5525 2014年08月 [査読有り][通常論文]
     
    The alpha-functionalized (hydroxyl, ethynyl, vinyl, and norbornenyl), omega-functionalized (ethynyl, vinyl, hydroxyl, and bromo), and alpha,omega-functionalized polyacrylates were precisely synthesized by the N-(trimethylsily)bis-(trifluoroethanesulfonyl)imide (Me3SiNTf2)-catalyzed group transfer polymerization (GTP) of n-butyl acrylate (nBA). The alpha-functionalization and omega-functionalization were carried out using the functional triisopropylsilyl ketene acetal as the initiator (initiation approach) and 2-phenyl acrylate derivatives as the terminator (termination approach) for the organocatalytic GTP, respectively. All the polymerizations precisely occurred and produced well-defined end-functionalized poly(n-butyl acrylate)s which had predictable molecular weights and narrow molecular weight distributions. High-molecular-weight polyacrylates were easily synthesized using both approaches. In addition, the alpha,omega-functionalized (hetero)telechelic polyacrylates were synthesized by the combination of the initiation and termination approaches. The structure of the obtained polyacrylates and degree of functionalization were confirmed by the H-1 NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS) measurements. The spectra of the H-1 NMR and MALDI-TOF MS showed that the end-functionalization quantitatively proceeded without any side reactions.
  • Kosuke Makiguchi, Tatsuya Saito, Toshifumi Satoh, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 52 14 2032 - 2039 2014年07月 [査読有り][通常論文]
     
    The ring-opening polymerization (ROP) of -butyrolactone (-BL) has been studied using the organocatalysts of diphenyl phosphate (DPP) and bis(4-nitrophenyl) phosphate (BNPP). The controlled ROP of -BL was achieved using BNPP, whereas that of using DPP was insufficient because of its low acidity. For the BNPP-catalyzed ROP of -BL, the dual activation property for -BL and the chain-end models of poly(-butyrolactone) (PBL) were confirmed by NMR measurements. The optimized polymerization condition for the ROP of -BL proceeded through an O-acyl cleavage to produce the well-defined PBLs with molecular weights up to 10,650 g mol-1 and relatively narrow polydispersities of 1.19-1.39. Functional initiators were utilized for producing the end-functionalized PBLs with the ethynyl, maleimide, pentafluorophenyl, methacryloyl, and styryl groups. Additionally, the diblock copolymers consisting of the PBL segment with the polyester or polycarbonate segments were prepared by the BNPP-catalyzed ROPs of epsilon-caprolactone or trimethylene carbonate without quenching. (c) 2014 Wiley Periodicals, Inc.
  • Nannan Qiu, Yanhui Li, Shuangli Han, Guihua Cui, Toshifumi Satoh, Toyoji Kakuchi, Qian Duan
    JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY 283 38 - 44 2014年06月 [査読有り][通常論文]
     
    A series of well-defined star-shaped poly(N-isopropylacrylamide) (ZnTHPP-PAM) with zinc-porphyrin as the core was synthesized by atom transfer radical polymerization (ATRP). Zinc(11)meso-tetra(p-bromopropionylphenyl)porphyrin (ZnTHPP-Br) was employed as the initiator, and CuBr/tris(2-dimeoeth-yl)amine(Me6TREN) was selected as the catalyst system. The structures of the target polymers were characterized by FT-IR and H-1 NMR. The polydispersity index (PDI) was obtained by gel permeation chromatography (GPC), indicating that the molecular weight distribution was narrow and the polymerization was well controlled. The lower critical solution temperatures (LCST) for the aqueous solutions of ZnTHPP-PAM were generated by using turbidimetry method. The result exhibited lower value as compared to that of NIPAM homopolymer, which was arose from the incorporation of the hydrophobic porphyrin core. The photocatalytic activity of ZnTHPP-PAM was verified by the degradation of Methylene Blue in the presence of hydrogen peroxide under visible light. It was worth noting that the catalytic efficiency was higher at the LCST of the polymer, which benefited to the reuse of the photocatalyst. (C) 2014 Elsevier B.V. All rights reserved.
  • Yang Yang, Yanhui Li, Nannan Qiu, Guihua Cui, Toshifumi Satoh, Qian Duan
    CHEMISTRY-AN ASIAN JOURNAL 9 5 1379 - 1387 2014年05月 [査読有り][通常論文]
     
    The novel aminoporphyrin-end-functionalized poly(N-isopropylacrylamide) (PNIPAM) polymer H2N-TPP-PNIPAM (TPP=5,10,15,20-tetraphenyl-21H,23H-porphyrin) behaves as a multifunctional platform that displays a photodynamic effect, thermosensitivity, and fluorescence properties. The polymer was designed by using an asymmetrical aminoporphyrin (i.e., H2N-TPP-Cl) as the initiator for the atom-transfer radical polymerization of N-isopropylacrylamide (NIPAM). The polydispersity index (PDI) obtained by gel-permeation chromatography indicated that the molecular-weight distribution was narrow (1.09 < PDI < 1.27). The lower critical solution temperatures of H2N-TPP-PNIPAM showed a decreasing trend as the molecular weight was increased as a result of the incorporation of the porphyrin group at the end of the chain. The fluorescence spectra revealed the luminescent properties of the materials. The results of confocal laser scanning microscopy showed that the polymer could enter the cytoplasm through endocytosis. In addition, the multifunctional platform exhibited low toxicity against normal cells (L929) and cancer cells (Hela) and enhanced photodynamic activity towards HeLa cells, without significant necrocytosis towards L929 cells; as a result this material may be useful in the future for practical photodynamic therapy.
  • Priyank N. Shah, Chang-Geun Chae, Joonkeun Min, Ryotaro Shimada, Toshifumi Satoh, Toyoji Kakuchi, Jae-Suk Lee
    MACROMOLECULES 47 9 2796 - 2802 2014年05月 [査読有り][通常論文]
     
    A model chiral graft copolymer, poly(phenylacetylene)-g-poly(n-hexyl isocyanate) (PPA-g-PHIC), in which a chiral moiety is located at the end of each PHIC side chain, was synthesized. First, chiral PHIC macromonomers with a phenylacetylene end group were synthesized via living anionic polymerization using the functional initiator sodium N-(4-ethynylphenyl)benzamide (Na-4EPBA) and then end-capped using the chiral terminator (S)-2-acetoxypropionyl chloride ((S)-Ct). The molecular weights (MWs) of the PHIC macromonomers were controlled based on the feed ratio of the monomer to the initiator. Subsequent polymerization of PHIC macromonomers using Rh+(2,5-norbornadiene)[(eta(6)-C6H5)-B-(C6H5)(3)] (Rh(nbd)BPh4) catalyst generated chiral PPA-g-PHIC graft copolymers with varying graft strand lengths. Chiral macromonomers and graft copolymers were characterized by SEC-MALLS, NMR, and CD spectroscopy. This model chiral graft copolymer provided an excellent example of the transmission of stereochemical information from the side chain to the main chain, as a preferred helicity was induced in the PPA backbone of the graft copolymer even when chiral moieties were separated from the main chain by nanometer scale distances (5.4-13 nm). Furthermore, CD spectroscopy clearly showed that the CD intensity of the PPA main chain was directly dependent on the CD intensity of the optically active PHIC side chain determined by the strand length.
  • Takuya Isono, Yusuke Satoh, Kana Miyachi, Yougen Chen, Shin-ichiro Sato, Kenji Tajima, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 47 9 2853 - 2863 2014年05月 [査読有り][通常論文]
     
    This paper describes the synthesis of systematic sets of figure-eight- and tadpole-shaped amphiphilic block copolyethers (BCPs) consisting of poly(decyl glycidyl ether) and poly[2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether], together with the corresponding cyclic counterparts, via combination of the t-Bu-P-4-catalyzed ring-opening polymerization (ROP) and click cyclization. The clickable linear BCP precursors, with precisely controlled azido and ethynyl group placements as well as a fixed molecular weight and monomer composition (degree of polymerization for each block was adjusted to be around 50), were prepared by the t-Bu-P-4-catalyzed ROP with the aid of functional initiators and terminators. The click cyclization of the precursors under highly diluted conditions produced a series of cyclic, figure-eight-, and tadpole-shaped BCPs with narrow molecular weight distributions of less than 1.06. Preliminary studies of the BCPs self-assembly in water revealed the significant variation in their cloud points depending on the BCP architecture, though there were small architectural effects on their critical micelle concentration and morphology of the aggregates.
  • Kosuke Makiguchi, Seiya Kikuchi, Kazuma Yanai, Yoshitaka Ogasawara, Shin-ichiro Sato, Toshifumi Satoh, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 52 7 1047 - 1054 2014年04月 [査読有り][通常論文]
     
    The ring-opening polymerizations (ROPs) of epsilon-caprolactone (epsilon-CL) and L-lactide (LLA) have been studied using the organocatalysts of diphenyl phosphate (DPP) and 4-dimethylaminopyridine (DMAP). The dual activation property of DPP and the bifunctional activation property of DPP/DMAP were confirmed by the NMR measurement for epsilon-CL and its chain-end model of poly(epsilon-caprolactone) and for LLA and its chain-end model of poly(L-lactide) (PLLA), respectively. The molar ratio of DPP/DMAP was optimized as 1/2 for the ROP of LLA leading to the well-defined PLLA, such as the molecular weight determined from H-1 NMR measurement of 19,200 g mol(-1) and the narrow polydispersity of 1.10. Additionally, functional initiators were utilized for producing the end-functionalized PLLAs. The DPP-catalyzed ROPs of epsilon-CL and its analogue cyclic monomers and then the DPP/DMAP-catalyzed ROP of LLA produced block copolymers. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1047-1054
  • Naoya Sakai, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 47 5 1699 - 1704 2014年03月 [査読有り][通常論文]
     
    The self-assembling property of an amphiphilic rod rod diblock copolymer has been demonstrated using poly(n-hexyl isocyanate)-block-poly(2,5,8,11-tetraoxatridecyl isocyanate) (PHIC-b-PEOIC) with different degrees of polymerization for the PHIC and PEOIC segments. The critical aggregation concentrations (CAC) of PHIC-b-PEOIC decreased with the increasing fraction of the hydrophobic PHIC segment. The relation between the hydrodynamic radius (R-h) and the PHIC/PEOIC ratio differed from that for the radius of gyration (R-g). The self-assembled PHIC-b-PEOIC was stable in various polymer concentrations. The rho parameter (R-g/R-h) strongly suggested that the macromolecular architecture was a cylindrical micelle for PHIC13-b-PEOIC41 (rho = 1.63) and a spherical vesicle for PHIC22-b-PEOIC36 (rho = 1.09) and PHIC31-b-PEOIC31 (rho = 1.09). Transmission electron microscope (TEM) images closely agreed with the structures of the cylindrical micelle and spherical vesicle, which were expected based on the rho parameter.
  • Naoya Sakai, Mingoo Jin, Shin-ichiro Sato, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER CHEMISTRY 5 3 1057 - 1062 2014年02月 [査読無し][通常論文]
     
    Isocyanates with oligo(ethylene glycol) units have been designed and synthesized as 2,5-dioxaheptyl, 2,5,8-trioxadecyl, 3,6,9-trioxaundecyl, and 2,5,8,11-tetraoxatridecyl isocyanates (MeEO2IC, MeEO3IC, EtEO3IC, and MeEO4IC, respectively). The bulk polymerization of the isocyanates using n-butoxy(eta(5)-cyclopentadienyl)dichlorotitanium(IV) at 10 degrees C proceeded via a living manner to produce well-defined water-soluble polyisocyanates of PMeEO3IC, PEtEO3IC, and PMeEO4IC except for PMeEO2IC. The phase transition property of the obtained polyisocyanates was estimated by their cloud point temperatures (T(cp)s) in an aqueous solution (40 g L-1). For PMeEO3IC, the T-cp decreased from 90.0 to 74.9 degrees C with the increasing molecular weight (M-n,M-NMR) from 1960 to 9000 g mol(-1). The T-cp of 94.0 degrees C for PMeEO4IC (4460 g mol(-1)) was higher than that of 79.6 degrees C for PMeEO3IC (4560 g mol(-1)), and the T-cp decreased from 79.6 to 34.7 degrees C by changing from the methyl to the ethyl group in the oligo(ethylene glycol) units from PMeEO3IC to PEtEO3IC (4470 g mol(-1)).
  • 佐藤敏文
    高分子 63 1 23 - 24 2014年 [査読無し][通常論文]
  • TOTANI Tsuyoshi, SATOH Toshifumi, WAKITA Masashi, NAGATA Harunori
    Trans Jpn Soc Aeronaut Space Sci Aerosp Technol Jpn (Web) 12 ists29 PO.4.1-PO.4.5 (J-STAGE)  2014年 [査読有り][通常論文]
  • Toshifumi Satoh, Naoki Nishikawa, Daisuke Kawato, Daichi Suemasa, Sungmin Jung, Young Yong Kim, Moonhor Ree, Toyoji Kakuchi
    POLYMER CHEMISTRY 5 2 588 - 599 2014年 [査読有り][通常論文]
     
    Well-defined hydroxyl end-functionalized poly(n-hexyl isocyanate), PHIC-(OH)(2) and PHIC-(OH)(3), as rod-type macroinitiators were synthesized by the Cu-catalyzed azide-alkyne cycloaddition reactions of azido end-functionalized PHIC with ethynyl alcohol derivatives. The PHIC-(OH)(2) and PHIC-(OH) 3 were suitable macroinitiators for the ring-opening polymerization of L-LA and epsilon-CL leading to the synthesis of novel rod-coil type miktoarm star copolymers, PHIC-b-PLLA(2), PHIC-b-PLLA(3), PHIC-b-PCL2, and PHIC-b-PCL3, with controlled molecular weights, narrow polydispersities, and controlled arm numbers. Additionally, the thermal and solution properties of the obtained miktoarm star copolymers along with the corresponding block copolymers, PHIC-b-PLLA and PHIC-b-PCL, were characterized by TGA, DSC, and DLS analyses.
  • Kosuke Makiguchi, Takuto Yamanaka, Toyoji Kakuchi, Masahiro Terada, Toshifumi Satoh
    CHEMICAL COMMUNICATIONS 50 22 2883 - 2885 2014年 [査読有り][通常論文]
     
    A high enantiomer-selectivity for the polymerization of rac-lactide was achieved using chiral binaphthol-derived monophosphoric acids as organocatalysts. During the polymerization, D-lactide (DLA) preferentially polymerized via kinetic resolution with the maximum selectivity factor (k(D)/k(L)) of 28.3. The selective polymerization of DLA was derived from a dual activation, i.e., monomer activation and chain-end activation.
  • 佐藤敏文
    化学と工業 67 6 483 - 485 日本化学会 2014年 [査読無し][通常論文]
  • Takuya Isono, Issei Otsuka, Daichi Suemasa, Cyrille Rochas, Toshifumi Satoh, Redouane Borsali, Toyoji Kakuchi
    MACROMOLECULES 46 22 8932 - 8940 2013年11月 [査読有り][通常論文]
     
    Three different self-assembled nanostructures, i.e., lamellar (Lam), hexagonally close-packed cylinder (Hex), and body-centered cubic (BCC), have been obtained from ABA triblock (MH-b-PCL-b-MH) and A(2)B star-branched copolymers ((MH)(2)-b-PCL) consisting of maltoheptaose (MH, as the A block) and polycaprolactone (PCL, as the B block). MH-b-PCL-b-MH and(MH)(2)-b-PCL were synthesized by the click reaction of the alpha,omega-diazido and alpha,alpha-diazido end-functionalized PCLs with N-maltoheptaosyl-3-acetamido-1-propyne in high yields. The self-assembled nanostructures of the block copolymers (BCPs) in bulk were investigated as a function of temperature by time-resolved small-angle X-ray scattering using a synchrotron light source. The SAXS analysis revealed that the obtained BCPs exhibited microphase-separated structures with the domain-spacing of 10.4-21.0 nm. MH-b-PCL-b-MH (the MH volume fraction (phi(MH)) of 0.28 and 0.15) exhibited a hexagonally close-packed cylinder (Hex) at below ca. 230 degrees C, and the self-assembling behavior of MH-b-PCL-b-MH was essentially the same as that of the diblock counterpart, MH-b-PCL, having comparable phi(MH) values. The lamellar (Lam) morphology, which was unattainable from the corresponding linear counterparts, was observed from (MH)(2)-b-PCL (phi(MH) = 0.27 and 0.16). Furthermore, the microphase transitions from the Hex into the body-centered cubic sphere and the Lam into the Hex were observed upon the thermal caramelization of the MH block.
  • Chunhong Zhang, Hailun Wang, Qianqian Geng, Taotao Yang, Lijia Liu, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi, Yoshio Okamoto
    MACROMOLECULES 46 21 8406 - 8415 2013年11月 [査読有り][通常論文]
     
    Novel stereoregular helical poly(phenylacetylene) derivatives (PPA-Phe and PPA-Phg) with an amide linkage bearing L-phenylalanine and L-phenylglycine ethyl ester pendants were synthesized for use as chiral stationary phases (CSPs) in HPLC. The polymers showed different chiral recognition abilities depending on the coating solvents. Both PPA-Phe and PPA-Phg exhibited higher chiral recognitions when coated with CHCl3 by having preferable conformations. Their chiral recognition abilities depended on their molecular weight and optical rotations which were influenced by the polymerization solvents and monomer concentration. PPA-Phe and PPA-Phg showed rather different chiral recognitions, indicating that the benzyl group of the former and the phenyl group of the latter also play important roles in the chiral recognition. A few racemates were completely separated on PPA-Phe or PPA-Phg with separation factors comparable or higher than those obtained on the popular polysaccharide-based CSPs.
  • Takuya Isono, Yohei Kondo, Issei Otsuka, Yoshiharu Nishiyama, Redouane Borsali, Toyoji Kakuchi, Toshifumi Satoh
    MACROMOLECULES 46 21 8509 - 8518 2013年11月 [査読有り][通常論文]
     
    The synthesis of star-shaped polylactides (PLAs) having both poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) arms in one molecule, i.e., stereo-miktoarm star-shaped PLAs, is described. The azido-functionalized PDLAs and ethynyl-functionalized PLLA possessing linear and two- and three-branched structures were prepared by the ring-opening polymerization of D-lactide and L-lactide using azido- or ethynyl-functionalized initiators. The number-average molecular weights (M(n,NMR)s) of the PLAs were ca. 5000 g, mol(-1) with narrow molecular weight distributions (M-w/M(n)s) of less than 1.18. The click reaction of the azido-functionalized PDLAs and the ethynyl-functionalized PLLAs using the copper(I) bromide/N,N,N',N '',N ''-pentamethyldiethylenetriamine catalyst in a mixed solvent of dichloromethane/1,1,1,3,3,3-hexafluoro-2-propanol (14/1, v/v) gave a linear stereoblock PLA as well as 3-, 4-, 5-, and 6-armed stereo-miktoarm star-shaped PLAs with M(n,NMR)s of ca. 10 000 g mol(-1) and M-w/M(n)s of less than 1.16. The wide-angle X-ray scattering and differential scanning calorimetry measurements proved that these stereo-miktoarm star-shaped PLAs formed stereocomplex crystals without any trace of homochiral crystallization.
  • Guihua Cui, Shuiying Chen, Bao Jiang, Yan Zhang, Nannan Qiu, Toshifumi Satoh, Toyoji Kakuchi, Qian Duan
    OPTICAL MATERIALS 35 12 2250 - 2256 2013年10月 [査読有り][通常論文]
     
    The thermo-sensitive and fluorescent complexes containing Eu(III) or Tb(III) were synthesized and characterized, in which cholesterol-g-poly(N-isopropylacrylamide) (PNIPAM) copolymer was used as a polymer ligand. The results from the experiments indicated that Eu(III) or Tb(III) was bonded to nitrogen and oxygen atoms in the polymer chain. The fluorescence lifetimes of the powdered Eu(III) and Tb(III) complexes was 11.48 ms and 10.71 ms, respectively. The maximum emission intensity of the PNIPAM-Eu(III) complex at 613 nm and the PNIPAM-Tb(III) complex at 545 nm were enhanced about 11.1 and 11.3 times compared with that of the corresponding rare earth ions, respectively. Additionally, the lower critical solution temperature (LCST) of complexes were slightly higher than those of the copolymers. (C) 2013 Elsevier B.V. All rights reserved.
  • Chun-Hong Zhang, Hai-Lun Wang, Fang-Bin Liu, Xian-De Shen, Li-Jia Liu, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi, Yoshio Okamoto
    Acta Polymerica Sinica 6 811 - 816 2013年06月20日 [査読有り][通常論文]
     
    Three one-handed helical poly (phenylacetylene) derivatives bearing L-amino acid ethyl ester pendants, PPA-S-Phe, PPA-S-Leu and PPA-A-Leu were respectively synthesized by the polymerization of the corresponding monomers using Rh (nbd) BPh4 as a catalyst, and their chiral recognition abilities for seven racemates were evaluated as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) after coating them on silica gel. The difference between PPA-S-Phe and PPA-S-Leu is the chiral pendants. The chiral pendant of PPA-S-Phe is L-phenylalanine ethyl ester, while that of PPA-S-Leu is L-leucine ethyl ester. The difference between PPA-S-Leu and PPA-A-Leu is the linkage groups between polymer main chains and chiral pendants. The linkage of PPA-S-Leu is sulphonamide group,while that of PPA-A-Leu is amide group. PPA-S-Phe, PPA-S-Leu and PPA-A-Leu possess their characteristic helical conformation and show their characteristic chiral recognition depending on the chiral pendants and the linkage groups. When linkage is a sulphonamide group, PPA-S-Leu with L-leucine ethyl ester pendants shows higher chiral recognition abilities than PPA-S-Phe with L-phenylalanine ethyl ester pendants. When chiral pendant is L-leucine ethyl ester, PPA-A-Leu with amide linkage shows higher chiral recognition abilities than PPA-S-Leu with sulphonamide linkage. It is concluded that the linkage groups play an important role in chiral recognition as well as the chiral pendants.
  • Makiguchi, K, Kikuchi, S, Satoh, T, Kakuchi, T
    J. Polym. Sci., Part A Polym. Chem. 51 11 2455 - 2463 2013年06月 [査読有り][通常論文]
     
    The ring-opening polymerization (ROP) of cyclic esters, such as ε-caprolactone, 1,5-dioxepan-2-one, and racemic lactide using the combination of 3-phenyl-1-propanol as the initiator and triflimide (HNTf 2) as the catalyst at room temperature with the [monomer] 0/[initiator]0 ratio of 50/1 was investigated. The polymerizations homogeneously proceeded to afford poly(ε-caprolactone) (PCL), poly(1,5-dioxepan-2-one) (PDXO), and polylactide (PLA) with controlled molecular weights and narrow polydispersity indices. The molecular weight determined from an 1H NMR analysis (PCL, Mn,NMR = 5380 PDXO, Mn,NMR = 5820 PLA, Mn,NMR = 6490) showed good agreement with the calculated values. The 1H NMR and matrix-assisted laser desorption ionization time-of-flight mass spectrometry analyses strongly indicated that the obtained compounds were the desired polyesters. The kinetic measurements confirmed the controlled/living nature for the HNTf 2-catalyzed ROP of cyclic esters. A series of functional alcohols, such as propargyl alcohol, 6-azido-1-hexanol, N-(2-hydroxyethyl)maleimide, 5-hexen-1-ol, and 2-hydroxyethyl methacrylate, successfully produced end-functionalized polyesters. In addition, poly(ethylene glycol)-block- polyester, poly(δ-valerolactone)-block-poly(ε-caprolactone), and poly(ε-caprolactone)-block-polylactide were synthesized using the HNTf 2-catalyzed ROP. © 2013 Wiley Periodicals, Inc.
  • Decheng Wan, Toshifumi Satoh
    Encapsulation Nanotechnologies 225 - 253 2013年05月28日 [査読有り][通常論文]
     
    A highly specific supramolecular entrapment is traditionally and exclusively promoted by specific noncovalent interactions. This strategy is limited to two aspects: the guest species are limited to those which are topologically or electronically featured and the hosts have to be meticulously tailored in terms of size, morphology and electronic motif. Therefore, the host synthesis is tedious and challenging, and the spectrum of wellrecognizable guest species is narrow. In this chapter, it is shown that the derivatives of a hyperbranched polymer (mainly hyperbranched polyethylenimine (PEI)) can encapsulate a variety of guest species, and the encapsulating system shows a rather high guest selectivity in which a specific interaction is absent or very weak. It is known that a complex system tends to deviate from linearity. The nonlinear property of a supramolecular system implies that the appropriate combination of nonspecific elementary interactions possibly results in a high guest selectivity Experiments have shown that with the electronic engineering of a PEI-based nanocapsule, its guest affinity can be switched, the guest selectivity can be improved, and the guest releasing behavior becomes adjustable. It was found that 100% charge selective separation could be a general case, and effective separation of many anionic mixtures was also possible. These features of PEI-based nanocapsules have been employed for mixture separation and controlled guest release. The unimolecularity of a nanocapsule can also be enhanced by core engineering. © 2013 Scrivener Publishing LLC. All rights reserved.
  • Takuya Isono, Kensuke Kamoshida, Yusuke Satoh, Toshimitsu Takaoka, Shin-Ichiro Sato, Toshifumi Satoh, Toyoji Kakuchi
    Macromolecules 46 10 3841 - 3849 2013年05月28日 [査読有り][通常論文]
     
    The synthesis of well-defined four-armed star-shaped poly(butylene oxide) and figure-eight-shaped poly(butylene oxide)s (s-PBO and 8-PBO, respectively) with predicted molecular weights and narrow molecular weight distributions (Mw/Mns) was achieved by the t-Bu-P4-catalyzed ring-opening polymerization (ROP) of butylene oxide (BO). The t-Bu-P 4-catalyzed ROP of BO using 1,2,4,5-benzenetetramethanol as the initiator produced s-PBOs having number-average molecular weights (M n,NMRs) ranging from ca. 4000 to 12 000 g mol-1 and narrow Mw/Mns of < 1.03. Cleavage of the linkage between the initiator residue and PBO arms in s-PBO provided evidence for the homogeneous growth of each arm during the polymerization. The synthesis of 8-PBO was carried out through three reaction steps including (1) the synthesis of a PBO possessing two azido groups at the chain center ((N3) 2-(PBO)2) by the ROP of BO using 2,2-bis((6-azidohexyloxy) methy)propane-1,3-diol as the initiator, (2) the introduction of an ethynyl group at the two ω-chain ends by etherification using propargyl bromide to give the ω,ω′-diethynyl poly(butylene oxide) with two azido groups ((N3)2-(PBO-C≡CH)2), and (3) the intramolecular click cyclization of (N3)2-(PBO-C≡CH) 2 using the copper(I) bromide/N,N,N′,N″,N″- pentamethyldiethylenetriamine catalyst in DMF under high dilution conditions. Size exclusion chromatography, FT-IR, and 1H NMR measurements confirmed that the click reaction proceeded in an intramolecular fashion to give 8-PBOs having Mn,NMRs ranging from ca. 3000 to 12 000 g mol -1 and narrow Mw/Mns of < 1.06. The viscosity property of s-PBO and 8-PBO was evaluated together with linear and cyclic PBOs (l-PBO and c-PBO, respectively). The intrinsic viscosity ([η]) of l-PBO, c-PBO, s-PBO, and 8-PBO decreased in the order of l-PBO > s-PBO > c-PBO > 8-PBO. © 2013 American Chemical Society.
  • Chunhong Zhang, Fangbin Liu, Yufa Li, Xiande Shen, Xiaodong Xu, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi, Yoshio Okamoto
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 51 10 2271 - 2278 2013年05月 [査読有り][通常論文]
     
    Stereoregular poly(phenylacetylene) derivatives bearing L-leucine ethyl ester pendants, poly-1 and poly-2a, were, respectively, synthesized by the polymerization of N-(4-ethynylphenylcarbamoyl)-L-leucine ethyl ester (1) and N-(4-ethynylphenyl-carbonyl)-L-leucine ethyl ester (2) using Rh(nbd)BPh4 as a catalyst, while stereoirregular poly-2b was synthesized by solid-state thermal polymerization of 2. Their chiral recognition abilities for nine racemates were evaluated as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) after coating them on silica gel. Both poly-1 and poly-2a with a helical conformation showed their characteristic recognition depending on coating solvents and the linkage groups between poly(phenylacetylene) and L-leucine ethyl ester pendants. Poly-2a with a shorter amide linkage showed higher chiral recognition than poly-1 with a longer urea linkage. Coating solvents played an important role in the chiral recognition of both poly-1 and poly-2a due to the different conformation of the polymer main chains induced by the solvents. A few racemates were effectively resolved on the poly-2a coated with a MeOH/CHCl3 (3/7, v/v) mixture. The separation factors for these racemates were comparable to those obtained on the very popular CSPs derived from polysaccharide phenylcarbamates. Stereoirregular poly-2b exhibited much lower chiral recognition than the corresponding stereoregular, helical poly-2a, suggesting that the regular structure of poly(phenylacetylene) main chains is essential to attain high chiral recognition. (c) 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013, 51, 2271-2278
  • Guihua Cui, Yanhui Li, Tiantian Shi, Zhengguo Gao, Nannan Qiu, Toshifumi Satoh, Toyoji Kakuchi, Qian Duan
    CARBOHYDRATE POLYMERS 94 1 77 - 81 2013年04月 [査読有り][通常論文]
     
    A series of thermo-responsive copolymers of poly(N-isopropylacrylamide) (PNIPAM) and cellulose were synthesized via atom transfer radical polymerization (ATRP) using N-isopropylacrylamide as the monomer, cellulose acetate as the initiator, and CuCl/tris(2-dimethylaminoethyl)amine (Me6TREN) as a catalytic system. The resulting polymers had a narrow range of polydispersity indexes 1.27-1.37, and molecular weights of 8600-17,300 g mol(-1). Novel functional complexes of cellulose-g-PNIPAM/Eu(III) with excellent thermosensitive and fluorescent properties were then formed by the chelation of copolymers and europium(III) ions. The maximum emission intensity of the complexes at 613 nm was enhanced by a factor of approximately 10 relative to that of the corresponding Eu(III) complexes. Additionally, the lower critical solution temperatures (LCSTs) of cellulose-g-PNIPAM/Eu(III) were slightly greater than those of the copolymers. (C) 2013 Elsevier Ltd. All rights reserved.
  • Kosuke Makiguchi, Yoshitaka Ogasawara, Seiya Kikuchi, Toshifumi Satoh, Toyoji Kakuchi
    Macromolecules 46 5 1772 - 1782 2013年03月12日 [査読有り][通常論文]
     
    The ring-opening polymerization (ROP) of cyclic carbonates with diphenyl phosphate (DPP) as the organocatalyst and 3-phenyl-1-propanol (PPA) as the initiator has been studied using trimethylene carbonate (TMC), 5,5-dimethyl-1,3-dioxan-2-one, 5,5-dibromomethyl-1,3-dioxan-2-one, 5-benzyloxy-1,3-dioxan-2-one, 5-methyl-5-allyloxycarbonyl-1,3-dioxan-2-one, and 5-methyl-5-propargyloxycarbonyl-1,3-dioxan-2-one. All the polymerizations proceeded without backbiting, decarboxylation, and transesterification reactions to afford polycarbonates having narrow polydispersity indices. In addition, 6-azido-1-hexanol, propargyl alcohol, and N-(2-hydroxyethyl)maleimide were used as functional initiators for the DPP-catalyzed ROP to produce the end-functionalized poly(trimethylene carbonate)s. For further modification of the azido end-functionlized polycarbonate, the macrocyclic poly(trimethylene carbonate) was synthesized by the intramolecular click cyclization of the α-azido, ω-ethynyl poly(trimethylene carbonate). The DPP-catalyzed ROP was applicable for the block copolymerization of TMC and δ-valerolactone or ε-caprolactone to afford poly(trimethylene carbonate)-block-poly(δ-valerolactone) and poly(trimethylene carbonate)-block-poly(ε-caprolactone), and for that of TMC and l-lactide using DPP coupled with 4-dimethylaminopyridine without quenching to produce poly(trimethylene carbonate)-block-poly(l-lactide). © 2013 American Chemical Society.
  • Toru Ichihashi, Toshifumi Satoh, Chihiro Sugimoto, Kiichi Kajino
    PLOS ONE 8 3 e60068  2013年03月 [査読有り][通常論文]
     
    Background: To induce potent epitope-specific T cell immunity by a peptide-based vaccine, epitope peptides must be delivered efficiently to antigen-presenting cells (APCs) in vivo. Therefore, selecting an appropriate peptide carrier is crucial for the development of an effective peptide vaccine. In this study, we explored new peptide carriers which show enhancement in cytotoxic T lymphocyte (CTL) induction capability. Methodology/Principal Findings: Data from an epitope-specific in vivo CTL assay revealed that phosphatidylserine (PS) has a potent adjuvant effect among candidate materials tested. Further analyses showed that PS-conjugated antigens were preferentially and efficiently captured by professional APCs, in particular, by CD11c(+)CD11b(+)MHCII(+) conventional dendritic cells (cDCs) compared to multilamellar liposome-conjugates or unconjugated antigens. In addition, PS demonstrated the stimulatory capacity of peptide-specific helper T cells in vivo. Conclusions/Significance: This work indicates that PS is the easily preparable efficient carrier with a simple structure that delivers antigen to professional APCs effectively and induce both helper and cytotoxic T cell responses in vivo. Therefore, PS is a promising novel adjuvant for T cell-inducing peptide vaccines.
  • Nao Xiao, Yougen Chen, Xiande Shen, Chunhong Zhang, Shigenobu Yano, Michael Gottschaldt, Ulrich S. Schubert, Toyoji Kakuchi, Toshifumi Satoh
    POLYMER JOURNAL 45 2 216 - 225 2013年02月 [査読有り][通常論文]
     
    A series of AB(2)-, ABC-, (AB)(2)-, A(2)B(2)- and ABCD-type miktoarm copolymer Ru(II) complexes was synthesized by a stepwise chelating method, which involved the first-step chelating reaction of Ru(II)(DMSO)(4)Cl-2 with a polymer-substituted 2-(1H-1,2,3-triazol-4-yl)pyridine (tapy) or 2,6-bis(1H-1,2,3-triazol-4-yl)pyridine (bitapy) ligand to produce a stable polymer Ru(I!) mono-complex, and a second-step chelating reaction of the polymer Ru(II) mono-complex with another tapy or bitapy ligand to afford the miktoarm copolymer Ru(II) complexes. In order to synthesize them, the polymer-substituted tapy and bitapy ligands were first prepared by the click reaction of azido-terminated polymers with 2-ethynylpyridine and 2,6-diethynylpyridine, respectively. The azido-terminated polystyrene (PS) and poly(n-butyl acrylate) (PBA) were prepared by the atom-transfer radical polymerizations of styrene and n-butyl acrylate using ethyl 2-bromoisobutyrate as the initiator, followed by the substitutions of their end bromines with an azido group, respectively. The azido-terminated poly(n-hexyl isocyanate) was prepared by the living coordination polymerization of n-hexyl isocyanate using dichloro(cyclopentadienyl)(6-azidohexyloxy)titanium that was prepared by mixing 6-azido-1-hexanol with trichloro(cyclopentadienyl)titanium before the polymerization. The azido-terminated poly(styrene oxide) and poly(epsilon-caprolactone) were synthesized by the controlled/living ring-opening polymerizations of epsilon-caprolactone using diphenyl phosphate as the catalyst and of styrene oxide using the phosphazene base of t-Bu-P-4 as the catalyst, respectively, in which 6-azido-1-hexanol was used as the initiator. Polymer Journal (2013) 45, 216-225; doi:10.1038/pj.2012.100; published online 13 June 2012
  • Takuya Isono, Issei Otsuka, Yohei Kondo, Sami Halila, Sebastien Fort, Cyrille Rochas, Toshifumi Satoh, Redouane Borsali, Toyoji Kakuchi
    MACROMOLECULES 46 4 1461 - 1469 2013年02月 [査読有り][通常論文]
     
    The AB(2)- and AB(3)-type miktoarm star copolymers consisting of maltoheptaose (MH, as A block) and poly(epsilon-caprolactone) (PCL, as B block), namely MH-b-(PCL)(2) and MH-b-(PCL)(3), were synthesized, and their nano-organization was characterized. The syntheses of MHb-(PCL)(2) and MH-b-(PCL)(3) were carried out through two reaction steps: (1) preparation of linear and three-branched PCLs bearing an azido group on the chain center (N-3-(PCL)(2) and N-3-(PCL)(3)) by the diphenyl phosphate-catalyzed ring-opening polymerization of epsilon-caprolactone (epsilon-CL) using azido-functionalized di- and triols (N-3-(OH)(2) and N-3-(OH)(3)) as the initiators and (2) the copper-catalyzed azide-alkyne cycloaddition of N-3-(PCL)(2) and N-3-(PCL)(3) with the ethynyl-functionalized MH. The miktoarm star copolymers having M-n for the PCL block of ca. 5000 (MH-b-(PCL2.5k)(2) and MH-b-(PCL1.7k)(3)) and 10 000 (MH-b-(PCL5k)(2) and MH-b-(PCL3.3k)(3)) were obtained with a very narrow polydispersity index of less than 1.05. Bulk samples of the four types of miktoarm star copolymers exhibited body centered cubic phases, as determined by small angle X-ray diffraction experiments. The domain spacing were determined to be 9.8 nm for MH-b-(PCL2.5k)(2), 8.8 nm for MH-b-(PCL1.7k)(3), 10.5 nm for MH-b-(PCL5k)(2), and 9.8 nm for MH-b-(PCL3.3k)(3), which were smaller than those of the corresponding linear diblock copolymers.
  • 牧口孝祐, 覚知豊次, 佐藤敏文
    有機合成化学協会誌 71 7 706 - 715 2013年 [査読無し][通常論文]
     
    In recent years, along with growing concern about green chemistry, organocatalysis have been developed as novel catalytic systems due to its metal free nature. Because of their low toxicity and high chemical stability, organocatalysts have increasingly replaced metal catalyzed organic reactions. In particular, ring-opening polymerization (ROP) of cyclic esters, cyclic carbonates, and epoxides proceeded in a controlled/living fashion with organocatalysts. Previously, Hedrick and Waymouth mainly reported various basic or nucleophilic catalysts for ROP of lactide, lactones and trimethylene carbonate. In addition, we newly revealed organic super bases are suitable catalysts for ROP of epoxides. On the other hand, we and some other researchers investigated Brønsted acid catalysts to produce polyester or polycarbonate. In this review, we introduce our and their challenges for ROP using organocatalysts.
  • Keita Fuchise, Yougen Chen, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER CHEMISTRY 4 16 4278 - 4291 2013年 [査読有り][通常論文]
     
    Group transfer polymerization (GTP) has been a minor research topic since the emergence of controlled/living radical polymerization methods in the mid-1990s, even though it is counted as one of the living polymerization methods. However, the performance of GTP has much improved in many aspects, such as catalytic activity, polymerizable monomers, molecular weight control, and polymer structures that can be synthesized, through the introduction of newly developed Lewis base/acid organocatalysts and novel initiators since 2007-2008. In this review article, recent progress in GTP brought about by organocatalysts is described.
  • Issei Otsuka, Takuya Isono, Cyrille Rochas, Sami Halila, Sebastien Fort, Toshifumi Satoh, Toyoji Kakuchi, Redouane Borsali
    ACS MACRO LETTERS 1 12 1379 - 1382 2012年12月 [査読有り][通常論文]
     
    To date, the feature size of microphase separation in block copolymers has been downsizing to 10 nm scale. However, morphological control for such a small feature is still a challenging task. The present Letter discusses a phase transition in a natural/synthetic "hybrid" block copolymer system based on an oligosaccharide and poly(e-caprolactone) via thermal annealing. Time-resolved small-angle X-ray scattering investigation as a function of temperature indicated the phase transition from hexagonally close-packed cylinder to body-centered cubic at 10 am scale. Atomic force microscope images of the block copolymer thin films annealed at different temperatures clearly confirmed the existence of these morphologies. The driving force of this phase transition (from cylinder to cubic) is the change of volume fraction of the block copolymer due to thermal caramelization.
  • Wonsang Kwon, Yecheol Rho, Kensuke Kamoshida, Kyung Ho Kwon, Youn Cheol Jeong, Jonghyun Kim, Hideki Misaka, Tae Joo Shin, Jehan Kim, Kwang-Woo Kim, Kyeong Sik Jin, Taihyun Chang, Heesoo Kim, Toshifumi Satoh, Toyoji Kakuchi, Moonhor Ree
    ADVANCED FUNCTIONAL MATERIALS 22 24 5194 - 5208 2012年12月 [査読有り][通常論文]
     
    Low-temperature anionic ring-opening homopolymerizations and copolymerizations of two glycidol derivatives (allyl glycidyl ether (AGE) and ethoxyethyl glycidyl ether (EEGE)) are studied using a metal-free catalyst system, 3-phenyl-1-propanol (PPA) (an initiator) and 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris-(dimethylamino)phosphoranylidenamino]-2?5,4?5-catenadi(phosphazene) (t-Bu-P4) (a promoter) in order to obtain well-defined functional linear polyethers and diblock copolymers. With the aid of the catalyst system, AGE is found to successfully undergo anionic ring-opening polymerization (ROP) even at room temperature (low reaction temperature) without any side reactions, producing well-defined linear AGE-homopolymer in a unimodal narrow molecular weight distribution. Under the same conditions, EEGE also undergoes polymerization, producing a linear EEGE-homopolymer in a unimodal narrow molecular-weight distribution. In this case, however, a side reaction (i.e., chain-transfer reaction) is found to occur at low levels during the early stages of polymerization. The chemical properties of the monomers in the context of the homopolymerization reactions are considered in the design of a protocol used to synthesize well-defined linear diblock copolyethers with a variety of compositions. The approach, anionic polymerization via the sequential step feed of AGE and EEGE as the first and second monomers, is found to be free from side reactions at room temperature. Each block of the obtained linear diblock copolymers undergoes selective deprotection to permit further chemical modification for selective functionalization. In addition, thermal properties and structures of the polymers and their post-modification products are examined. Overall, this study demonstrates that a low-temperature metal-free anionic ROP using the PPA/t-Bu-P4 catalyst system is suitable for the production of well-defined linear AGE-homopolymers and their diblock copolymers with the EEGE monomer, which are versatile and selectively functionalizable linear aliphatic polyether platforms for a variety of post-modifications, nanostructures, and their applications.
  • Priyank N. Shah, Joonkeun Min, Chang-Geun Chae, Naoki Nishikawa, Daichi Suemasa, Toyoji Kakuchi, Toshifumi Satoh, Jae-Suk Lee
    MACROMOLECULES 45 22 8961 - 8969 2012年11月 [査読有り][通常論文]
     
    Poly(n-hexyl isocyanate)s (PHICs) with chiral moieties at both ends of their polymeric chains were synthesized by living anionic polymerizations. Such PHICs. were synthesized using a bidirectional initiator (sodium naphthalenide (Na-Naph)) and terminated with a chiral acid chloride, (S)-2-acetoxypropionyl chloride ((S)-Ct). Na-Naph created a covalent linkage in the middle of the chains by radical radical coupling. PHICs containing a chiral moiety at both ends adopted conformations with an opposite helical sense in comparison with those PHICs that had the same chiral moiety at only one end of their chain. By observing these structural differences, it was hypothesized that such a "helicity inversion" occurred in the PHICs due to the covalent linkage in the middle of the chain. Therefore, to prove this assumption about helicity inversion, a comparison study of the helical behaviors between the PHIC with the chiral moiety at both ends and the PHIC with the chiral moiety at only one end was performed. The synthesized PHICs were characterized using size exclusion chromatography-multiangle laser light scattering (SEC MALLS), MALDI-TOF. mass spectrometry, NMR spectrometry, and circular dichroism (CD).
  • Ryosuke Sakai, Eric B. Barasa, Naoya Sakai, Shin-ichiro Sato, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 45 20 8221 - 8227 2012年10月 [査読有り][通常論文]
     
    A series of sulfonamide-conjugated poly-(phenylacetylene)s with various electron withdrawing and donating substituents were designed and synthesized in order to develop a novel colorimetric probe for anions in water. The UV-vis absorption measurements, which were performed in an organic solvent to provide fundamental insights into the anion detection properties of these polymers, clarified that the colorimetric response ability is highly enhanced by the incorporation of strong electron withdrawing groups (EWG). Sulfonamide-conjugated poly(phenylacetylene) with nitro groups, the strongest EWG, was therefore used for the detection of anions in an aqueous environment. In a solution containing up to 20% water, the polymer exhibited obvious color changes to anions including the biologically important carboxylates. On the basis of the NMR titration analysis, such a colorimetric response was confirmed to be based on the deprotonation event of the sulfonamide binding site, which was suggested to be essential for the detection of aqueous anions.
  • Kenji Takada, Keita Fuchise, Yougen Chen, Toshifumi Satoh, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 50 17 3560 - 3566 2012年09月 [査読有り][通常論文]
     
    The group transfer polymerization (GTP) of methyl acrylate (MA) was studied using pentafluorophenylbis(triflyl)methane (C6F5CHTf2) as the organocatalyst and 1-trimethylsiloxy-, 1-triethylsiloxy-, and 1-triisopropylsiloxy-1-methoxy-2-methyl-1-propene (MTSMe, MTSEt, and MTSiPr, respectively) as the initiators. The C6F5CHTf2-promoted GTP of MA using MTSiPr proceeded in a living nature to produce poly(methyl acrylate)s (PMAs) with controlled molecular weights and narrow molecular weight distributions, which allowed the synthesis of high-molecular-weight PMA with the number-average molecular weight (Mn(SEC)) of up to 108,000 and the polydispersity (Mw/Mn) of 1.07. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry measurement revealed that the obtained PMA possessed the chain end structure that originated from MTSiPr, showing that the C6F5CHTf2-promoted GTP of MA proceeded without any side reactions. In addition, the kinetic study and the postpolymerization experiment supported the living manner of the polymerization. Moreover, the block copolymerization of MA and n-butyl acrylate (nBA) smoothly proceeded to afford the well-defined PMA-block-poly(n-butyl acrylate) (PnBA). (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
  • Yougen Chen, Kenji Takada, Keita Fuchise, Toshifumi Satoh, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 50 16 3277 - 3285 2012年08月 [査読有り][通常論文]
     
    The N-(trimethylsilyl)bis(trifluoromethanesulfonyl)imide-catalyzed (Me3SiNTf2-catalyzed) group transfer polymerization (GTP) of methyl methacrylate (MMA) has been studied for synthesizing stereospecific star-shaped poly(methyl methacrylate)s (PMMAs). The catalytic property of Me3SiNTf2 for the GTP of MMA using 1-methoxy-1-trimethylsilyloxy-2-methyl-propene as the initiator was confirmed by a kinetic investigation and matrix-assisted laser desorption ionization time-of-flight mass spectrometry measurement. The initiating efficiency (f) of Me3SiNTf2 was 0.941.00, which was estimated by the value of Mn(calcd)/Mn(SEC). The Me3SiNTf2-catalyzed GTP of MMA was carried out using initiators possessing three, four, and six MTS groups (MTS3, MTS4, and MTS6, respectively) under the condition of [MMA]0/[MTS3, MTS4, or MTS6]0 = 120 at -55 degrees C. All the obtained PMMAs exhibited unimodal and narrow molecular weight distributions as Mw/Mns = 1.031.04 and the Mw(MALS)s of the 3-, 4-, and 6-armed star-shaped PMMAs (PMMA3, PMMA4, and PMMA6, respectively) were 12.9, 12.9, and 13.4 kgmol-1, respectively, which fairly agreed with the calculated Mw(calcd) values. The syndiotacticities, rrs, of PMMA3, PMMA4, and PMMA6 were in the range of 8789%. The stereoblock synthesis of PMMA3, PMMA4, and PMMA6 was performed by the first and second polymerizations at -55 and 45 degrees C; the rrs of the first and second PMMA blocks were 87.0, 87.0, and 86.0% and 65.0, 65.0, and 64.0%, respectively. The glass transition temperatures (Tgs) were 118.1, 115.8, and 111.5 degrees C for the respective syndiotactic-rich PMMA3, PMMA4, and PMMA6 and 111.5, 109.7, and 107.6 degrees C for the respective stereoblock ones. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
  • Keita Fuchise, Yougen Chen, Kenji Takada, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULAR CHEMISTRY AND PHYSICS 213 15 1604 - 1611 2012年08月 [査読有り][通常論文]
     
    The strong Bronsted acid-promoted group transfer polymerization (GTP) of N,N-dimethylacrylamide (DMAA) using trifluoromethanesulfonimide (Tf2NH) and 2,3,4,5,6-pentafluorophenyl-1,1-bis(trifluoromethanesulfonyl)methane (Tf2CHC6F5) was carried out to quantitatively evaluate the effect of the counter anions for the employed acid on the kinetics and the stereoregularity of the polymerization. The equilibrium constant for the monomer activation (K) and the rate constant for the propagation reaction (kp) were determined from the integrated rate equation derived from the presumed polymerization mechanism. Both of the constants for the polymerization using Tf2CHC6F5 were higher than those for Tf2NH. The activation parameters for the syndiotactic propagation were determined from the Fordham plot.
  • Chunhong Zhang, Hailun Wang, Guangdong Su, Ruiqi Li, Xiande Shen, Shuang Zhang, Qianqian Geng, Fangbin Liu, Issei Otsuka, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER INTERNATIONAL 61 7 1158 - 1162 2012年07月 [査読有り][通常論文]
     
    Chiral and racemic macromonomers with a polymerizable phenylacetylenyl end group (PA-PLLA and PA-PDLLA) were successfully synthesized through living ring-opening polymerization of chiral and racemic monomers (L-lactide and DL-lactide), respectively. Then the homopolymerization of PA-PLLA and PA-PDLLA was successfully carried out to give poly(PA-PLLA) and poly(PA-PDLLA), respectively. Chiroptical properties, hydrodynamic radii and micromorphologies of poly(PA-PLLA) and poly(PA-PDLLA) were analyzed via circular dichroism, dynamic light scattering and atomic force microscopy (AFM), and the conformation of the polymers is discussed. The results indicate that poly(PA-PLLA) induced Cotton effects with different intensities in various solvents, and its hydrodynamic radii and dispersity were also different in various solvents, while poly(PA-PDLLA) induced no Cotton effects and its hydrodynamic radii and dispersity were approximately the same in various solvents. Furthermore, a helical conformation of poly(PA-PLLA) and the random main chains of poly(PA-PDLLA) were observed by AFM. Therefore, it is concluded that poly(PA-PLLA) possesses a dynamic one-handed helical conformation in various solvents due to chiral poly(L-lactide) pendants, while poly(PA-PDLLA) possesses racemic main chains because of the racemic poly(DL-lactide) pendants. Copyright (c) 2012 Society of Chemical Industry
  • Toshifumi Satoh, Ryosuke Ihara, Daisuke Kawato, Naoki Nishikawa, Daichi Suemasa, Yohei Kondo, Keita Fuchise, Ryosuke Sakai, Toyoji Kakuchi
    MACROMOLECULES 45 9 3677 - 3686 2012年05月 [査読有り][通常論文]
     
    Well-defined clickable poly(n-hexyl isocyanate) (PHIC) with an azido or alkyne end group as rod-like building block has been prepared by the living coordination polymerization using organotitanium catalysts. The obtained clickable PHIC was subjected to the Cu-catalyzed azide/alkyne cycloaddition for the synthesis of well-defined macromolecular architectures based on PHIC as a rod polymer, e.g., PHIC-b-poly(N-isopropyl acrylamide) as rod-coil block copolymer and 4-arm star PHIC as a rod star polymer. Additionally, PHIC-b-poly(L-lactide) and PHIC-b-poly(epsilon-caprolactone) as novel rod coil block copolymers were respectively synthesized by the ring-opening polymerizations of L-lactide and epsilon-caprolactone initiated from hydroxyl end-functionalized PHIC. All products were characterized by H-1 NMR spectroscopy, MALDI-TOF mass spectrometry, and size exclusion chromatography equipped with multiangle laser light scattering and viscosity detectors.
  • Hideki Misaka, Eisuke Tamura, Kosuke Makiguchi, Kensuke Kamoshida, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 50 10 1941 - 1952 2012年05月 [査読有り][通常論文]
     
    For the living ring-opening polymerization (ROP) of epoxy monomers, the catalytic activity of organic superbases, tert-butylimino-tris(dimethylamino)phosphorane, 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2?5,4?5-catenadi(phosphazene), 2,8,9-triisobutyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane, and 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylidenamino]-2?5,4?5-catenadi(phosphazene) (t-Bu-P4), was confirmed. Among these superbases, only t-Bu-P4 showed catalytic activity for the ROP of 1,2-butylene oxide (BO) to afford poly(1,2-butylene oxide) (PBO) with predicted molecular weight and narrow molecular weight distribution. The results of the kinetic, post-polymerization experiments, and MALDI-TOF MS measurement revealed that the t-Bu-P4-catalyzed ROP of BO proceeded in a living manner in which the alcohol acted as the initiator. This alcohol/t-Bu-P4 system was applicable to the glycidol derivatives, such as benzyl glycidyl ether (BnGE) and t-butyl glycidyl ether, to afford well-defined protected polyglycidols. The a-functionalized polyethers could be obtained using different functionalized initiators, such as 4-vinylbenzyl alcohol, 5-hexen-1-ol, and 6-azide-1-hexanol. In addition, the well-defined cyclic-PBO and PBnGE were successfully synthesized using the combination of t-Bu-P4-catalyzed ROP and click cyclization. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
  • Ryosuke Sakai, Atsushi Nagai, Yasuyuki Tago, Shin-ichiro Sato, Yoshinobu Nishimura, Tatsuo Arai, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 45 10 4122 - 4127 2012年05月 [査読有り][通常論文]
     
    A rationally designed poly-(phenylenebutadiynylene) bearing urea functionalities (poly-1) was demonstrated to be a novel fluorescence turn-on probe for various anions. Poly-1 itself exhibits an extremely weak emission that was undetectable by the naked eye, whereas the fluorescence emission of poly-1 was significantly enhanced by the addition of anions. Based on the NMR, dynamic light scattering, and fluorescence decay measurements, the observed fluorescence turn-on response was determined to be realized by the fluorescence recovery based on the disassembly of the poly-1 aggregates, which was originally triggered by the anion recognition event at the urea units of poly-1.
  • Zhengguo Gao, Jinaying Liang, Xiangdong Tao, Yuan Cui, Toshifumi Satoh, Toyoji Kakuchi, Qian Duan
    Macromolecular Research 20 5 508 - 514 2012年05月01日 [査読有り][通常論文]
     
    Zinc(II) tetra-(2-chloropropionylamido) phthalocyanine (TAPcCl) was synthesized as the initiator for atom transfer radical polymerization (ATRP). Using CuBr/tris(2-dimethylaminoethyl)amine as the catalyst system, AT R P o f N-isopropylacrylamide (NIPAM) was performed to create a new star-shaped poly(N-isopropylacrylamide) (PNIPAM) with a zinc phthalocyanine core and PNIPAM arms (TAPc-PAM). The structures of the initiator and the polymers were characterized by means of Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. The polydispersity index obtained by gel permeation chromatography indicated that the molecular weight distribution was narrow. The lower critical solution temperatures (LCST) for the TAPc-PAM aqueous solutions measured using the turbidimetry method were increased due to incorporation of the phthalocyanine core and decreased as molecular weight increased. TAPc-PAM possessed photocatalytic activity, a finding that was verified by Rhodamine B degradation in the presence of hydrogen peroxide under visible light. Moreover, the catalytic efficiency was higher at its LCST, which encouraged reuse of the photocatalyst.
  • Chun-hong Zhang, Guang-dong Su, Hai-lun Wang, Li-li Zhang, Xian-de Shen, Jian-wei Bai, Toshifumi Satoh, Toyoji Kakuchi
    ACTA POLYMERICA SINICA 4 365 - 373 2012年04月 [査読有り][通常論文]
     
    Sonagashira coupling reaction between 4-bromobenzyl alcohol and trimethysilylacetylene was carried out and then the trimethylsilyl group was removed to give 4-ethynylbenzyl alcohol. Living ring-opening polymerization of lactide was performed under normal pressure and temperature by using DBU as a catalyst and 4-ethynylbenzyl alcohol as an initiator. H-1-NMR spectra and GPC were employed to characterize the chemical structure of the products and analyze the molecular weight and polydispersity. The results indicated that polylactide macromonmers bearing 4-ethynylbenzyloxy end group (PA-PLLA-3k, PA-PLLA-4k, PA-PDLA-3k, and PA-PDLA-4k) were successfully synthesized, and the molecular weight of the macromonmers was controlled effectively. Homopolymerization of the macromonomers was carried out by using [Rh(nbd)Cl](2)/Et3N as the catalyst to give poly(phenylacetylene)s with polylactide side chains (poly(PA-PLLA)-3k, poly(PA-PLLA)-4k, poly(PA-PDLA)-3k and poly(PA-PDLA)-4k). The poly(phenylacetylene)s were characterized by GPC, GPC-MALLS and H-1-NMR. The results indicated that poly(PA-PLLA) and poly(PA-PDLA) possess linear flexible chain with high molecular weight. CD and UV-Vis spectra of the poly(phenylacetylene)s showed that poly(PA-PLLA) and poly(PA-PDLA) main chains assuredly possess predominantly one-handed helical conformations, and the direction of Cotton effects was affected by the chirality of macromonomers. The direction of Cotton effects of the poly(phenylacetylene)s was the same when the chirality of macromonomers was the same, Cotton effects of the poly(phenylacetylene)s were reverse when the chirality of macromonomers was reverse. The intensity of Cotton effects was various in different solvents, this meant that the regularity of helical conformation of the poly(phenylacetylene) main chain was variable in different solvents. Moreover, the stability of helical conformation of poly(phenylacetylene) decreased with the increasing temperature.
  • Ryosuke Sakai, Atsushi Nagai, Yasuyuki Tago, Shin-ichiro Sato, Toshifumi Satoh, Toyoji Kakuchi
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 243 2012年03月 [査読有り][通常論文]
  • Naoya Sakai, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 243 2012年03月 [査読有り][通常論文]
  • Kenji Takada, Keita Fuchise, Toshifumi Satoh, Toyoji Kakuchi
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 243 2012年03月 [査読有り][通常論文]
  • Eri Yoshida, Takashi Kaneko, Toshifumi Satoh, Yusuf Menceloglu, Atsuyoshi Nakayama
    International Journal of Polymer Science 2012 2012年 [査読有り][通常論文]
  • Hideki Misaka, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 44 23 9099 - 9107 2011年12月 [査読無し][通常論文]
     
    The ring-opening polymerization (ROP) of styrene oxide (SO) was carried out using 3-phenyl-1-propanol (PPA) as the initiator and a phosphazene base, 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phospho oranylidenamino]-2 Lambda(5),4 Lambda(5)-catenadi(phosphazene) (t-Bu-P(4)), as the catalyst at room temperature. The polymerization proceeded in a living manner, which was confirmed by the kinetic and chain extension experiments, to produce the poly(styrene oxide) (PSO) with a controlled molecular weight (S200-21 800 g mol(-1)) and narrow molecular weight distribution (<1.14). The (1)H NMR and MALDI-TOF MS measurements of the obtained PSO dearly indicated the presence of the PPA residue at the chain end. In addition, the t-Bu-P(4)-catalyzed ROP of SO with functional initiators, such as 4-vinylbenzyl alcohol, 5-hexen-1-ol, 6-azide-1-hexanol, and 3-hydroxymethyl-3-methyloxetane, successfully afforded the corresponding end-functionalized PSO with precise molecular control. The t-Bu-P(4)-catalyzed ROP of SO proceeded throup the beta- and alpha-scissions as the main and minor ring-opening manners on the basis of the microstructure of the PSOs analyzed by the (13)C NMR measurement, which was clarified in the model reactions corresponding to the initiation and propagation. For the thermal analysis of PSO, the glass transition temperature and 5% weight loss temperature were found to be 34 and 310 degrees C, respectively.
  • Yougen Chen, Keita Fuchise, Atsushi Narumi, Seigou Kawaguchi, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 44 23 9091 - 9098 2011年12月 [査読無し][通常論文]
     
    The core-first synthesis of three-, four-, and six-armed star-shaped poly(methyl methacrylate)s (PMMAs) with predicted molecular weights and narrow molecular weight distributions (M(w)/M(n)s) was carried out by the t-BuP(4)-catalyzed group transfer polymerization (GTP) of methyl methacrylate (MMA) using the newly designed silyl enolates, such as 1,1,1-tris[2-methyl-1-(trimethylsilyloxy)prop-1-enyloxymethyl]propane (E(C(MTS)(3)), tetrakis{[2-niethyl-1-(trimethylsilyloxy)prop-1-enyloxy]methyl}methane (C(MTS)(4)), and bis{2,2,2-tris[2,methyl-1-(trimethylsilyloxy)prop-1-enyloxy]ethyl}ether (O-(C(MTS)(3))(2)), respectively. The absolute molecular weight (M(w)(MALS)) of the obtained polymers proportionally increased with the increasing [MMA](0)/[initiator](0) ratio, and the highest molecular weight was ca. 132 kg mol(-1). Characterizations for the star-shaped PMMAs were conducted by cleavage and intrinsic viscosity [eta] experiments. Cleavage experiments of the star-shaped PMMAs provided the evidence for homogeneous growth of the each arm in the t-Bu-P(4)-catalyzed GTP. The number of arm determined from the shrinking factors (g') of [eta] also supported the successful syntheses of the star-shaped polymers by the present core-first method. The versatility of this core-first method toward other methacrylic monomers was confirmed by the t-BuP4-catalyzed GTPs of allyl methacrylate (AMA), stearyl methacrylate (SMA), and 2-(dimethylamino)ethyl methacrylate (DMAEMA) using C(MTS)(4) as an initiator leading to well-defined star-shaped polymers.
  • Xuerong Han, Yasuharu Satoh, Toshifumi Satoh, Ken'ichiro Matsumoto, Toyoji Kakuchi, Seiichi Taguchi, Tohru Dairi, Masanobu Munekata, Kenji Tajima
    APPLIED MICROBIOLOGY AND BIOTECHNOLOGY 92 3 509 - 517 2011年11月 [査読無し][通常論文]
     
    A previously established improved two-phase reaction system has been applied to analyze the substrate specificities and polymerization activities of polyhydroxyalkanoate (PHA) synthases. We first analyzed the substrate specificity of propionate coenzyme A (CoA) transferase and found that 2-hydroxybutyrate (2HB) was converted into its CoA derivative. Then, the synthesis of PHA incorporating 2HB was achieved by a wild-type class I PHA synthase from Ralstonia eutropha. The PHA synthase stereoselectively polymerized (R)-2HB, and the maximal molar ratio of 2HB in the polymer was 9 mol%. The yields and the molecular weights of the products were decreased with the increase of the (R)-2HB concentration in the reaction mixture. The weight-average molecular weight of the polymer incorporating 9 mol% 2HB was 1.00 x 10(5), and a unimodal peak with polydispersity of 3.1 was observed in the GPC chart. Thermal properties of the polymer incorporating 9 mol% 2HB were analyzed by DSC and TG-DTA. T (g), T (m), and T (d) (10%) were observed at -1.1A degrees C, 158.8A degrees C, and 252.7A degrees C, respectively. In general, major components of PHAs are 3-hydroxyalkanoates, and only engineered class II PHA synthases have been reported as enzymes having the ability to polymerize HA with the hydroxyl group at C2 position. Thus, this is the first report to demonstrate that wild-type class I PHA synthase was able to polymerize 2HB.
  • Xuerong Han, Yasuharu Satoh, Toshifumi Satoh, Ken'ichiro Matsumoto, Toyoji Kakuchi, Seiichi Taguchi, Tohru Dairi, Masanobu Munekata, Kenji Tajima
    APPLIED MICROBIOLOGY AND BIOTECHNOLOGY 92 3 509 - 517 2011年11月 [査読無し][通常論文]
     
    A previously established improved two-phase reaction system has been applied to analyze the substrate specificities and polymerization activities of polyhydroxyalkanoate (PHA) synthases. We first analyzed the substrate specificity of propionate coenzyme A (CoA) transferase and found that 2-hydroxybutyrate (2HB) was converted into its CoA derivative. Then, the synthesis of PHA incorporating 2HB was achieved by a wild-type class I PHA synthase from Ralstonia eutropha. The PHA synthase stereoselectively polymerized (R)-2HB, and the maximal molar ratio of 2HB in the polymer was 9 mol%. The yields and the molecular weights of the products were decreased with the increase of the (R)-2HB concentration in the reaction mixture. The weight-average molecular weight of the polymer incorporating 9 mol% 2HB was 1.00 x 10(5), and a unimodal peak with polydispersity of 3.1 was observed in the GPC chart. Thermal properties of the polymer incorporating 9 mol% 2HB were analyzed by DSC and TG-DTA. T (g), T (m), and T (d) (10%) were observed at -1.1A degrees C, 158.8A degrees C, and 252.7A degrees C, respectively. In general, major components of PHAs are 3-hydroxyalkanoates, and only engineered class II PHA synthases have been reported as enzymes having the ability to polymerize HA with the hydroxyl group at C2 position. Thus, this is the first report to demonstrate that wild-type class I PHA synthase was able to polymerize 2HB.
  • Xiangdong Tao, Ran Zhang, Zhengguo Gao, Toshifumi Satoh, Toyoji Kakuchi, Qian Duan
    JOURNAL OF MATERIALS SCIENCE 46 19 6396 - 6401 2011年10月 [査読無し][通常論文]
     
    Poly(N-isopropylacrylamide) with aromatic end groups (Ar-PNIPAM) were synthesized by atom transfer radical polymerization of N-isopropylacrylamide in isopropanol using phenyl 2-chloropropionate, (4'-phenyl) phenyl 2-chloropropionate, and (2',6'-diphenyl) phenyl 2-chloropropionate as initiators and CuCl/tris(2-dimethyl-aminoethyl) amine (Me(6)TREN) as a catalytic system. The resulting polymers had narrow polydispersity index of 1.10-1.14 and molecular weights of 3700-4600 g mol(-1). Then, novel functional complexes of Ar-PNIPAM, Europium(III) (Eu(III)), and alpha-Thenoyltrifluoroacetone (TTA) (Ar-PNIPAM/Eu(III)/TTA) with thermosensitive and fluorescent properties were synthesized and characterized by Fourier transform infrared spectra and fluorescence spectroscopy. Metal Eu(III) was not only bonded to oxygen and nitrogen atoms of polymer chain in PNIPAM, but also bonded to TTA. The maximum emission intensity of the complexes at 613 nm was enhanced about 22, 27, 33 times compared with that of the corresponding Eu(III). The lower critical solution temperatures (LCSTs) of Ar-PNI-PAM/Eu(III)/TTA were slightly greater compared with that of PNIPAM. Eu(III) complexes had excellent fluorescence performance, the fluorescence spectrum presented characteristic emission of Eu(III) at 613 nm.
  • Chunhong Zhang, Fangbin Liu, Qianqian Geng, Shuang Zhang, Xiande Shen, Ryohei Kakuchi, Hideki Misaka, Toyoji Kakuchi, Toshifumi Satoh, Ryosuke Sakai
    EUROPEAN POLYMER JOURNAL 47 10 1923 - 1930 2011年10月 [査読有り][通常論文]
     
    The living ring-opening polymerization of L-lactide was carried out by using organocatalyst to synthesize the molecular weight controlled poly(L-lactide) with an phenylacetylenyl end group (HC C-PLLA), then the homopolymerization of HC C-PLLA was performed by using two different rhodium catalysts. Low molecular weight poly-PLLA(6)-1 (M(W,SEC). (MALLS) = 46,700) was synthesized by using Rh(nbd)BPh(4) as the catalyst, and higher molecular weight poly-PLLA(6)-2 (M(W,SEC-MALLS) = 471,000) was synthesized by using the [Rh(nbd)Cl](2)/ Et(3)N catalyst system. Then high molecular weight poly-PLLA(20), poly-PLLA(29), and polyPLLA(68) were successfully synthesized by using the [Rh(nbd)Cl](2)/Et(3)N catalyst system. The a values of the poly-PLLAs using [Rh(nbd)Cl](2)/Et(3)N catalyst system were all in the range of 0.6-0.8, this means that these polymers possess linear flexible chain. It is concluded that [Rh(nbd)Cl](2)/Et(3)N was more suitable for the synthesis of the cylindrical polymer brush, poly-PLLA with high molecular weight. The analyses of the CD spectra indicated that poly-PLLA possesses a predominantly one-handed helical conformation, temperature and solvents had significant influences on the helical structure of poly-PLLA. (C) 2011 Elsevier Ltd. All rights reserved.
  • Xiangdong Tao, Ran Zhang, Zhengguo Gao, Toshifumi Satoh, Toyoji Kakuchi, Qian Duan
    JOURNAL OF MATERIALS SCIENCE 46 19 6396 - 6401 2011年10月 [査読無し][通常論文]
     
    Poly(N-isopropylacrylamide) with aromatic end groups (Ar-PNIPAM) were synthesized by atom transfer radical polymerization of N-isopropylacrylamide in isopropanol using phenyl 2-chloropropionate, (4'-phenyl) phenyl 2-chloropropionate, and (2',6'-diphenyl) phenyl 2-chloropropionate as initiators and CuCl/tris(2-dimethyl-aminoethyl) amine (Me(6)TREN) as a catalytic system. The resulting polymers had narrow polydispersity index of 1.10-1.14 and molecular weights of 3700-4600 g mol(-1). Then, novel functional complexes of Ar-PNIPAM, Europium(III) (Eu(III)), and alpha-Thenoyltrifluoroacetone (TTA) (Ar-PNIPAM/Eu(III)/TTA) with thermosensitive and fluorescent properties were synthesized and characterized by Fourier transform infrared spectra and fluorescence spectroscopy. Metal Eu(III) was not only bonded to oxygen and nitrogen atoms of polymer chain in PNIPAM, but also bonded to TTA. The maximum emission intensity of the complexes at 613 nm was enhanced about 22, 27, 33 times compared with that of the corresponding Eu(III). The lower critical solution temperatures (LCSTs) of Ar-PNI-PAM/Eu(III)/TTA were slightly greater compared with that of PNIPAM. Eu(III) complexes had excellent fluorescence performance, the fluorescence spectrum presented characteristic emission of Eu(III) at 613 nm.
  • Kosuke Makiguchi, Toshifumi Satoh, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 49 17 3769 - 3777 2011年09月 [査読無し][通常論文]
     
    The ring-opening polymerizations (ROPs) of epsilon-caprolactone (epsilon-CL) and delta-valerolactone (delta-VL) with pentafluorophenyl-bis(triflyl)methane (C(6)F(5)CHTf(2)) as the organocatalyst and alcohol initiators were carried out. For the ROP using 3-phenyl-1-propanol (PPA) as the initiator in CH(2)Cl(2) at room temperature with the [epsilon-CL or delta-VL](0)/[PPA](0)/[C(6)F(5)CHTf(2)] ratio of 50/1/0.1, the polymerization homogeneously proceeded to afford poly(epsilon-caprolactone) (PCL) and poly(delta-valerolactone) (PVL) having narrow polydispersity indices. The molecular weights of the obtained polymers determined from (1)H NMR spectra showed good agreement with those estimated from the initial ratio of [epsilon-CL or delta-VL](0)/[PPA](0) and monomer conversions. The (1)H NMR, size exclusion chromatography, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry measurements strongly indicated that PCL and PVL possessed the 3-phenylpropoxy group as the alpha-chain-end and the hydroxy group as the omega-chain-end. In addition, the controlled/living nature for the C(6)F(5)CHTf(2)-catalyzed ROP of lactones was confirmed by kinetic and chain-extension experiments. The block copolymerization of PCL and PVL successfully proceeded to afford PCL-b-PVL and PVL-b-PCL. In addition, various end-functionalized PCLs and PVLs with narrow molecular weight distributions were synthesized by the ROP of epsilon-CL and delta-VL using functional initiators, such as 6-azido-1-hexanol, 2-hydroxyethyl methacrylate, propargyl alcohol, N-(2-hydroxyethyl)maleimide, 4-vinylbenzyl alcohol, 5-hexen-1-ol, and 5-norbornene-2-methanol. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 3769-3777, 2011
  • Nguyen To Hoai, Akiyoshi Sasaki, Masahide Sasaki, Harumi Kaga, Toyoji Kakuchi, Toshifumi Satoh
    CARBOHYDRATE RESEARCH 346 13 1747 - 1751 2011年09月 [査読無し][通常論文]
     
    The dehydration of D-mannose and the demethanolization of methyl-alpha-D-mannopyranoside (M alpha MP) or methyl-alpha-D-mannofuranoside (M alpha MF) were examined using microwave-assisted heating for a 3-min irradiation at temperature from 120 to 280 degrees C in ordinary or dry sulfolane without any catalyst. The microwave-assisted heating of MaMP and M alpha MF smoothly proceeded to selectively afford the anhydromannoses, 1,6-anhydro-beta-D-mannopyranose (AMP) and 1,6-anhydro-beta-D-mannofuranose (AMF), respectively, in high yields. For MaMP in ordinary sulfolane at 240 degrees C, AMP was selectively obtained in the AMF: AMP ratio of 4: 96, whereas AMF was the major product at the AMF: AMP ratio of 97: 3 from M alpha MF in dry sulfolane at 220 degrees C. (C) 2011 Elsevier Ltd. All rights reserved.
  • Decheng Wan, Feng Chen, Toyoji Kakuchi, Toshifumi Satoh
    POLYMER 52 15 3405 - 3412 2011年07月 [査読無し][通常論文]
     
    The guest release and solution behavior during shell disruption of a polymeric nanocapsule are described. Hyperbranched polyethylenimine (PEI, M(n) = 10 000) is chemically functionalized with multiple DAD hydrogen-bonding motifs (D and A: hydrogen-bonding donor and acceptor), leading to PEI(232)-(DAD)(x) (3) (x = 93 (3a), x = 46 (3b), x = 23 (3c), x = 12 (3d)). Meanwhile, polyethylene oxide (M(n) = 2 200) is end-capped with thymine moieties (PEO-ADA) (4). Mixing of the hydrogen-bonding complementary 3 and 4 (DAD/ADA = 1) leads to a physical micelle (3.4) in apolar media, and the resulting micelle can completely and irreversibly transfer the ionic and water-soluble Congo red (CR) into chloroform phase by encapsulation. Experiment proves that the micelle can exist as a pseudo-unimolecular micelle (p-UIM, meaning one PEI in one micelle) or as aggregate, depending on the shell density. As a result, 3b.4 generally exists as a p-UIM while 3d.4 can exist as p-UIM only in a very narrow range of concentrations. The critical aggregation concentration (CAC) is also dependent on the core structure of the micelle, thus when the residual amines in the core of 3b are transformed into amide, the resulting 5b.4 shows a very low CAC. Small chemicals bearing DAD hydrogen-bonding motif can compete to bind with the PEO-ADA shell and destruct the p-UIM, leading to aggregation and precipitation of the p-UIM along with the CRs. Experiment proves that the CR has strong acid base interaction with the PEI core of the p-UIM, but when the basicity of the PEI core is reduced by amidation, partial CRs can be released into the water phase. (C) 2011 Elsevier Ltd. All rights reserved.
  • Takuya Isono, Toshifumi Satoh, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 49 14 3184 - 3192 2011年07月 [査読無し][通常論文]
     
    The one-pot synthesis of a main chain-type polyrotaxane composed of axle molecules threaded through the macrocyclic units on the polymer main chain was achieved via the combination of cyclopolymerization and clipping procedures. The cyclopolymerization of an a, x-diethynyl monomer bearing an isophthalamide moiety (1), which clips onto an axle component bearing a pyridiniumdicarboxamide moiety (2 center dot Cl) through a chloride anion was carried out in chloroform with the monomer concentration of 0.06 mol L-1 at 40 degrees C using [Rh(nbd)Cl](2)/Et3N as a catalyst to afford a gel-free polymer. The resulting polymer was assigned to the main chain-type polyrotaxane with a poly(phenylacetylene) backbone (poly-3 center dot Cl) based on size exclusion chromatography and H-1 NMR measurements. The diffusion-order two-dimensional NMR and circular dichroism spectra provided definitive proof of the rotaxaned architecture in the polymer. The mole fraction of the rotaxane unit in the total cyclic repeating unit was determined to be 26.3%. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 3184-3192, 2011
  • Toyoji Kakuchi, Yougen Chen, Junsuke Kitakado, Kota Mori, Keita Fuchise, Toshifumi Satoh
    MACROMOLECULES 44 12 4641 - 4647 2011年06月 [査読無し][通常論文]
     
    Organic superbases, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), proazaphosphatranes (P(RNCH2CH2)(3)-N: R = CH3, TMP; R = i-Bu, TiBP), and phosphazene bases (1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2 Lambda(5),4 Lambda(5)- catenadi(phosphazene), t-Bu-P-2; 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylidenamino]-2 Lambda(5),4 Lambda(5)-catenadi(phosphazene), t-Bu-P-4) were employed to determine the catalytic activity in the group transfer polymerization (GTP) of methyl methacrylate (MMA). Among the superbases used, TiBP and t-Bu-P-4 effectively catalyzed the polymerization to afford poly(methyl methacrylate) (PMMA) with controlled molecular weight and narrow polydispersity. In particular, the molecular weight of the PMMA obtained from the r-Bu-P-4-catalyzed GTP was up to 109 600 g mol(-1). Only one series of peaks was observed in the MALDI-TOF MS spectra of the PMMAs obtained from the TiBP- and t-Bu-P-4-catalyzed GTPs, indicating that both polymerizations proceeded without any side reactions. A postpolymerization experiment further supported the living nature of the TiBP- and t-Bu-P-4-catalyzed GTPs of MMA. Furthermore, a mechanistic study of the TiBP- and t-Bu-P-4-catalyzed GTPs of MMA was attempted by determining the stereoregularity of the obtained PMMAs and obtaining a series of NMR spectra for the equimolar mixtures of MTS and TiBP or t-Bu-P-4.
  • Ryosuke Sakai, Naoya Sakai, Toshifumi Satoh, Wen Li, Afang Zhang, Toyoji Kakuchi
    MACROMOLECULES 44 11 4249 - 4257 2011年06月 [査読有り][通常論文]
     
    Poly(phenylacetylene) bearing second generation lysine dendrons through urea groups (poly-2) was demonstrated to be a superior anion receptor possessing strict size specificity in colorimetric anion detection. On the basis of the comparison of the colorimetric response behavior between poly-2 and poly-1, which is poly(phenylacetylene) bearing first generation lysine dendrons, the size of the pendant dendron was implied to dictate the selectivity in the colorimetric anion detection. Various instrumental analyses including H-1 NMR, light scattering, and viscosity measurements concluded that the conjugation of the bulky G2 dendrons in the vicinity of the urea receptors plays a crucial role in imparting the strict size specificity in the anion-sensing ability of poly-2.
  • Toshifumi Satoh, Masaki Tamaki, Tsukasa Taguchi, Hideki Misaka, Nguyen To Hoai, Ryosuke Sakai, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 49 11 2353 - 2365 2011年06月 [査読有り][通常論文]
     
    The cationic ring-opening multibranching polymerization of 2-hydroxymethyloxetane (1) as a novel latent AB(2)-type monomer was carried out using trifluoromethane sulfonic acid or trifluoroboron diethyl etherate by a slow-monomer-addition (SMA) method. The polymer yield of poly-1 ranged from ca. 58-88%, which increase with the increasing monomer addition time on the SMA method. The absolute molecular weights (M-w,M-MALLS) and the polydispersities of poly-1 were in the range of 8,000-43,500 and 1.45-4.53, respectively, which also increased with the increasing monomer addition time. The Mark-Houwink-Sakurada exponents alpha in 0.2 M NaNO3 aq. were determined to be 0.02-0.25 for poly-1, indicating that poly-1 has compact forms in the solution because of the highly branched structure. The degree of the branching value of poly-1, which was calculated by Frey's equation, ranged from ca. 0.50 to 0.58, which increased with the increasing monomer addition time. The steady shear flow of poly-1 in aqueous solution exhibited a Newtonian behavior with steady shear viscosities independent of the shear rate. The results of the MALLS, NMR, and viscosity measurements indicated that poly-1 is composed of a highly branched structure, i.e., the hyperbranched poly (2-hydroxymethyloxetane). (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2353-2365, 2011
  • Toyoji Kakuchi, Yougen Chen, Junsuke Kitakado, Kota Mori, Keita Fuchise, Toshifumi Satoh
    MACROMOLECULES 44 12 4641 - 4647 2011年06月 [査読無し][通常論文]
     
    Organic superbases, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), proazaphosphatranes (P(RNCH2CH2)(3)-N: R = CH3, TMP; R = i-Bu, TiBP), and phosphazene bases (1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2 Lambda(5),4 Lambda(5)- catenadi(phosphazene), t-Bu-P-2; 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylidenamino]-2 Lambda(5),4 Lambda(5)-catenadi(phosphazene), t-Bu-P-4) were employed to determine the catalytic activity in the group transfer polymerization (GTP) of methyl methacrylate (MMA). Among the superbases used, TiBP and t-Bu-P-4 effectively catalyzed the polymerization to afford poly(methyl methacrylate) (PMMA) with controlled molecular weight and narrow polydispersity. In particular, the molecular weight of the PMMA obtained from the r-Bu-P-4-catalyzed GTP was up to 109 600 g mol(-1). Only one series of peaks was observed in the MALDI-TOF MS spectra of the PMMAs obtained from the TiBP- and t-Bu-P-4-catalyzed GTPs, indicating that both polymerizations proceeded without any side reactions. A postpolymerization experiment further supported the living nature of the TiBP- and t-Bu-P-4-catalyzed GTPs of MMA. Furthermore, a mechanistic study of the TiBP- and t-Bu-P-4-catalyzed GTPs of MMA was attempted by determining the stereoregularity of the obtained PMMAs and obtaining a series of NMR spectra for the equimolar mixtures of MTS and TiBP or t-Bu-P-4.
  • Toshifumi Satoh, Toyoji Kakuchi
    Complex Macromolecular Architectures: Synthesis, Characterization, and Self-Assembly 195 - 227 2011年05月03日 [査読有り][通常論文]
     
    The synthesis of novel hyperbranched glyco-conjugated polymers, prepared by the ring-opening multibranching polymerizations of anhydro and dianhydro sugars, is described. The hyperbranched glyco-conjugated polymers were formed by the cationic polymerization of 1,6-anhydro-β-D-hexopyranose, 1,4-anhydrotetritol, 2,3-anhydrotetritol, and 1,2:5,6-dianhydro-D-mannitol. These polymerizations proceeded without gelation to produce water-soluble hyperbranched glyco-conjugated polymers with controlled molecular weights and narrow polydispersities. This chapter also details the preparation and encapsulation-release property of novel amphiphilic hyperbranched polymers with a micellar characteristic as a single molecule, which are referred to as a 'unimolecular micelle' or 'unimolecular nanocapsule'. The amphiphilic hyperbranched polymers consisting of a hydrophilic hyperbranched glyco-conjugated polymer core and hydrophobic shell possessed an encapsulation ability for hydrophilic guest molecules and the controlled release property of the encapsulated guest molecules, e.g. the biodegradable unimolecular reversed micelle consisting of a hyperbranched D-mannan core and a poly(L-lactide) shell, and the pH-sensitive unimolecular reversed micelle consisting of a hyperbranched D-glucan core and L-leucine ethyl ether shell. © 2011 John Wiley & Sons (Asia) Pte Ltd.
  • Nguyen To Hoai, Akiyoshi Sasaki, Masahide Sasaki, Harumi Kaga, Toyoji Kakuchi, Toshifumi Satoh
    BIOMACROMOLECULES 12 5 1891 - 1899 2011年05月 [査読有り][通常論文]
     
    1,6-Anhydro-D-hexofuranoses, such as 1,6-anhydro-beta-D-glucofuranose (1), 1,6-anhydro-beta-D-mannofuranose (2), and 1,6-anhydro-alpha-D-galactofuranose (3), were polymerized using a thermally induced cationic catalyst in dry propylene carbonate to afford hyperbranched polysaccharides (poly1-3) with degrees of branching from 0.40 to 0.46. The weight-average molecular weights of polyl - 3 measured by multiangle laser light scattering varied in the range from (1.02 to 5.84) x 10(4) g.mol(-1), which were significantly higher than those measured by size exclusion chromatography. The intrinsic viscosities ([eta]) of poly1 - 3 were very low in the range from 4.9 to 7.4 mL.g(-1). The exponent (alpha) in the Mark-Houkwink-Sakurada equation ([eta] = KM(alpha)) of the polymers was 0.20 to 0.33, which is < 0.5. The steady shear flow of poly1 - 3 in an aqueous solution exhibited a Newtonian behavior with steady shear viscosities independent of the shear rate. These viscosity characteristics were attributed to the spherical structures of hyperbranched polysaccharides in an aqueous solution. Poly1 - 3 contained a high portion of terminal units of 31-43 mol % nonreducing D-hexopyranosyl and D-hexofuranosyl units, in which the D-hexofuranosyl units were 20-44 mol %. Moreover, polyl and poly2 showed a strong interaction to Concanavalin A due to the cluster effect or multivalent effect of numerous nonreducing saccharide units on their surfaces with binding constants in the range from 1.7 x 10(4) to 2.7 x 10(5) M(-1).
  • MAKIGUCHI Kosuke, SATOH Toshifumi, KAKUCHI Toyoji
    Macromolecules 44 7 1999 - 2005 2011年04月 [査読有り][通常論文]
     
    The ring-opening polymerization of delta-valerolactone (delta-VL) and epsilon-caprolactone (epsilon-CL) using 3-phenyl-1-propanol (PPA) as the initiator and dipheny phosphate (DPP) as the catalyst in toluence at room temperature with the [delta-VL or epsilon-CL](0)/[PPA](0)/[DPP] ratio of 50/1/1 homogeneously proceeded to afford poly(delta-valerolactone) (PVL) and poly(epsilon-caprolactone) (PCL) with narrow polydispersity indices. The molecular weights determined from a (1)H NMR analysis (PVL, M(n,NMR) = 5170 g mol(-1) and PCL, M(n,NMR =) 5920 g mol(-1)) showed good agreement with those estimated from the initial of [delta-VL or epsilon-CL](0)/[PPA] and monomer conversions (PVL, M(n,theo) = 4890 g mol(-1) and PCL, M(n,theo) = 5680 g mol(-1)). The (1)H NMR, SEC, and MALDI-TOF MS measurements of the obtained PVL and PCL clearly indicated the presence of the initiator residue at the chain end, confirming that the DPP-catalyzed ROP of lactones proceeded through a activated monomer mechanishm. The kinectic and chain extension experiments confirmed the controlled/living nature for the DPP-catalyzed ROP of lactones. In addition, the block copolymerization of PVL and PCL successfully proceeded to afford PVL-b-PCL regardless of the monomer additon sequence. The DPP-catalyzed ROP of delta-VL and epsilon-CL using functional initiators, such as 2-hydroxyethyl methacrylate, 4-vinylbenzyl alcohol, propargyl alcohol, and 6-azido-1-hexanol, produced the corresponding end-functionalized PVLs and PCLs with narrow molecular weight distributions.
  • Fumi Shozui, Ken'ichiro Matsumoto, Ren Motohashi, Jian Sun, Toshifumi Satoh, Toyoji Kakuchi, Seiichi Taguchi
    POLYMER DEGRADATION AND STABILITY 96 4 499 - 504 2011年04月 [査読有り][通常論文]
     
    A poly(lactic acid) (PLA)-like terpolyester consisting of 96 mol% lactate (LA). I mol% 3-hydroxybutyrate and 3 mol% 3-hydroxyvalerate was produced in recombinant Escherichia coli LS5218 expressing LA-polymerizing enzyme (LPE). The strain was grown on glucose with a feeding of valerate as the monomer precursor. The glass transition and melting temperatures of the terpolyester were close to those of chemically synthesized poly(L-LA)s (PLLAs) having similar molecular weights. Additionally, a blend of the terpolyester, which was composed entirely of (R)-LA (D-LA) due to the strict enantiospecificity of LPE, with PLLA formed a stereocomplex with higher melting temperature (201.9 degrees C). These results indicate that the biological PLA-like polyester produced via this one-step microbial process has comparable thermal properties to chemically synthesized PLAs. (C) 2011 Elsevier Ltd. All rights reserved.
  • Hideki Misaka, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 241 2011年03月 [査読有り][通常論文]
  • Naoya Sakai, Ryosuke Sakai, Toshifumi Satoh, Afang Zhang, Toyoji Kakuchi
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 241 2011年03月 [査読有り][通常論文]
  • Chunhong Zhang, Xiande Shen, Ryosuke Sakai, Michael Gottschaldt, Ulrich S. Schubert, Shiho Hirohara, Masao Tanihara, Shigenobu Yano, Makoto Obata, Nao Xiao, Toshifumi Satoh, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 49 3 746 - 753 2011年02月 [査読有り][通常論文]
     
    Metal template synthesis is a useful methodology to make sophisticated macromolecular architectures because of the variety of metal ion coordination. To use metal template methodology, chelating functionalities should be introduced to macromolecules before complexation. In this article, we demonstrate the click-to-chelate approach to install chelating functionality to polystyrene (PS) and complexation with Ru(II) ions to form 3-arm and 4-arm star-branched PS Ru(II) complexes. Azide-terminated PS (PS-N-3) was readily prepared by atom transfer radical polymerization using 1-bromoethylbenzene as an initiator followed by substitution of bromine by an azide group. The Cu(I)-catalyzed 1,3-dipolar cycloaddition of PS-N-3 with 2-ethynylpyridine or 2,6-diethynylpyridine affords 2-(1H-1,2,3-triazol-4-yl)pyridine (PS-tapy) or 2,6-bis(1H-1,2,3-triazol-4-yl)pyridine (PS-bitapy) ligands bearing one or two PS chains at the first-position of the triazole rings. Ru(II) complexes of PS-tapy and PS-bitapy were prepared by conventional procedure. The number-averaged molecular weights (M(n)s) of these complexes were determined to be 6740 and 10,400, respectively, by size exclusion chromatography using PS standards. These M-n values indicated the formation of 3-arm and 4-arm star-branched PS Ru(II) complexes [Ru(PS-tapy)(3)](PF6)(2) and [Ru(PS-bitapy)(2)](PF6)(2) on the basis of the M-n values of PS-tapy (2090) and PS-bitapy (4970). The structures of these complexes were also confirmed by UV-vis spectroscopy and X-ray crystallography of the Ru(II) complexes [Ru(Bn-tapy)(3)](PF6)(2) and [Ru(Bn-bitapy)(2)](PF6)(2), which bear a benzyl group instead of a PS chain. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 746-753, 2011
  • Decheng Wan, Shigeki Ohta, Toyoji Kakuchi, Toshifumi Satoh
    SOFT MATTER 7 14 6422 - 6425 2011年 [査読有り][通常論文]
     
    With beta-cyclodextrin inserted in the core, a completely hydrophilic nanocapsule (a hyperbranched polyethylenimine core with a poly (ethylene oxide) shell) can encapsulate hydrophobic pyrene with unique releasing properties: on-demand chemically triggered release and unprecedented sensitivity to pH value.
  • Xiangdong Tao, Zhengguo Gao, Toshifumi Satoh, Yuan Cui, Toyoji Kakuchi, Qian Duan
    POLYMER CHEMISTRY 2 9 2068 - 2073 2011年 [査読有り][通常論文]
     
    We synthesized a series of well-defined, stimuli-responsive diblock copolymers composed of poly(N-isopropylacrylamide) and poly(6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate) by atom transfer radical polymerization and click chemistry. The diblock copolymers were then characterized by nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and gel permeation chromatography. When the azobenzene content reached 4.5 mol%, the diblock copolymer became insoluble in water. The aqueous solutions of the polymers exhibited a lower critical solution temperature (LCST) that depended on the amount of incorporated azobenzene. Higher LCSTs were observed after UV irradiation, with a maximum difference of 4.1 degrees C for the copolymer containing 1.4 mol% azobenzene groups. The photochemical properties of the polymer were also studied by UV-vis spectroscopy.
  • Zhengguo Gao, Xiangdong Tao, Yuan Cui, Toshifumi Satoh, Toyoji Kakuchi, Qian Duan
    POLYMER CHEMISTRY 2 11 2590 - 2596 2011年 [査読有り][通常論文]
     
    A novel asymmetrical zinc(II) phthalocyanine (ZnPcBr) was synthesized as the initiator for atom transfer radical polymerization (ATRP). Using CuBr/tris(2-dimethylaminoethyl) amine (Me6TREN) as the catalyst system, the ATRP of N-isopropylacrylamide (NIPAM) was carried out to afford a new linear poly(N-isopropylacrylamide) with end group of asymmetrical phthalocyanine (ZnPc-PAM). The structures of the initiator and the polymers were characterized by means of FT-IR and H-1 NMR. Polydispersity index (PDI) obtained by gel permeation chromatography (GPC) indicated that the molecular weight distribution was narrow. The lower critical solution temperatures (LCST) for the aqueous solutions of ZnPc-PAM, measured by turbidimetry method and differential scanning calorimetry (DSC), respectively, were increased due to the incorporation of the phthalocyanine group at the chain end and lowered with increasing molecular weight. It was verified that ZnPc-PAM possessed photocatalytic activity by the degradation of Rhodamine B in the presence of hydrogen peroxide under visible light. Moreover, it presented the highest catalytic efficiency at around its LCST owing to the thermo-sensitive property, which benefited the recycling of the polymeric photocatalyst.
  • Ryosuke Sakai, Shota Okade, Eric B. Barasa, Ryohei Kakuchi, Magdalena Ziabka, Satoshi Umeda, Katsuyuki Tsuda, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 43 18 7406 - 7411 2010年09月 [査読有り][通常論文]
     
    Poly(phenylacetylene) with rationally designed urea groups was demonstrated to be a superior anion receptor possessing both a calorimetric response ability and a positive homotropic allosteric binding mode. The target polymer, poly(phenylacetylene) with [bis(trifluoromethyl)phenyflurea pendants (poly-1), was synthesized by the stereoselective polymerization with Rh(nbd)BPh(4) (nbd = norbornadiene) in high yield. The anion sensing ability of poly-1 was evaluated using the tetra-n-butylammonium (rBA) salts of a series of anions in TH F. Upon the addition of anions such as CH(3)CO(2)(-), C(6)H(5)CO(2)(-), F(-), Cl(-), Br(-), NO(3)(-), N(3)(-), and HSO(4)(-), the yellow color of the THF solution of poly-1 immediately turned to a different color depending on the types of anions, indicating the anion recognition capability of poly-1. The 111 NM R Otrations of poly-1 by using increasing amounts of CH(3)CO(2)(-) revealed that the colorimetric response of poly] was considered to be the direct consequence of the hydrogen-bonding complex formation between the urea functionality and the anions. Interestingly, during the course of the determination of the anion-binding affinity, we encountered highly cooperative binding ability of poly-1. The Hill plot analysis provided an exceptional positive cooperativity, e.g., 8.4 of Hill coefficient in the complexation between poly-I and C(6)H(5)CO(2)(-). This result clearly indicated that this binding mode was based on a positive homotropic altosterism, in which the partially formed urea/anion complex units in the polymer chain should produce a change in the whole main chain conformation, facilitating further anion binding. Additionally, by comparing the anion binding of poly-I with that of previously prepared urea-functionalized poly(phenylacetylene) (poly-2), an enhanced anion binding ability based on two electron-withdrawing -CF(3) groups was found to be essential to realize such cooperativity.
  • Ryohei Kakuchi, Yosuke Tsuji, Kaori Chiba, Keita Fuchise, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 43 17 7090 - 7094 2010年09月 [査読有り][通常論文]
     
    The polymerization of h-valerolactone (delta-VL) using 3-phenyl-1-propanol (3-Ph-PrOH) as the initiator and trifluoromethanesulfonimide (HNTf(2)) as the catalyst in CH(2)Cl(2) at 27 degrees C with the [delta-VL](0)/[3-Ph-PrOH](0)/[HNTf(2)](0) ratio of 100:1:0.1 proceeded homogeneously to afford a poly(delta-valerolactone) (PVL) with a narrow polydispersity index. The molecular weight determined from the (1)H NMR analysis, M(n) = 9600 g mol(-1) fairly agreed with that estimated from the initial ratio of [delta-VI](0)/[3-Ph-PrOH](0), M(n,theo) = 9400 g mol(-1). In addition, the kinetic and chain extension experiments confirmed that the HNTf(2)-catalyzed ROP proceeded in a living fashion. The (1)H NM R, SEC, and MALDI-TOF MS measurements of the obtained PVL clearly indicated the presence of the initiator residue at the chain end, showing that the HNTf(2)-catalyzed ROP of delta-VL proceeded through a living mechanism. The HNTf(2)-catalyzed ROP of delta-VL with functional initiators, such as 6-azido-1-hexanol, 2,3,4,5,6-pentafluorobenzyl alcohol, and N-(2-hydroxyethyl)maleimide, successfully afforded the corresponding end-functionalized PVL with a precise molecular control.
  • Keita Fuchise, Masako Sone, Yutaka Miura, Ryosuke Sakai, Atsushi Narumi, Shin-Ichiro Sato, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER JOURNAL 42 8 626 - 631 2010年08月 [査読有り][通常論文]
     
    1-Adamantyl methacrylate (AdMA) was polymerized using the atom transfer radical polymerization (ATRP) method with methyl alpha-bromoisobutyrate (MBiB), copper(I) bromide (CuBr), copper(II) bromide (CuBr(2)) and 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) in toluene at 60 degrees C, producing well-defined poly(1-adamantyl methacrylate) (PAdMA). Simultaneous control of the molecular weight and tacticity of PAdMA was successfully achieved by the ATRP method using the MBiB/CuBr/CuBr(2)/ tris[2-(dimethylamino)ethyl]amine-initiating system in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) at -20 degrees C. Block copolymerization of AdMA and methyl methacrylate (MMA) was successfully achieved by the poly(methyl methacrylate) macroinitiator/CuBr(2)/HMTETA/tin(II) 2-ethylhexanoate-initiating system based on activators generated by electron transfer (AGET) ATRP method. Differential scanning calorimetry revealed the relationship between the glass transition temperature, molecular weight and tacticity of the obtained PAdMA. Polymer Journal (2010) 42, 626-631; doi: 10.1038/pj.2010.55; published online 30 June 2010
  • Keita Fuchise, Atsushi Narumi, Ryosuke Sakai, Toshifumi Satoh, Seigou Kawaguchi, Toyoji Kakuchi
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 240 2010年08月 [査読有り][通常論文]
  • Keita Fuchise, Ryosuke Sakai, Toshifumi Satoh, Shin-ichiro Sato, Atsushi Narumi, Seigou Kawaguchi, Toyoji Kakuchi
    MACROMOLECULES 43 13 5589 - 5594 2010年07月 [査読有り][通常論文]
     
    The combination of (Z)-1-(dimethylammo)-1-ti imethylsiloxy- I -propene ((Z)-DATP) and Bronsted acid of trffluoromethanesulfonmnde (Tf(2)NH) was found to act as a highly efficient c-rp initiating system for N,N-chmethylmethacrylamide (DMAA) at 0 degrees C The Tf(2)NH-catalyzed GTP of DMAA initiated by (Z)-DATP proceeded in a lime, manner to pi duce poly(N,N-dimethylacrylamide)s (PDMAA) with controlled molecular weights and mu row molecular weight distributions The living nature was confirmed by measuiements and a postpolymei ization experiment Furthermore. the MALDI-TOF MS analysis revealed that the moleculai weight of the obtained PDMAA was in perfect agreement with that of PDMAA conta ming the (Z)-DATP initiator lesidue and the desdylated chain end, showing that the Tf(2)NH-catalyzed GTP of DMAA pi oceeded without any side reactions The obtained PDM AA was r diad rich and had up to 73% of r diad contents Glass transition tempei at tn es of PDMAA showed molecular weight dependence below 20 kg moI(-1)
  • Ryohei Kakuchi, Ryotaro Shimada, Yasuyuki Tago, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 48 8 1683 - 1689 2010年04月 [査読有り][通常論文]
     
    The colorimetric detection of anionic species has been studied for a-amino acid-conjugated poly(phenylacetylene)s, which were prepared by the polymerization of the ethyl esters of N-(4-ethynylphenylsulfonyl)-L-alanine, L-isoleueine, L-valine, L-phenylalanine, L-aspartic acid, and L-glutamic acid using Rh+(2,5-norbornadiene)[(eta(6)-C6H5)B-(C6H5)(3)) as the catalyst in CHCl3. The one-handed helical conformations of all the sulfonamide-functionalized polymers were characterized by Cotton effects in the circular dichroism spectra. The addition of anions with a relatively high basicity, such as tetra-n-butylammonium acetate and fluoride, induced drastic changes in both the optical and chiroptical properties. On the other hand, anions with a relatively low basicity, such as tetra-n-butylammonium nitrate, azide, and bromide, had essentially no effects on the helical conformation of all the sulfonamide-functionalized polymers. The anion signaling property of the sulfonamide-functionalized polymers possessing a-amino acid moieties was significantly affected by the installed residual amino acid structures. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1683-1689, 2010
  • Masaki Tamaki, Tsukasa Taguchi, Soichi Nakabayashi, Kota Mori, Yoshikazu Kitajyo, Ryosuke Sakai, Toyoji Kakuchi, Toshifumi Satoh
    POLYMER CHEMISTRY 1 1 82 - 92 2010年03月 [査読有り][通常論文]
     
    The ring-opening polymerization of 5,6-anhydro-1,2-O-isopropylidene-alpha-D-glucofuranose (1) as a latent cyclic AB(2)-type monomer was carried out using potassium tert-butoxide (t-BuOK) or boron trifluoride diethyletherate (BF(3).OEt(2)) as an initiator in order to synthesize a novel hyperbranched glycopolymer. The anionic and cationic polymerizations proceeded via the proton-transfer reaction mechanism to produce the hyperbranched poly(5,6-anhydro-1,2-O-isopropylidene-alpha-D-glucofuranose) (2). In particular, the cationic polymerization with the slow-monomer-addition strategy is a facile method leading to the hyperbranched glycopolymers with high molecular weights and highly branched structures. The weight-average molecular weight (M(w.SEC).MALLs) values of 2 measured by multi-angle laser light scattering (MALLS) varied in the range from 7400 to 122 400, which were significantly higher than the weight-average molecular weight (M(w.SEC)) values determined by size exclusion chromatography (SEC). The intrinsic viscosities ([n]) of these polymers were very low in the range of 3.3-4.6 mL g(-1) and the Mark-Houwink-Sakurada exponents, alpha, were calculated to be 0.08-0.27. These results of the MALLS. SEC, and viscosity measurements suggested that these polymers exist in a compact spherical conformation in solution because of their highly branched structure. The synthesis of the hyperbranched 5,6-glucan (3) by hydrolysis of polymer 2 was also demonstrated. Polymer 3 is a novel water-soluble hyperbranched glycopolymer arranged with numerous reducing D-glucose units on the peripheries of the polymer, and has a higher reducing ability than D-glucose because of the glycocluster effect or the multivalent effect of the reducing D-glucose units. Therefore, polymer 3 should be called a "reducing sugar ball".
  • Ryosuke Sakai, Takafumi Yonekawa, Issei Otsuka, Ryohei Kakuchi, Toshifumi Satoh, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 48 5 1197 - 1206 2010年03月 [査読有り][通常論文]
     
    Diacetylene monomers with respective lengths of the oxyethylene chains were cyclopolymerized with a rhodium catalyst to produce novel poly(phenylacetylene)s bearing a different cavity size of the chiral crown ether in the repeating units (2a-c). In the circular dichroism spectra of the resulting polymers, characteristic Cotton effects were observed in the range from 350 to 500 nm corresponding to the absorption of the conjugated polymer backbone, indicating that the polymers possessed a helical structure with an excess single screw sense induced by the covalently bonded binaphthyl units. The host-guest complexation of 2a-c with achiral guests produced a chiroptical change based on the fluctuation in the main chain conformation. The behavior of the complexation-induced chiroptical change was essentially dictated by the cavity size of the binaphthocrown ether units. Additionally, a chirality-responsive helicity change was observed in the case of the complexation of 2a-c with chiral guests, which also depended on the crown ether size. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1197-1206, 2010
  • Kenji Takahashi, Hiroaki Tezuka, Shingo Kitamura, Toshifumi Satoh, Ryuzi Katoh
    PHYSICAL CHEMISTRY CHEMICAL PHYSICS 12 8 1963 - 1970 2010年 [査読有り][通常論文]
     
    The photochemistry of the benzophenone ketyl radical in D(1) excited state, BPH(D(1)), was studied by means of two-color dual-pulse laser flash photolysis (355 and 532 nm) in a room-temperature ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (Bmim-TFSA), and in methanol. Upon excitation with the 532 nm pulse, BPH(D(1)) emitted strong fluorescence. The transient absorption and fluorescence spectra of BPH(D(1)) were measured with nanosecond and sub-nanosecond time resolution, respectively. The observed Stokes shift was 1700 cm(-1) in Bmim-TFSA, and this shift was close to that in acetonitrile. The fluorescence lifetime of BPH(D(1)) was determined to be 5 ns in Bmim-TFSA, and again the value was close to that in acetonitrile. The rate constant of the reaction of BPH(D(1)) with CCl(4) in Bmim-TFSA was determined to be (2.1 +/- 0.4) x 10(9) M(-1) s(-1), which was 10 times the rate constant calculated on the basis of the bulk viscosity of Bmim-TFSA. The results are discussed in terms of the effective microscopic viscosity of the ionic liquid that was recently reported for the cage effect.
  • Hiroe Satoh, Momoko Hayashi, Toshifumi Satoh, Toyoji Kakuchi, Harumi Kaga, Kenji Takahashi
    IONIC LIQUID APPLICATIONS: PHARMACEUTICALS, THERAPEUTICS, AND BIOTECHNOLOGY 1038 1038 145 - 154 2010年 [査読無し][通常論文]
     
    It is known that some ionic liquids can dissolve cellulose, and that ionic liquids can be heated very rapidly using microwave irradiation. These characteristics make it possible to use ionic liquids as a reaction medium to form anhydrosugars from polysaccharides by microwave irradiation. In the present study, we examined formation of anhydroglucose from "glucose, cellobiose, and cellulose using microwave irradiation in several ionic liquids. A single-mode microwave was used to carry out the reactions. The yield of anhydroglucose from cellobiose was quite high: a 60 mol% yield at 270 degrees C after 4 min of heating time. It has also been found that in the ionic liquids, diethyl-methyl-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide and butylmethyl imidazolium bis(trifluoromethanesulfonyl)imide, a few products were obtained from depolymerization of cellulose and cellobiose. The main products were identified as 1,6-anhydro-beta-D-glucopyranose and 1,6-anhydro-beta-D-glucofuranose. In contrast, in the ionic liquid butyl-methylimidazolium chloride after a few minutes of microwave heating, the samples turned dark brown; no anhydrosugars were produced. These results suggest the importance of proper selection of the anion in the ionic liquids to produce anhydrosugars.
  • Hiroe Satoh, Harumi Kaga, Toyoji Kakuchi, Toshifumi Satoh, Kenji Takahashi
    CHEMISTRY LETTERS 38 12 1178 - 1179 2009年12月 [査読無し][通常論文]
     
    it is found that the dehydration of glucose to anhydroglucose, such as 1,6-anhydro-beta-D-glucopyranose and 1,6-anhydro-beta-D-glucofuranose, proceeds very effectively in hydrophobic ionic liquids, for example ionic liquid N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium bis(trifluoromethanesulfonyl)amide, without any catalysts at high temperature. On the other hand, addition of a small amount of an ionic liquid with chloride anion reduces the yield of the anhydroglucose significantly.
  • Masaki Tamaki, Tsukasa Taguchi, Yoshikazu Kitajyo, Kenji Takahashi, Ryosuke Sakai, Toyoji Kakuchi, Toshifumi Satoh
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 47 24 7032 - 7042 2009年12月 [査読無し][通常論文]
     
    A hyperbranched polyglycerol bearing imidazolium. tosylate units (ITHB) was synthesized through the imidazolium salt-modification of hyperbranched polyglycerol (HB). ITHB was found to possess novel reversible lower critical solution temperature (LCST)-type liquid-liquid and liquid-solid phase transition behaviors in a methanol/chloroform mixed solution The phase transition temperatures of the liquid-liquid phase transition (PTT(1to2)) and liquid-solid phase transition (PTT(2toSus)) increased with increasing the ratio of methanol in the mixed solution and decreasing the concentration of ITHB. Additionally, increasing the molecular weight of ITHB decreased the PTT values. The liquid-liquid phase transition was caused by the aggregation of ITHB, which was proved by dynamic light scattering measurement. In contrast, the liquid-solid phase transition was caused by the solvation cleavage between the imidazolium. rings and solvents, which was proved by (1)H NMR measurement. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A Polym Chem 47, 7032-7042, 2009
  • Kenji Takahashi, Hiroe Satoh, Toshifumi Satoh, Toyoji Kakuchi, Masakatsu Miura, Akiyoshi Sasaki, Masahide Sasaki, Harumi Kaga
    CHEMICAL ENGINEERING JOURNAL 153 1-3 170 - 174 2009年11月 [査読無し][通常論文]
     
    The application of high temperature water to produce levoglucosan from glucose was studied. The reactions were performed using a tube reactor, and the kinetics for the decomposition Of glucose and levoglucosan in high temperature water was examined. The temperature dependence of the reaction rate of the glucose decomposition was of the Arrhenius type. In contrast, the reaction rates for the decomposition of levoglucosan decreased with the increasing temperature at the constant pressure of 25 MPa. The yields of levoglucosan were examined in the temperature range from 200 to 410 degrees C and the pressure from 5 to 25 MPa. It was found that the yields of levoglucosan increased with the decreasing pressure. (C) 2009 Elsevier B.V. All rights reserved.
  • Keita Fuchise, Ryohei Kakuchi, Sung-Tso Lin, Ryosuke Sakai, Shin-Ichiro Sato, Toshifumi Satoh, Wen-Chang Chen, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 47 22 6259 - 6268 2009年11月 [査読無し][通常論文]
     
    The precise synthesis and variation in the thermoresponsive property based on the supramolecular assembly of a novel urea end-functionalized poly(N-isopropylacrylamide) (PNIPAM) were studied. A series of PNIPAMs with different diphenylurea groups at the chain end (X-Ph-NH-CO-NH-Ph-trz-PNIPAM.: X = H, OCH(3), CH(3), NO(2), Cl, and CF(3)) were synthesized by using a combination of the atom transfer radical polymerization and the copper(I)-catalyzed azide-alkyne cycloaddition. The cloud point of the obtained polymers depended on the hydrogen-bonding ability of the introduced urea group. The (1)H NMR measurement suggested that the obtained PNIPAM assembled in water via the intermolecular hydrogen bonding by the terminal urea group. From the dynamic light scattering and transmission electron microscopy measurements, the aggregated nanoparticles of the resulting polymer were directly observed in water at a temperature below its cloud point. The hydrogen-bonding property of the chain end urea group was concluded to be involved in the aggregation of the PNIPAM in water, leading to the variation in its cloud point. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6259-6268, 2009
  • Ryohei Kakuchi, Kaori Chiba, Keita Fuchise, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 42 22 8747 - 8750 2009年11月 [査読有り][通常論文]
     
    The Bronsted acid, trifluoromethanesulfonimide (HNTf(2)), was revealed to act as a highly efficient activator for group transfer polymerization (GTP) of methyl methacrylate (MMA) at ambient temperature. The HNTf(2)-catalyzed GTP of MMA initiated by 1-methoxy-1-trimethylsilyloxy-2-methylpropene (MTS) proceeded in a living manner to produce poly(methyl methacrylate)s (PMMA) with controlled molecular weights and narrow molecular weight distributions. Kinetic measurement and post-polymerization experiment further supported that the polymerization proceeded in a living fashion. Furthermore, from the MALDI-TOF MS analysis, only one series of peaks was observed, which was in perfect agreement with the molecular weight of PMMA possessing the MTS initiator residue and the desilylated chain end, showing that the HNTf(2)-catalyzed GTP of MMA proceeded without any side reactions. The syndiotacticity of the PMMA obtained by the HNTf(2)-catalyzed GTP increased with the decreasing polymerization temperature the syndiotactic (rr) triad content was 72% at 27 degrees C and 90% at -55 degrees C.
  • Yougen Chen, Masako Sone, Keita Fuchise, Ryosuke Sakai, Ryohei Kakuchi, Qian Duan, Jingliang Sun, Atsushi Narumi, Toshifumi Satoh, Toyoji Kakuchi
    REACTIVE & FUNCTIONAL POLYMERS 69 7 463 - 469 2009年07月 [査読有り][通常論文]
     
    Well-defined diblock and triblock copolymers consisting of poly(N-isopropylacrylamide) (PNIPAM) and poly(N-hydroxyethylacrylamide) (PHEAA) were prepared using the atom transfer radical polymerization (ATRP) method. The number-average molecular weight and fraction of each segment were precisely controllable by adjusting the monomer/initiator ratio in feed. The lower critical solution temperature (LCST) of a series of block copolymers with different compositions was examined using a turbidimetry analysis. The copolymers with a relatively lower molar fraction of HEAA units in the polymer chain exhibited phase transition phenomenon, in which the LCST depended on the fraction in the copolymer. On the other hand, the LCST disappeared for the copolymers with higher HEAA unit molar fractions. The (1)H NMR measurement clarified that the disappearance of the LCST was attributed to the formation of the water-soluble micelle. Furthermore, the thermoresponsive property of the series of block copolymers was elucidated on the basis of the structural effect of the copolymer, which includes the order and length of the block segments. (C) 2008 Elsevier Ltd. All rights reserved.
  • Ryohei Kakuchi, Yasuyuki Tago, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 42 13 4430 - 4435 2009年07月 [査読無し][通常論文]
     
    A colorimetric detection of guest counteranions has been demonstrated using poly(phenylacetylenes)s with urea functionalities and alpha-amino acids, such as L-leucinie, L-glutamic acid, L-aspartic acid, L-phenylalanine, L-isoleucine, and L-alanine (PPA-Leu, PPA-Glu, PIIA-Asp, PPA-Phe, PPA-Ile, and PPA-Ala, respectively). The polymers were prepared by the polymerization of the N-(4-ethynylphenylcarbamoyl)-L-amino acids ethyl ester (PA-Leu, PA-Glu, PA-Asp, PA-Phe, PA-Ile, and PA-Ala) using Rh+(2,5-norbornadiene)[(eta(6)-C6H5)B-(C6H5)(3)] (Rh(nbd)BPh4) as the catalyst. The biased helical conformations of all the urea-functionalized polymers were demonstrated through Cotton effects in the circular dichroism (CD) spectra. The addition of various ammonium salts including tetra-n-butylammonium acetate (TBAA), benzoate (TBAB), nitrate (TBAN), azide (TBAN(3)), fluoride (TBAF), chloride (TBACl), and bromide (TBABr) to,I solution of all the urea-functionalized polymers intensified the CD responses of the polymers, indicative of the chiral adjustability of the anion recognition using urea groups. The anion signaling property of the urea-functionalized polymers was different from each other. In particular, the signs of the induced Cotton effect for the urea-functionalized polymers in the presence of anions were strongly dependent on the pendant Structure of the alpha-amino acids.
  • Hideki Misaka, Ryohei Kakuchi, Chunhong Zhang, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 42 14 5091 - 5096 2009年07月 [査読無し][通常論文]
     
    The living ring-opening polymerization of delta-valerolactone (VL) initiated from 6-azide-1-hexanol using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1-[3,5-bis(trifluoromethyl)phenyl]-3-cyclohexylthiourea (BCT) was carried out to prepare the poly(delta-valerolactone)s (N-3-PVL-OH) bearing azide groups at the cc-chain ends with M-n,M-NMRS (PDIs) of 2600 (1.08), 4700 (1.11), and 9900 (1.09). The acetylene functionality was introduced at the omega-end of N-3-PVL-OH using 5-hexynoyl chloride to afford the telechelic poly(delta-valerolactone) with the azide group at the alpha-end and acetylene group at the omega-end (N-3-PVL-C CH). The click reaction between the alpha-azide and the omega-acetylene of N-3-PVL-C CH in DMF was carried out under the highly diluted condition as [N-3-PVL-C CH] = 0.18 mM, which was monitored by IR and H-1 NMR measurements. The SEC peak of the cyclic-PVL shifted to the lower molecular weight region than that of N-3-PVL-C CH, and the intrinsic viscosity of the cyclic-PVL, significantly decreased. In addition, there was no change in the molecular weight of the resulting polymer through the click cyclization, which was confirmed on the basis of the MALDI-TOF M:S measurement. Finally, we succeeded in the synthesis of a well-defined cyclic-PVL having a narrow polydispersity (M-w/M-n = 1.09-1.15) and the predicted molecular weight (M-n,M-NMR = 2800-9500) in reasonable yield (60-80%) using the click cyclization.
  • Formation of levoglucosan from cellobiose in ionic liquids
    Yoshinori Nambu, Momoko Hayashi, Toshifumi Satoh, Toyoji Kakuchi, Hrumi Kaga, Kenji Takahashi
    3rd Congress on Ionic Liquids 1 page in CD-ROM  Proceedings of 3rd Congress on Ionic Liquids 2009年06月 [査読無し][通常論文]
  • Ryohei Kakuchi, Tatsuro Kodama, Ryotaro Shimada, Yasuyuki Tago, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 42 12 3892 - 3897 2009年06月 [査読無し][通常論文]
     
    Three-dimensionally organized sulfonamide groups have been demonstrated to show an anion signaling ability using poly(phenylacetylene) with L-aspartic acid and sulfonamide functionalities (poly-1). The polymerization of N-4-ethynylphenylsulfonyl)-L-aspartic acid diethyl ester (1) was carried out using Rh(+)(2,5-norbornadiene)[(eta(6)-C(6)H(5))B(-)(C(6)H(5))(3)] (Rh(nbd)BPh(4)) as a catalyst to afford poly-1. The biased helical conformation of poly-1 was demonstrated through Cotton effects in the circular dichroism (CD) spectra. The addition of the anions including perchlorate (ClO(4)(-)), nitrate (NO(3)(-)), azide (N(3)(-)), and bromide (Br(-)) anions had fundamentally no effect on both the CD and UV profiles of poly-1. On the other hand, the addition of the anions including acetate and fluoride anions (CH(3)COO(-) and F(-)) into the poly-1 solution intensified the CD responses of the poly-1, showing that the anion recognition of sulfonamide groups induced distinct changes in the poly(phenylacetylene) backbone. In addition, a distinct red shift was observed for poly-1 in the presence of these two anions; i.e., the lambda(max) value for CH(3)COO(-) changed from 408 to 447 nm, and that for F(-) changed from 408 to 482 nm. The guest specificity observed in the solution color change of poly-1 with counteranions clearly correlated with the guest basicity.
  • Manami Misu, Hidemitsu Furukawa, Hyuck-Joon Kwon, Kazuhiro Shikinaka, Akira Kakugo, Toshifumi Satoh, Yoshihito Osada, Jian Ping Gong
    JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A 89A 2 424 - 431 2009年05月 [査読無し][通常論文]
     
    We developed a novel in situ method for the control of F-actin assembly by using a synthetic photoresponsive polycation. The photoresponsive polycation mainly comprises a water-soluble cationic monomer and also contains a small amount of the monomer of a triphenylmethane leucohydroxide derivative (20 mol %), which is a well-known photochromic molecule that can be cationized in aqueous solution by ultra violet (UV) irradiation, thereby causing an increase in the total charge on the photoresponsive polycation. Thus, by exposure to UV radiation in aqueous solution, F-actin and the photoresponsive polycation start assembling into F-actin/photoresponsive polycation complexes of various morphologies Such as bundles, coils, and networks, depending upon the concentrations of both the F-actin and salt. Further, localized UV irradiation can be applied in order to control the local formation of F-actin/photoresponsive polycation complexes. Thus, this technique provides a novel method for the spatiotemporal control of F-actin assembly and can be applied to investigate the unknown characteristics of F-actin. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 89A: 424-431, 2009
  • Kenji Takahashi, Hiroaki Tezuka, Toshifumi Satoh, Yosuke Katsumura, Masayoshi Watanabe, Robert A. Crowell, James F. Wishart
    CHEMISTRY LETTERS 38 3 236 - 237 2009年03月 [査読無し][通常論文]
     
    The kinetic salt effect on the disproportionation reaction between diiodide anions in methanol has been examined using two ionic liquids and one inorganic salt. The ionic reaction was accelerated significantly, depending on the cation of the salt, and the ionic liquids enhanced the reaction more effectively. At higher concentrations the reaction rates decrease owing to increasing viscosities.
  • Kenji Tajima, Yasuharu Satoh, Toshifumi Satoh, Rumi Itoh, Xuerong Han, Seiichi Taguchi, Toyoji Kakuchi, Masanobu Munekata
    MACROMOLECULES 42 6 1985 - 1989 2009年03月 [査読無し][通常論文]
     
    In our previous paper, we synthesized poly-3-hydroxybutyrate [P(3HB)] by using the water-organic-solvent two-phase reaction system (TPRS), in which (R)-3-hydroxybutyrylCoA [(R)-3HBCoA] was continuously supplied to PHA synthase by the ester exchange reaction between CoA and thiophenol in thiophenyl (R)-3HB [(R)-3HBTP]. By applying TPRS to the screening, we found a lactate- (LA-) polymerizing enzyme from PHA synthases. The enzyme was an engineered PHA synthase, which stereoselectively copolymerized (R)-LA together with (R)-3HB. NMR and GPC revealed that the TPRS successfully synthesized poly(lactate-co-(3-hydroxybutyrate)) [P(LA-co-3HB)] using the LA-polymerizing enzyme as a catalyst. The molar ratios of LA in the copolymers were controllable in the range of 0 to 36 mol% by varying the ratio of (R)-LATP and (R)-3HBTP fed into the TPRS. The number-average molecular weight and the polydispersity of P(36 mol%-co-3HB) were 1.1 x 10(4) and 1.4, respectively. This is the first report on the chemo-enzymatic synthesis of P(LA-co-3HB) by a LA-polymerizing enzyme.
  • Ryohei Kakuchi, Sachiko Nagata, Yasuyuki Tago, Ryosuke Sakai, Issei Otsuka, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 42 5 1476 - 1481 2009年03月 [査読無し][通常論文]
     
    Three-dimensionally organized amide groups have been demonstrated to show a high sensitivity toward anionic guests using poly(phenylacetylene)s with L-leucine and amide functionalities (poly-PA-Leu). The poly-PA-Leu was prepared from the N-(4-ethynylphenylcarbonyl)-L-leucine ethyl ester (PA-Leu) using Rh(+)(2,5-norbornadiene)[(eta(6)-C(6)H(5))B(-)(C(6)H(5))(3)] (Rh(nbd)BPh(4)) as a catalyst. The biased helical conformation of poly-PA-Leu was demonstrated through Cotton effects in the circular dichroism (CD) spectra. The addition of ammonium salts including acetate, fluoride, benzoate, azide, and bromide (CH(3)COO(-), F(-). C(6)H(5)COO(-), N(3)(-), and Br(-), respectively) into the poly-PA-Leu solution intensified the CD responses of the poly-PA-Leu, indicative of the polyacetylene helicity changes triggered by anion recognition of the amide groups. The efficient anion binding was observed for poly-PA-Leu with CH(3)COO(-), whose apparent binding constant was estimated to be 1.1 x 10(3) (mol(-1).L). On the other hand, the anions including perchlorate (ClO(4)(-)), nitrate (NO(3)(-)), chloride (Cl(-)), and iodide (I(-)) had essentially no effects on both the CD and UV profiles of poly-PA-Leu. The guest specificity observed in the CD spectra of poly-PA-Leu with counteranions clearly correlated with the guest-basicity.
  • Atsushi Narumi, Yougen Chen, Masako Sone, Keita Fuchise, Ryosuke Sakai, Toshifumi Satoh, Qian Duan, Seigou Kawaguchi, Toyoji Kakuchi
    MACROMOLECULAR CHEMISTRY AND PHYSICS 210 5 349 - 358 2009年03月 [査読無し][通常論文]
     
    N-Hydroxyethylacrylamide (HEAA) was polymerized using the atom transfer radical polymerization (ATRP) with ethyl 2-chloropropionate (ECP), copper(I) chloride (CuCl), and tris[2-(dimethylamino)ethyl]amine (Me(6)TREN) in ethanol/water, producing poly(N-hydroxyethylacrylamide) (PHEAA) with well-defined molecular weights. The thermogravimetric analysis (TGA) indicated that the obtained PHEAA broadly decomposed with a two-stage weight loss. The first loss was due to the decomposition of the hydroxyethyl groups, which started at temperatures ranging from 249.2 to 277.1 degrees C. The remaining polyacrylamide backbones started to decompose at temperatures ranging from 352.5 to 383.4 degrees C. The differential scanning calorimetry (DSC) indicated that PHEAA had a glass transition temperature (T(g)) ranging from 70.6 to 117.8 degrees C. The ability of the obtained PHEAA as a prepolymer to initiate other acrylamide derivatives is described. N,N-Dimethylacrylamide (DMAA), N-acyloylmorpholine (NAM), and N-[3-(dimethylamino)propyl]acrylamide (DMAPAA) were subsequently added to the solutions after the polymerization of HEAA with ECP/CuCl/Me(6)TREN, producing the corresponding block copolymers.
  • Toshifumi Satoh, Yoshikazu Kitajyo, Ryosuke Sakai, Atsushi Narumi, Kenji Takahashi, Harumi Kaga, Noriaki Kaneko, Toyoji Kakuchi
    MACROMOLECULAR SYMPOSIA 279 1 145 - 150 2009年 [査読無し][通常論文]
     
    The synthesis of a unimolecular reverse micelle (3) consisting of hyperbranched D-glucan as the core and L-leucine ethyl ester as the shell was accomplished through the carbamation reaction of the hyperbranched D-glucan (1) with the N-carbonyl L-leucine ethyl ester (2) in pyridine at 100 degrees C. The polymer 3 was soluble in a large variety of organic solvents, such as methanol, acetone, chloroform, and ethyl acetate, and insoluble in water, which remarkably differed from the solubility of 1. The solubilities Of 3 were also changed by the substitution degrees of the L-leucine moiety. The encapsulation ability of 3 toward water-soluble dyes has been investigated. These results indicated that 3 was a unimolecular reverse micelle with an encapsulation ability toward hydrophilic dye molecules. in addition, 3 showed an molecular size-selective encapsulation ability.
  • Sung-Tso Lin, Keita Fuchise, Yougen Chen, Ryosuke Sakai, Toshifumi Satoh, Toyoji Kakuchi, Wen-Chang Chen
    SOFT MATTER 5 19 3761 - 3770 2009年 [査読無し][通常論文]
     
    New thermoresponsive conjugated rod-coil-coil triblock copolymers were successfully synthesized from terminal azido functionalized poly(N-isopropylacrylamide)-b-poly(N-hydroxyethylacrylamide) (PNIPAAm-b-PHEAA) and alkynyl functionalized polyfluorene (PF) via a click reaction. The azido functionalized PNIPAAm-b-PHEAA copolymers with different block ratio was prepared by atom transfer radical polymerization from an initiator bearing the azide group, whereas alkynyl functionalized PF was synthesized by Suzuki coupling reaction. The lower critical solution temperature (LCST) of the block copolymers increased with an enhanced hydrophilic PHEAA block ratio, since the longer PHEAA segment facilitated the copolymer chains to stretch at an elevated temperature. The micelles of PNIPAAm-b-PHEAA with different block ratio changed into spheres, aggregate spheres, vesicles, and wormlike micelles as the temperature was increased, due to the variation on the hydrophilic/hydrophobic characteristic of PNIPAAm. However, the micellar morphologies became worms, bundles of wormlike micelles, and hollow tubes in the triblock PF-b-PNIPAAm-b-PHEAA, which were probably induced by the pi-pi interaction among the fluorene segments. The variation of the micelle morphology with temperature was consistent from the results of transmission electron microscopy, atomic force microscopy, and dynamic light scattering. Also, the micelle morphologies of PF-b-PNIPAAm-b-PHEAA showed a thermoreversible property based on its LCST. The photoluminescence characteristics behaved as an on/off fluorescence indicator of temperature, showing an "on-off-on'' profile at an elevated temperature in water at a higher block ratio of PNIPAAm and switching to "on-off'' as the block ratio of PNIPAAm decreased. The present study suggests that the PF-b-PNIPAAm-b-PHEAA copolymers have tunable morphologies and could be potentially used as thermoresponsive sensory materials.
  • 佐藤敏文
    化学と工業 62 3 256 - 257 2009年 [査読無し][通常論文]
  • 佐藤敏文
    Bio Industry 26 8 50 - 57 シーエムシー出版 2009年 [査読無し][通常論文]
  • Toshifumi Satoh
    SOFT MATTER 5 10 1972 - 1982 2009年 [査読有り][通常論文]
     
    This Review article details the preparation and encapsulation-release properties of novel amphiphilic hyperbranched polymers with a micellar characteristic as a single molecule, which are referred to as "unimolecular micelles'' or "unimolecular nanocapsules''. Amphiphilic hyperbranched polymers consisting of a hydrophilic hyperbranched polycarbohydrate core and hydrophobic shell possess an ability to encapsulate hydrophilic guest molecules and control the release of the encapsulated guest molecules, e. g., a biodegradable unimolecular reversed micelle consisting of a hyperbranched D-mannan core and a poly(L-lactide) shell, and the pH-sensitive unimolecular reversed micelle consisting of a hyperbranched D-glucan core and L-leucine ethyl ether shell. An amphiphilic hyperbranched polymer consisting of a hyperbranched polythreitol as the hydrophilic core and trityl groups as the hydrophobic shell acts as unimolecular nanocapsule, and shows a high encapsulation ability for guest molecules. Amphiphilic hyperbranched polymer with a hydrophobic core and hydrophilic L-aspartic acid shell possess encapsulation properties for hydrophobic molecules in water. Hence, hyperbranched polymers are found to be good candidates for the dendritic core molecule of a unimolecular micelle or unimolecular nanocapsule.
  • Osamu Nishizawa, Hideki Misaka, Ryosuke Sakai, Toyoji Kakuchi, Toshifumi Satoh
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 46 22 7411 - 7418 2008年11月 [査読無し][通常論文]
     
    The copolymerization of ethylene (E) and norbornene (NB) was investigated using the commercially available and inexpensive catalyst system, cyclopentadienylzirconium trichloride (CpZrCl3)/isobutyl-modified methylaluminoxane (MMAO), at a moderate polymerization temperature in toluene. For the CpZrCl3 catalyst system activated by aluminoxane with a 40 mol % methyl group and a 60 mol % isobutyl group (MMAO), the quantities of the charged NB and the polymerization temperature significantly affected the molecular weights, polydispersities, and NB contents of the obtained copolymers and the copolymerization activities in all the experiments. As the charged NB increased and thereby the NB/E molar ratio increased, the NB content in the copolymer increased and reached a maximum value of 71 mol %. The CpZrCl3/MMAO ([A1]/[Zr] = 1000) catalyst system with the [NB] of 2.77 mol L-1 and ethylene of 0.70 MPa at 50 degrees C showed the highest activity of 1690 kg mol(zr)(-1) h(-1) and molecular weight of 21,100 g mol(-1). The C-13 NMR analysis showed that the CpZrCl3/MMAO catalyst system produced the E-NB random copolymer with a number of NB homosequences such as the NN dyad and NNN triad. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7411-7418, 2008
  • Kenji Takahashi, Toshifumi Sato, Yosuke Katsumura, Jinfeng Yang, Takafumi Kondoh, Yoichi Yoshida, Ryuzi Katoh
    RADIATION PHYSICS AND CHEMISTRY 77 10-12 1239 - 1243 2008年10月 [査読無し][通常論文]
     
    We examined formation of solvated electrons in several ionic liquids composed of ammonium, pyrrolidinium and piperidinium cations by observing absorption spectra in the visible and near-infrared regions using pulse radiolysi. We also examined reactions of the solvated electrons with imidazolium cations in the ionic liquids. The reaction rate constants were an order of magnitude faster than the diffusion-limited rate calculated from the viscosity. The electrons before full solvation (dry electrons) reacted efficiently with the imidazolium cations. These observations suggest that the electrons in the ionic liquids can move easily before solvation. The scavenging of the dry electron by the imidazolium cation was also examined using C2-alkylated-imidazolium cations. It is found that the alkylation of imidazolium suppresses the reactivity with the dry electron. (c) 2008 Elsevier Ltd. All rights reserved.
  • Issei Otsuka, Ryosuke Sakai, Ryohei Kakuchi, Toshifumi Satoh, Toyoji Kakuchi
    EUROPEAN POLYMER JOURNAL 44 9 2971 - 2979 2008年09月 [査読無し][通常論文]
     
    Polycarbohydrate macromonomers with different degrees of polymerization (DP), that is, end-functionalized (1 -> 6)-2.5-anhydro-3,4-di-O-ethyl-D-glucitols with 4-ethynylbenzoyl groups (macromonomer 2: DP = 6.6. and macromonomer 3: DP = 9.5) were synthesized. The copolymerizations of these nnacromonomers and phenylactylene (PA) were carried out in various molar ratios to give poly(phenylacetylene)s bearing a polycarbohydrate ionophore as the graft chain with various grafting rates, poly-(2(x)-co-PA(y)) and poly(3(x)-co-PA(y)). These polymers showed split-type circular dichroism (CD) spectra in the long absorption region of the conjugated polymer backbones (280-500 nm). This indicated that poly-(2(x)-co-PA(y)) and poly-(3(x)-co-PA(y)) had predominantly one-handed helical conformations in the backbones. The CD spectral patterns of these polymers were inverted in the presence of metal cationic guest Molecules. On the other hand, control experiments using poly(phenylacetylene)s bearing a monocarbohydrate (poly-(4(x)-co-PA(y))) and metal cations did not show such a CD spectral inversion. These results clearly indicated that the chiroptical switching of the poly(phenylacetylene)s bearing polycarbohydrate ionophore was attributable to the host-guest complexation of the polycarbohydrate ionophore with metal cations. (c) 2008 Elsevier Ltd. All rights reserved.
  • Microwave-Assisted Heating of Glucose in High-Boiling Solvent
    Akiyoshi Sasaki, Masahide Sasaki, Kenji Takahashi, Atsushi Narumi, Toshifumi Satoh, Toyoji Kakuchi, Harumi Kaga
    Proceedings of Grobal Congress on Microwave Energy Applications 669-670(2008)  Proceedings of Grobal Congress on Microwave Energy Applications 2008年08月 [査読無し][通常論文]
  • Depolymerization of Cellulose in High-Boiling Solvent by Microwave-Assisted Heating
    Akiyoshi Sasaki, Masahide Sasaki, Kenji Takahashi, Atsushi Narumi, Toshifumi Satoh, Toyoji Kakuchi, Harumi Kaga
    Proceedings of Grobal Congress on Microwave Energy Applications 607-608(2008)  Proceedings of Grobal Congress on Microwave Energy Applications 2008年08月 [査読無し][通常論文]
  • Toshifumi Satoh, Yuki Kinugawa, Masaki Tamaki, Yoshikazu Kitajyo, Ryosuke Sakai, Toyoji Kakuchi
    MACROMOLECULES 41 14 5265 - 5271 2008年07月 [査読無し][通常論文]
     
    A novel series of bio-based hyperbranched polymers, i.e., hyperbranched polyterpene alcohols, were prepared by the cationic ring-opening polymerizations of citronellol oxide (1) and nopol epoxide (2) using boron trifluoride diethyl etherate (BF3 center dot OEt2) as the catalyst. The polymerizations of 1 and 2 homogeneously proceeded without gelation to produce organic solvent-soluble polymers (poly-1 and poly-2, respectively). The absolute weight-average molecular weights (M-W,M-MALLS), which were measured by a multiangle laser light scattering instrument (MALLS), were 3700-6200 g mol(-1) for poly(-1) and 9000-20 000 g mol(-1) for poly-2, which were ca. 1.4-4.8 times greater than the relative molecular weights (M-W,M-SEC) measured by size exclusion chromatography (SEC). The intrinsic viscosities ([eta]) of these polymers were very low in the range of 8.5-10.1 mL g(-1) for poly-1 and 5.9-9.5 mL g(-1) for poly-2. The Mark-Houwink-Sakurada exponent alpha was calculated to be 0.32-0.40 for poly-1 and 0.25-0.35 for poly-2. These results of the MALLS, SEC, and viscosity measurements suggested that these polymers exist in a compact spherical conformation in solution.
  • Atsushi Narumi, Keita Fuchise, Ryohei Kakuchi, Atsushi Toda, Toshifumi Satoh, Seigou Kawaguchi, Kenji Sugiyama, Akira Hirao, Toyoji Kakuchi
    MACROMOLECULAR RAPID COMMUNICATIONS 29 12-13 1126 - 1133 2008年07月 [査読無し][通常論文]
     
    The 2-chloropropionamide derivative featuring an azido group is used as the initiator for the ATRP of N-isopropylacrylamide (NIPAM) with copper(I) chloride (CuCl) and tris[2-(dimethylamino)ethyl]amine (Me(6)TREN) to produce the PNIPAM end-functionalized with an azido group. Subsequently, the 'click' reaction between the azido end-group and acetylene derivatives is demonstrated to produce PNIPAM in which the end-groups are modified by the phenyl, 4-phenoxyphenyl, butyl, octyl, carboxylic acid, and hydroxymethyl groups. The resulting PNIPAM derivatives show a LCST that ranges from 34.8 to 44.6 degrees C depending on the introduced end-group.
  • Masahide Sasaki, Kenji Takahashi, Yul Haneda, Hiroe Satoh, Akiyoshi Sasaki, Atsushi Narumi, Toshifumi Satoh, Toyoji Kakuchi, Harumi Kaga
    CARBOHYDRATE RESEARCH 343 5 848 - 854 2008年04月 [査読無し][通常論文]
     
    An aqueous solution of glucose was reacted at temperatures from 200 to 400 degrees C under atmospheric pressure using a continuous flow reactor. For reaction temperatures above 300 degrees C, the liquid product yield was not sensitive to the temperature change; on the other hand, below 300 degrees C it decreased rapidly with decreasing temperature. 1,6-Anhydro-beta-D-glucopyranose (AGP) and 1,6-anhydro-beta-D-glucofuranose (AGF) were the major components in the liquid product. The yields of AGP and AGF were 40% and 19%. respectively, at 360 degrees C and a feed rate of 0.5 mL/min. The optimum space time to produce AGP and AGF was about 0.2-0.4 s under the present temperature conditions. (C) 2008 Elsevier Ltd. All rights reserved.
  • Osamu Nishizawa, Hideki Misaka, Toyoji Kakuchi, Toshifumi Satoh
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 46 4 1185 - 1191 2008年02月 [査読無し][通常論文]
     
    Norbornene polymerization using the commercially available and inexpensive catalyst system, cyclopentadienylzirconium trichloride (CpZrCl3) and isobutyl-modified methylaluminoxane (MMAO), were carried out over a wide range of polymerization temperatures and monomer concentrations. For the CpZrCl3 catalyst system activated by aluminoxane with a 40 mol % methyl group and a 60 mol % isobutyl group (MMAO(40/60)), the polymerization temperature and monomer concentration significantly affected the molecular weight (M-n) of the obtained polymer and the catalytic activity. With an increase in the polymerization temperature from 0 to 27 degrees C, the catalytic activity and M. increased, but these values dramatically decreased with the increasing polymerization temperature from 27 to 70 degrees C, meaning that the most suitable temperature was 27 degrees C. The CpZrCl3/MMAO(40/60) ([Al]/[Zr] = 1000) catalyst system with the [NB] of 2.76 mol L-1 at 27 degrees C showed the highest activity of 145 kg mol(Zr)(-1) h(-1) and molecular weight of 211,000 g mol(-1). The polymerization using the CpZrCl3/MMAO(40/60) catalyst system proceeds through the vinyl addition mechanism to produce atactic polynorbornene, which was soluble in chloroform, toluene, and 1,2-dichlorobenzene, but insoluble in methanol. (C) 2008 Wiley Periodicals, Inc.
  • Polymerization of norbornene with half-zirconocene/modified methylaluminoxane catalyst system
    Polym. Prepr. 49 1 559  2008年 [査読無し][通常論文]
  • Synthesis and characterization of poly(P-phenylene ethynylene) bearing maltohexaose
    Polym. Prepr. 49 1 607 - 608 2008年 [査読無し][通常論文]
  • Ryohei Kakuchi, Sachiko Nagata, Ryosuke Sakai, Issei Otsuka, Hiroshi Nakade, Toshifumi Satoh, Toyoji Kakuchi
    CHEMISTRY-A EUROPEAN JOURNAL 14 33 10259 - 10266 2008年 [査読無し][通常論文]
     
    A colorimetric detection susceptible to the dimensions of guest counteranions has been demonstrated by using poly(phenylacetylene) with L-leucine and urea functionalities (poly-PA-Leu). Poly-PA-Leu was prepared from N-(4-ethynylphenylcarbomoyl)-L-leucine ethyl ester (PA-Leu) by using [Rh(+){eta(6)-C(6)H(5))B(-)(C(6)H(5))(3)} (2,5-norbornadiene)] as a catalyst. The biased helical conformation of poly-PA-Leu was demonstrated through Cotton effects in the circular dichroism (CD) spectra. The addition of ammonium salts, including tetra-n-butylammonium acetate, tetra-n-butylammonium chloride, and tetra-n-butylammonium bromide anions (CH(3)COO(-), Cl(-), and Br(-)), into the poly-PA-Leu solution intensified the CD responses of poly-PA-Leu, which is indicative of the chiral adjustability of anion recognition by using urea groups. In addition, the combination of poly-PA-Leu with the CH(3)COO(-), Cl(-), and Br(-) anions promoted large redshifts in the absorption spectra, thus providing dramatic color changes from pale yellow to red. Guest dependency in the CD and UV/Vis spectra was clearly correlated with the size of the counteranions. Fundamentally, the addition of tetra-n-butylammonium nitrate, tetra-n-butylarmmonium hydrogen sulfate, tetra-n-butylammonium perchlorate, tetra-n-butylammonium fluoride, and tetra-n-butylammonium iodide anions (NO(3)(-), HSO(4)(-), ClO(4)(-), N(3)(-), F(-), and I(-)) has no effect on either the CD or UV/Vis spectra clearly demonstrated the guest-dimension selectivity of poly-PA-Leu in counteranion recognition.
  • Yoshikazu Kitajyo, Yuki Kinugawa, Masaki Tamaki, Harumi Kaga, Noriaki Kaneko, Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULES 40 26 9313 - 9321 2007年12月 [査読無し][通常論文]
     
    The cationic ring-opening polymerizations of an alicyclic epoxyalcohol, 3,4-epoxycyclohexanemethanol (1), were carried Out using boron trifluoride diethyletherate (BF3 center dot OEt2) as a catalyst. Polymerization of I heterogeneously proceeded to yield a gel-free polymer (poly-1). On the basis of the C-13 NMR measurement, poly-1 was a hyperbranched polymer with numerous terminal units, and the degrees of branching (DBs) of poly-1 were in the range from 0.36 to 0.42. The three-dimensional property of poly-1 was investigated by comparison to the physical property of a linear poly(3,4-epoxycyclohexanemethanol) (poly-3). The viscosity and Mark - Houwink exponent a of poly-1 were much lower than those of poly-3, suggesting that poly-1 had a compact conformation in solution. In addition, the glass-transition temperature (T-g) of poly-1 was ca. 105 degrees C, which was also lower than that of poly-3. A novel amphiphilic dendritic polymer (poly-1ASP) having a hydrophobic poly-1 core and hydrophilic L-aspartic acid shell was synthesized. On the basis of the results of an encapsulation experiment, poly-1ASP possessed an encapsulation property for hydrophobic molecule (Reichardt's dye) in water.
  • Atsushi Narumi, Ryosuke Sakai, So Ishido, Masako Sone, Toshifumi Satoh, Harumi Kaga, Hiroshi Nakade, Toyoji Kakuchi
    MACROMOLECULES 40 26 9272 - 9278 2007年12月 [査読無し][通常論文]
     
    We report a series of cyclopolymerizations of bis(4-vinylbenzoate) monomers through an atom transfer radical polymerization (ATRP) using chiral ligands. Cyclized polymers showing chiroptical properties were produced by polymerization of the racemic bifunctional monomer, rac-2,4-pentanediyl bis(4-vinylbenzoate) (rac-1), and enantiomerically unbalanced bifunctional monomers were recovered, providing substantial evidence for the enantiomer-selective polymerization of rac-I mediated through the ATRP with chiral ligands. A comparison between the enantiomerically pure monomers, (2R,4R)-2,4-pentanediyl bis(4-vinylbenzoate) (RR-1) and (2S,4S)2.4-pentanediyl bis(4-vinylbenzoate) (SS-1), revealed a drastic discrepancy in the rates Of their homopolymerizations during the ATRP. The enantiomeric copolymerization of RR-1 and SS-1 indicated that the monomer reactivity ratio of RR-1 was higher than that of SS-1 for the ATRP with chiral ligands. The results of both homopolymerizations and copolymerizations clearly demonstrate the propensity for incorporation of the RR-1 enantiomer and thus the enantiomer-selective polymerization in this system. The monomer-structural effects on the enantiomer-selectivity were examined, and it was concluded that the chirality in the monomer is also essential for the enantiomer-selective polymerization as well as the chiral ligands for ATRP. Finally, the viability of the cyclopolymerization in the enantiomer-selective polymerization was proved using mono(4-vinylbenzoate) monomers incapable of cyclizing through the polymerization.
  • Issei Otsuka, Takayoshi Hongo, Hiroshi Nakade, Atsushi Narumi, Ryosuke Sakai, Toshifumi Satoh, Harumi Kaga, Toyoji Kakuchi
    MACROMOLECULES 40 25 8930 - 8937 2007年12月 [査読無し][通常論文]
     
    We report the chiroptical properties and lectin affinities of poly(phenylacetylene)s featuring saccharide functionalities including D-glucopyranoside and D-galactopyranoside. The glycoconjugated poly(phenylacetylene)s were synthesized by rhodium mediated polymerization from phenylacetylene monomers containing a series of saccharide groups; 4-ethynylphenyl 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranoside (PA-(alpha-Glc-OAc), beta-D-glucopyranoside (PA-beta-Glc-OAc), alpha-D-galactopyranoside (PA-alpha-Gal-OAc), and beta-D-galactopyranoside (PA-beta-Gal-OAc). On the basis of CD and UV-vis experiments, these polymers were found to have biased helical conformations in a variety of solvents, such as CHCl3, THF, and HFIP. The deprotection of the acetyl groups using CH3ONa provided the linear saccharide arrays with diverse saccharide functionalities; poly-PA-alpha-Glc, poly-PA-beta-Glc, poly-PA-alpha-Gal, and poly-PA-beta-Gal. CD experiments revealed that poly-PA-alpha-Glc and poly-PA-,beta-Glc have identical helical structures, and poly-PA-alpha-Gal and poly-PA-beta-Gal feature mirror-imaged helical structures. The binding affinities to lectins were demonstrated by a fluorometric assay using the fluorescein isothiocyanate labeled lectins, such as Concanavalin A (FITC-Con A) and peanut agglutinin (FITC-PNA). As expected, increasingly enhanced affinities for Con A and PNA were observed for the helical saccharide arrays in comparison to the monomeric models. Accordingly, the enhanced affinities are essentially correlated with the multivalency and conformational organization of the saccharide functionalities in the arrays.
  • Ryohei Kakuchi, Sachiko Nagata, Ryosuke Sakai, Takafumi Yonekawa, Issei Otsuka, Toshifumi Satoh, Toyoji Kakuchi
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 234 2007年08月 [査読有り][通常論文]
  • Takayoshi Hongo, Issei Otsuka, Atsushi Narumi, Ryosuke Sakai, Toshifumi Satoh, Harumi Kaga, Toyoji Kakuchi
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 234 2007年08月 [査読有り][通常論文]
  • Issei Otsuka, Takayoshi Hongo, Atsushi Narumi, Ryosuke Sakai, Toshifumi Satoh, Harumi Kaga, Toyoji Kakuchi
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 234 2007年08月 [査読有り][通常論文]
  • Ryohei Kakuchi, Atsushi Toda, Atsushi Narumi, Ryosuke Sakai, Toshifumi Satoh, Kenji Sugiyama, Christopher W. Macosko, Akira Hirao, Toyoji Kakuchi
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 234 2007年08月 [査読有り][通常論文]
  • Toshifumi Satoh, Toyoji Kakuchi
    MACROMOLECULAR BIOSCIENCE 7 8 999 - 1009 2007年08月 [査読有り][通常論文]
     
    The synthesis of novel hyperbranched carbohydrate polymers, prepared by the ring-opening multibranching polymerizations of anhydro and dianhydro sugars, is described. The hyperbranched carbohydrate polymers were formed by the cationic polymerization of 1,6-anhydro-beta-D-hexopyranose, 1,4-anhydrotetritol, 2,3-anhydrotetritol, and 1,2:5,6-dianhydro-D-mannitol. These polymerizations proceeded without gelation to produce water-soluble hyperbranched carbohydrate polymers with controlled molecular weights and narrow polydispersities. The values for the degree of branching of the polymers were in the range of 0.28-0.50. The polymerization method, which proceeds through a ring-opening reaction by a proton-transfer reaction mechanism, is a facile method leading to a spherical carbohydrate polymer with a high degree of branching.
  • Formation of Anhydroglucose from Polysaccharide in Ionic Liquids
    Momoko Hayashi, Miho Hamauchi, Hiroe Satoh, Kenji Takahashi, Toshifumi Satoh, Toyoji Kakuchi, Harumi Kaga
    Proceedings of 2nd International Congress on Ionic Liquid 219  Proceedings of 2nd International Congress on Ionic Liquid 2007年07月 [査読無し][通常論文]
  • Yoshikazu Kitajyo, Yumiko Nawa, Masaki Tamaki, Hirofumi Tani, Kenji Takahashi, Harumi Kaga, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER 48 16 4683 - 4690 2007年07月 [査読無し][通常論文]
     
    Hyperbranched polythreitol (1) with different molecular weights (M-w,M-SLS: 1.18 x 10(4) and 4.79 x 10(4)) was reacted with trityl chloride in DMF to afford a novel amphiphilic polymer (2) consisting of 1 as the hydrophilic core and the trityl groups as the hydrophobic shell. Compound 2 was tested for its ability to act as a unimolecular nanocapsule toward the water-soluble dye, rose bengal (RB). Their encapsulation and release properties were also evaluated by comparison with the degree of substitution (DS) of the trityl groups, i.e., the hydrophobic shell density. The polymers were found to have very good unimolecular nanocapsule characteristics even at extremely low concentrations. The average number of RBs per polymer molecule depended on the hydrophilic core size and the hydrophobic shell density. The increasing DS value led to a decrease in the encapsulated amount due to the decrease in the hydrophilic core space, while the low DS value (less than ca. 20 rnol%) led to a destabilization as a unimolecular nanocapsule and a lower encapsulation ability. In particular, 2 with ca. 23% DS value showed an efficient encapsulation. Based on a release test of the RB-loaded unimolecular nanocapsules, the polymers showed a high RB-holding ability in water. (c) 2007 Elsevier Ltd. All rights reserved.
  • Yoshikazu Kitajyo, Tomoko Imai, Yoko Sakai, Masaki Tamaki, Hirofumi Tani, Kenji Takahashi, Atsushi Narumi, Harumi Kaga, Noriaki Kaneko, Toshifumi Satoh, Toyoji Kakuchi
    POLYMER 48 5 1237 - 1244 2007年02月 [査読無し][通常論文]
     
    The synthesis of a novel unimolecular reverse micelle, the hyperbranched D-glucan carbamate (3), was accomplished through the carbamation reaction of the hyperbranched D-glucan (1) with the N-carbonyl L-leucine ethyl ester (2) in pyridine at 100 degrees C. Polymer 3 was soluble in a large variety of organic solvents, such as methanol, acetone, chloroform, and ethyl acetate, and insoluble in water, which remarkably differed from the solubility of 1. The degree of carbamate substitution (DS) for 3 was controlled by the feed rate of 2, and the DS values were in the range of 46.0-93.7%. Polymer 3 possessed the encapsulation ability for water-soluble molecules, such as rose bengal, thymol blue, and alizarin yellow in chloroform, and the encapsulation ability depended on the hydrophilicity of 3 and the molecular size of the dye. The rose bengal (RB) encapsulated polymer (RB/3) showed a slow release from the RB/3 system into water at neutral pH, while the release rate was significantly accelerated by the hydrolysis of the hydrophobic polymer shell under basic conditions. (c) 2007 Elsevier Ltd. All rights reserved.
  • Synthesis and Thermoresponsive Property of Poly(N-Isopropylacrylamide) with Aryl Chain-End and Its Cyclodextrin-Inclusion Complex
    Polymer Preprints 48 2 350 - 351 2007年 [査読無し][通常論文]
  • Synthesis and Chiroptical Property of Poly(Phenylacetylene) Bearing Maltohexaose
    Polymer Preprints 48 2 119 - 120 2007年 [査読無し][通常論文]
  • Synthesis and Anion Sensing Property of Poly(Phenylacetylene) Bearing Urea Derivative of L-Leucine as Pendant
    Polymer Preprints 48 2 115 - 116 2007年 [査読無し][通常論文]
  • Anomer-Selective Synthesis of Poly(Ρ-Ethynylphenyl Hexopyranoside)s: Effects of Anomeric Configuration on Their Stimulus Response and Lectin Detection
    Polymer Preprints 48 2 82 - 83 2007年 [査読無し][通常論文]
  • Precise Tuning of Thermoresponsive Property of Poly(N-Isopropylacrylamide)S by Combination of ATRP and "Click" Chemistry
    Polymer Preprints 48 2 344 - 345 2007年 [査読無し][通常論文]
  • Synthesis and Characterization of Hyperbranched Polymer by Cationic Ring-Opening Polymerization of 3,4-Epoxycyclohexanemethanol
    Polymer Preprints 48 2 328 - 329 2007年 [査読無し][通常論文]
  • Atsushi Narumi, Yutaka Miura, Issei Otsuka, Shin Yamane, Yoshikazu Kitajyo, Toshifumi Satoh, Akira Hirao, Noriaki Kaneko, Harumi Kaga, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 44 16 4864 - 4879 2006年08月 [査読無し][通常論文]
     
    This article describes that glucose, maltose, maltotriose, maltotetraose, maltopentaose, and maltohexaose (a, b, c, d, e, and f, respectively) were introduced into the initiating chain-end of polystyrene (PSt) through the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated radical polymerization. A series of glycoconjuaged. TEMPO-adducts, 1a-f, was synthesized and used as the initiators for the polymerization of styrene (St) for 6 h at 120 degrees C to afford the end-functionalized PSt's with the acetyl saccharides, 2a-f, in the yields of 37-43%. For 2a-f obtained by the polymerizations using the [St]/[1] of 125, 250, and 500, the number-average molecular weights determined by size exclusion chromatography (SEC), M-n,M-SEC's, were 4800-6300, 8800-10,600, and 18,40025,200, respectively, which fairly agreed with the predicted values. The end-functionalized PSt's with saccharides, 3a-f, which were obtained from the deacetylation of 2a-f using sodium metboxide in dry THF, formed the polymeric reverse micelles consisting of a saccharide-core and a PSt-shell in chloroform and toluene. The static laser light scattering (SLS) measurements provided the average molar mass of the aggregates in toluene, M-w,M-SLS's, which ranged from 7.50 x 10(4) to 1.77 x 10(5) for 3a, from 1.90 x 10(5) to 4.93 x 10(5) for 3b, from 4.41 x 10(5) to 7.21 x 10(5) for 3c, from 5.85 x 10(5) to 8.51 x 10(5) for 3d, from 7.55 x 10(5) to 8.53 x 10(5) for 3e, and from 8.54 x 10(5) to 9.26 x 10(5) for 3f The aggregation numbers, N-agg's, which were calculated from the M-w,(SLS)'s, were from 7 to 24 for 3a, from 20 to 37 for 3b, from 34 to 89 for 3c, from 39 to 116 for 3d, from 41 to 145 for 3e and from 31 to 146 for 3f It was confirmed that the aggregation property, such as the M-w,M-SLS or N-agg values, was strongly related to the polymerization degrees of St (DP's) or the number of the glucose residues (n's) for 3a-f. (c) 2006 Wiley Periodicals, Inc.
  • Atsushi Narumi, Issei Otsuka, Takeshi Matsuda, Yutaka Miura, Toshifumi Satoh, Noriaki Kaneko, Harumi Kaga, Toyoji Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 44 13 3978 - 3985 2006年07月 [査読無し][通常論文]
     
    Styrene (St) was polymerized with alpha,alpha'-bis(2',2',6,6'-tetramethyl-1'-piperidinyloxy)-1,4-diethylbenzene (1) as an initiator (bulk, [St]/[1] = 570) at 120 degrees C for 5.0 h to obtain polystyrene having 2,2,6,6-tetramethylpiperidiloxy moieties on both sides of the chain ends (2) with a number-average molecular weight (M-n) of 14,300 and a polydispersity index [weight-average molecular weight/number-average molecular weight (M-w/M-n)] of 1.14. 4-Vinylbenzyl glucoside peracetate (3a) was polymerized with 2 as a macromolecular initiator and dicumyl peroxide (DCP) as an accelerator in chlorobenzene at 120 degrees C. The polymerization with the [3a]/[2]/[DCP] ratio of 30/1/1.2 for 5 h afforded a product in a yield of 73%; it was followed by purification with preparative size exclusion chromatography to provide the ABA triblock copolymer containing the pendant acetyl glucose on both sides of the chain ends (4a; M-n = 21,000, M-w/ M-n = 1.16). Similarly, the polymerization of 4-vinylbenzyl maltobexaoside peracetate produced the ABA triblock copolymer containing the pendant acetyl maltohexaose on both side of the chain end (4b; M-n = 31,800, M-w/M-n = 1.11). Polymers 4a and 4b were modified by deacetylation into amphiphilic ABA triblock copolymers containing the pendant glucose and maltohexaose as hydrophilic segment, 5a and 5b, respectively. (c) 2006 Wiley Periodicals, Inc.
  • R Sakai, Otsuka, I, T Satoh, R Kakuchi, H Kaga, T Kakuchi
    MACROMOLECULES 39 12 4032 - 4037 2006年06月 [査読無し][通常論文]
     
    Cis-transoidal poly(4'-ethynylbenzo-15-crown-5) ( 2) prepared by the polymerization of 4'-ethynylbenzo- 15-crown-5 with Rh(nbd) BPh4 has been used as a thermoresponsive material with a chiral on-off switching property. In the circular dichroism ( CD) spectrum of 2 in the presence of the perchloric acid salt of L-phenylglycine (L-Pgly center dot HClO4) at - 30 degrees C, a large Cotton effect with an intensity of + 2.96 x 10(4) deg cm(2) dmol(-1) was observed in the range from 300 to 550 nm corresponding to the absorption of the conjugated polymer backbone, indicating that 2 formed the one-handed helical structure triggered by the host-guest complexation with L-Pgly center dot HClO4. However, the induced CD (ICD) intensity significantly decreased with the increasing temperature and almost completely disappeared at 30 degrees C or over. Furthermore, an alternate temperature modulation between - 30 and 30 degrees C brought about the reversible on-off switching of the ICD of 2.
  • Atsushi Narumi, Harumi Kaga, Yutaka Miura, Issei Otsuka, Toshifumi Satoh, Noriaki Kaneko, Toyoji Kakuchi
    BIOMACROMOLECULES 7 5 1496 - 1501 2006年05月 [査読無し][通常論文]
     
    4-Vinylbenzyl maltohexaoside peracetate (1) was copolymerized with divinylbenzene (DVB) using 1-phenyl-1( (2', 2', 6', 6'-tetramethyl-1'-piperidinyloxy) ethane (2) in m-xylene. The copolymerizations were performed at 138 degrees C for 20 h using the mole fraction of 1 in the total feed of 1 and DVB (F-1: [1]/[1]+[DVB]) varying from 0.11 to 0.38, affording polymeric products in yields ranging from 32 to 40%. The characterizations by linear PS-calibrated size exclusion chromatography (SEC), dynamic laser light scattering (DLS) measurements, and H-1 NMR spectroscopy indicated that the product was assignable to the cross-linked poly(4-vinylbenzyl maltohexaoside peracetate) particle which is able to produce stable solutions, i.e., the PSt microgel with acetyl maltohexaose, 3. The specific rotations ([alpha](D)(23), c) 1.0 CHCl3) of 3 ranged from +43.3 degrees to +85.6 degrees. The average molar masses determined by the static laser light scattering (SLS) measurement of 3, M-w,M- SLS's, were from 64 700 to 118 000, which were calculated using the respective refractive index increments, dn/dc's, ranging from 0.03387 to 0.08340 The apparent numbers of the 1, 2, and DVB units in 3, N-1, N-2, and N-DVB, which were estimated from the respective [ R] D 23 values, Mw, SLS's, and real yields, ranged from 22 to 35, from 7 to 26, and from 146 to 506, respectively. The deacetylation of 3 was achieved by treatment with sodium methoxide in dry 1,4-dioxane to produce the PSt microgel with maltohexaose as the hydrophilic segment, 4, as a white solid. The solubility of 4 in various solvents was examined, indicating that a hydrophilic property was effectively introduced. Notably, 4 gave clear solutions in the mixed solvent of 1,4-dioxane and H2O. The ability to solubilize fullerite (mixture of fullerenes, C-60/C-70) ca. 9/1) in aqueous solutions was examined according to the literature method. Approximately, 100 mg of 4 (1.7 mu mol) solubilizes 1.3 mg of fullerite (1.7 mu mol).
  • Atsushi Narumi, Qian Duan, Yutaka Miura, Toshifumi Satoh, Harumi Kaga, Toyoji Kakuchi
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 231 1 317 - 318 2006年03月 [査読無し][通常論文]
  • A Narumi, H Kaga, Y Miura, T Satoh, N Kaneko, T Kakuchi
    POLYMER 47 7 2269 - 2273 2006年03月 [査読無し][通常論文]
     
    4-Vinylbenzyl glucoside peracetate (1) was copolymerized with divinylbenzene (DVB) using I-phenyl-1-(2',2',6',6'-tetramethyl-1'-piperidinyloxy)ethane (2) as an initiator in in-xylene at 138 degrees C for 20h ([DVB]/[2]=28; [DVB]=0.62mol L-1). The copolymerizations were performed using the mole fraction of I in the total feed of I and DVB (F-1: [1]/[1] + [DVB]) ranging from 0.11 to 0.38 that produced the polystyrene (PSt) microgel with acetyl glucose, 3, in 46-53% yields. Dynamic laser light scattering (DLS) measurements showed that 3 was stably suspended in toluene as particles with average diameters (d's) ranging from 12 to 22 nm. A static laser light scattering (SLS) measurement gave the average molar mass, M-w,M-SLS, of 3 that ranged from 9.69 X 10(4) to 6.96 X 10(5). The numbers of the 1, 2, and DVB units in 3 (N-1, N-2, and N-DVB, respectively) were from I I I to 238, from 17 to 208, and from 350 to 45 10, respectively. The deacetylation of 3 was achieved by treatment with sodium methoxide in dry 1,4-dioxane to produce the PSt microgel with glucose as the hydrophilic segment, 4. The solubilities of 4 in toluene, CHCl3, THF, 1,4-dioxane, pyridine, DMF, DMSO, and H2O, and the mixture of H2O and 1,4-dioxane were examined, indicating that a hydrophilic property had been effectively introduced into 4. (c) 2006 Elsevier Ltd. All rights reserved.
  • XD Shen, Y Kitajyo, Q Duan, A Narumi, H Kaga, N Kaneko, T Satoh, T Kakuchi
    POLYMER BULLETIN 56 2-3 137 - 143 2006年02月 [査読有り][通常論文]
     
    The reaction of the carboxymethyl cellulose sodium salt (Na-CMC) (degrees of substitution (DS) = 1.2) with N-hydroxysuccinimide (Su-OH) in the presence of 1-hydroxybenzotriazole and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) was carried out in water to obtain the Su-OH ester of carboxymethyl cellulose, Su-CMC, with the DS values of 0.19 - 1.04. N-Allylcarbamoylmethyl cellulose (Allyl-CMC), which was prepared from the reaction of Su-CMC with an excess amount of allylamine, was crosslinked by UV-irradiation. In addition, the photocrosslinked Allyl-CMC film was swollen with water to form a hydrogel having a relatively high water-swelling property, e.g., the degree of swelling (ds) was ca. 360% for Allyl-CMC with the DS of 0.93.
  • Y Miura, T Satoh, A Narumi, O Nishizawa, Y Okamoto, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 44 4 1436 - 1446 2006年02月 [査読無し][通常論文]
     
    The copper-mediated atom transfer radical polymerization of methyl methacrylate (MMA) in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) was studied to simultaneously control the molecular weight and tacticity. The polymerization using tris[2-(dimethylamino)ethyl]amine (Me6TREN) as a ligand was performed even at -78 degrees C with a number-average molecular weight (M-n) of 13,400 and a polydispersity (weight-average molecular weight/number-average molecular weight) of 1.31, although the measured M.'s were much higher than the theoretical ones. The addition of copper(II) bromide (CuBr2) apparently affected the early stage of the polymerization; that is, the polymerization could proceed in a controlled manner under the condition of [MMA](0)/[methyl alpha-bromoisobutyrate](0)/[CuBr](0)/[CuBr2](0)/[Me6TREN](0) = 200/1/1/0.2/1.2 at -20 degrees C with an MMA/HFIP ratio of 1/4 (v/v). For the field desorption mass spectrum of (CuBr)-Br-I/Me6TREN in HFIP, there were [Cu(Me6TREN)Br](+) and [Cu(Me6TREN)OCH(CF3)(2)](+), indicating that HFIP should coordinate to the Cu-I/Me6TREN complex. The syndiotacticity of the obtained poly(methyl methacrylate)s increased with the decreasing polymerization temperature; the racemo content was 84% for -78 degrees C, 77% for -30 degrees C, 75% for -20 degrees C, and 63% for 30 degrees C. (c) 2006 Wiley Periodicals, Inc.
  • Q Duan, Y Miura, A Narumi, Shen, X, S Sato, T Satoh, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 44 3 1117 - 1124 2006年02月 [査読無し][通常論文]
     
    N-Isopropylacrylamide (NIPAM) was polymerized using 1-pyrenyl 2-chloropropionate (PyCP) as the initiator and CuCl/tris[2-(dimethylamino)ethyl]-amine (Me6TREN) as the catalyst system. The polymerizations were performed using the feed ratio of [NIPAM](0)/[PyCP](0)/[CuCl](0)/[Me6TREN](0) = 50/1/1/1 in DMF/water of 13/2 at 20 degrees C to afford an end-functionalized poly(N-isopropylacrylamide) with the pyrenyl group (Py-PNIPAM). The characterization of the Py-PNIPAM using matrix-assisted laser desorption ionization time-of-flight mass spectrometry provided the number-average molecular weight (M-n,M-MS). The lower critical solution temperature (LCST) for the liquid-solid phase transition was 21.7, 24.8, 26.5, and 29.3 degrees C for the Py-PNIPAMs with the M(n,MS')s of 3000, 3400, 4200, and 5000, respectively; hence, the LCST was dramatically lowered with the decreasing M-n,M-MS. The aqueous Py-PNIPAM solution below the LCST was characterized using a static laser light scattering (SLS) measurement to determine its molar mass, M,,,SLS. The aqueous solutions of the Py-PNIPAMs with the M-n,M-MS's of 3000, 3400, 4200, and 5000 showed the M-w,M-SLS of 586,000, 386,000, 223,000, and 170,000, respectively. Thus, lowering the LCST for Py-PNIPAM should be attributable to the formation of the PNIPAM aggregates. The LCST of 21.7 degrees C for Py-PNIPAM with the Mn,MS of 3000 was effectively raised by adding beta-cyclodextrin (beta-CD) and reached the constant value of similar to 26 degrees C above the molar ratio of [beta-CD]/[Py-PNIPAM] = 2/1, suggesting that beta-CD formed an inclusion complex with pyrene in the chain-end to disturb the formation of PNIPAM aggregates, thus raising the LCST. (c) 2005 Wiley Periodicals, Inc.
  • より安全で高性能な医用材料を目指して
    創成ニューズレター (北海道大学) 4 10 - 11 2006年 [査読無し][通常論文]
  • Shen Xiande, Kitajyo Yoshikazu, Duan Qian, Narumi Atsushi, Kaga Harumi, Kaneko Noriaki, Satoh Toshifumi, Kakuchi Toyoji
    Polym. Bull. 56 2-3 137 - 143 Springer Berlin / Heidelberg 2006年 [査読無し][通常論文]
     
    The reaction of the carboxymethyl cellulose sodium salt (Na-CMC) (degrees of substitution (DS) = 1.2) with N-hydroxysuccinimide (Su-OH) in the presence of 1-hydroxybenzotriazole and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) was carried out in water to obtain the Su-OH ester of carboxymethyl cellulose, Su-CMC, with the DS values of 0.19 – 1.04. N-Allylcarbamoylmethyl cellulose (Allyl-CMC), which was prepared from the reaction of Su-CMC with an excess amount of allylamine, was crosslinked by UV-irradiation. In addition, the photocrosslinked Allyl-CMC film was swollen with water to f...
  • T Satoh, M Tamaki, Y Kitajyo, T Maeda, H Ishihara, T Imai, H Kaga, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 44 1 406 - 413 2006年01月 [査読無し][通常論文]
     
    A novel biodegradable unimolecular reversed micelle consisting of a poly (L-lactide) (PLA) shell and a hyperbranched D-mannan (HBM) core, that is, a chestnut-shaped polymer (PLA-HBM), was synthesized by the polymerization Of L-lactide on HBM with 4-(dimethylamino)pyridine (DMAP) as the catalyst. The obtained polymers were soluble in dimethyl sulfoxide, tetrahydrofuran, and chloroform but insoluble in H2O. The molecular weights of the PLA chain on PIA-HBM tended to increase with increasing polymerization time. The number of PLA chains on PLA-HBM could be controlled by the ratio of DMAP to the sugar unit in HBM. The obtained copolymer, PLAHBM, acted as a unimolecular reversed micelle with an encapsulation ability toward the hydrophilic molecule. In addition, the entrapped hydrophilic molecules were slowly released from the core of PLA-HBM, and the release rate was accelerated by the breaking of the PLA chains of the shell when proteinase K as a hydrolase of PLA was used. (c) 2005 Wiley Periodicals, Inc.
  • R Sakai, Otsuka, I, T Satoh, R Kakuchi, H Kaga, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 44 1 325 - 334 2006年01月 [査読無し][通常論文]
     
    The asymmetric polymerization of 4'-isocyanatobenzo-18-crown-6 with the lithium amide of (S)-(2-methoxymethyl)pyrrolidine successfully proceeded to afford end-functionalized poly(4'-isocyanatobenzo-18-crown-6) with (S)-(2-methoxymethyl)pyrrolidine (polymer 2). In the circular dichroism (CD) spectrum of 2, a clear positive Cotton effect was observed in the range of 240-350 run corresponding to the absorption of the polymer backbone, indicating that 2 partially formed a one-handed helical structure, which was preserved by the chirality of (S)-(2-methoxymethyl)pyrrolidine bonding to the terminal end in 2. In the titration experiments for the CD intensity of 2 in the presence Of D- and L-Phe-HClO4 (where Phe is phenylalanine), a small but remarkable difference was observed in the amount of the chiral guest needed for saturation of the CD intensity and in the saturated CD intensity, indicating that the extremely stable, one-handed helical part should exist in the main chain of 2, which was not inverted even when the unfavorable chiral guest for the predominant helical sense, L-Phe.HClO4, was added. In addition, helical polymer 2 exhibited a chiral discrimination ability toward racemic guests; that is, the guests were extracted from the aqueous phase into the organic phase with enantiomeric excess. The driving force of the chiral discrimination ability of 2 should certainly be attributed to the one-handed helical structure in 2. (c) 2005 Wiley Periodicals, Inc.
  • SATOH Toshifumi, OTSUKA Issei, SAKAI Ryosuke, SAITOH Kei, UMEDA Satoshi, TSUDA Katsuyuki, HASHIMOTO Hisaho, KAKUCHI Toyoji
    Polymer journal 38 5 490 - 494 Society of Polymer Science, Japan 2006年 [査読無し][通常論文]
  • Q Duan, A Narumi, Y Miura, XD Shen, SI Sato, T Satoh, T Kakuchi
    POLYMER JOURNAL 38 3 306 - 310 2006年 [査読無し][通常論文]
  • Otsuka, I, R Sakai, T Satoh, R Kakuchi, H Kaga, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 43 23 5855 - 5863 2005年12月 [査読無し][通常論文]
     
    A poly(phenylacetylene) bearing a polycarbohydrate ionophore as a graft chain (copolymer 4) was synthesized by the copolymerization of end-functionalized (1 -> 6)-2,5-anhydro-3,4-di-O-ethyl-D-glucitol with a 4-ethynylbenzoyl group (macromonomer 2) with phenylacetylene. Copolymer 4 showed a split-type circular dichroism (CD) in the long absorption region of the conjugated polymer backbone (280-500 nm), and the CD pattern varied in response to external stimuli, such as the solvents and temperature. This suggested that 4 had a predominantly one-handed helical conformation in the polyacetylene backbone. The CD pattern of 4 was completely inverted by the formation of a complex between the macromolecular ionophore units and the selected metal cations, that is, Ba2+, Pb2+, Sr2+, Na+, and Li+. This suggested that copolymer 4 underwent a helix-helix transition through the host-guest complexation with achiral inorganic metal cations. (c) 2005 Wiley Periodicals, Inc.
  • T Satoh, T Imai, S Umeda, K Tsuda, H Hashimoto, T Kakuchi
    CARBOHYDRATE RESEARCH 340 17 2677 - 2681 2005年12月 [査読無し][通常論文]
     
    The (salen)(CoOAc)-O-III ((R,R)-1 and (S,S)-1) catalyzed cyclizations of the chiral dianhydro sugars, 1,2:5,6-dianhydro-3,4-di-O-methyl-D-glucitol (2), 1,2:5,6-dianhydro-3,4-di-O-methyl-D-mannitol (3), 1,2:5,6-dianhydro-3,4-di-O-methyl-L-iditol (4), and 1,2:4,5-dianhydro-3-O-methyl-L-arabinitol (5), is a facile method for the synthesis of anhydroalditol alcohols. Cyclization of 2 using (R,R)-1 and (S,S)-1 proceeded diastereoselectively to form 2,5-anhydro-3,4-di-O-methyl-D-mannitol (6) and 2,5-anhydro-3,4-di-O-methyl-L-iditol (7), respectively. The cyclization of 3 and 5 is a novel method for obtaining 1,6-anhydro-3,4-di-O-methyl-D-mannitol (11) and a stereoselective route to 1,5-anhydro-3-O-methyl-L-arabinitol (13). It is proposed that the reaction occurs via endo-selective cyclization of an epoxy alcohol produced by the endo-selective ring-opening of one of the two epoxide moieties in the starting material. (c) 2005 Elsevier Ltd. All rights reserved.
  • XD Shen, N Sugie, Q Duan, Y Kitajyo, T Satoh, T Kakuchi
    POLYMER BULLETIN 55 5 317 - 322 2005年11月 [査読無し][通常論文]
     
    The reaction of cellulose with N-carbonyl alpha-amino acid ester 1 leading to cellulose carbamate 2 was carried out in N,N-dimethylacetamide at 100 degrees C. For N-carbonyl L-leucine ethyl ester (1a), the degree of the carbamate substituent (DS) in 2a was 2.5 for [1a]/[glucose units in cellulose] = 3.0 and reached ca. 3.0 for [1a]/[glucose units in cellulose] = 4.0. Cellulose carbamate 2a was highly soluble in not only aprotic polar solvents but also other organic solvents such as ethyl ether and methyl alcohol. The chiral discrimination ability of 2a was higher than those of the cellulose carbamates having L-phenylalanine and L-aspartic acid moieties.
  • R Kakuchi, R Sakai, Otsuka, I, T Satoh, H Kaga, T Kakuchi
    MACROMOLECULES 38 23 9441 - 9447 2005年11月 [査読無し][通常論文]
     
    The cyclopolymerizations of alpha,omega-diacetylene monomers, 1, 14-bis(4'-ethynylphenoxy)-3,6,9,12-tetraoxatetradecane (1) and 1,17-bis(4'-ethynylphenoxy)-3,6,9,12,15-pentaoxaheptadecane (2), were carried out in chloroform at a monomer concentration of 0.02 mol L(-1) using Rh(nbd)BPh(4) as the catalyst to afford organic-solvent-soluble and gel-free polymers. The obtained polymers were assignable to poly(phenylacetylene) derivatives with crown ether on the main chain (poly-1 and poly-2, respectively). In addition, the laser Raman spectra showed that both polymers possessed a highly cis-transoidal stereoregularity. The CD spectra of poly-1 and poly-2 in the presence of the perchloric acid salts of L-phenylglycine (L center dot Pgly center dot HClO(4)) showed a characteristic induced CD (ICD) in the UV-vis absorption region of the polymer backbone from 290 to 530 nm, and the CD patterns of both polymers in the presence Of D-and L center dot Pgly center dot HClO(4) were mirror images. Like other dynamic helical polymers, the amount of a guest, temperature, and solvent had significant influences on the induced helical structure.
  • A Narumi, S Yamane, Y Miura, H Kaga, T Satoh, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 43 19 4373 - 4381 2005年10月 [査読無し][通常論文]
     
    Star-shaped polystyrenes with acetyl glucose in the periphery and interior were synthesized via two-steps, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated living radical polymerizations. In the first step, styrene (St) was polymerized with 4-[1'-(2",2",6",6"-tetramethyl-1"-piperidinyloxy)ethyl]phenyl 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside, 1, at 120 C to afford a TEMPO-terminated polystyrene with acetyl glucose in the chain-end, arm-polymer 2. Similarly, St was polymerized with 1-phenyl-1-(2',2',6',6'-tetramethyl-1'-piperidinyloxy)ethane, 3, to obtain a TEMPO-terminated polystyrene, arm-polymer 4. In the second step, the coupling reaction of arm-polymer 2 was performed using divinylbenzene (DVB) as a linking agent in m-xylene at 138 C, giving a star-shaped polystyrene with acetyl glucose in the periphery, 5. The coupling reaction of arm-polymer 4 with DVB was carried out in the presence of 1, which produced a star-shaped polystyrene with acetyl glucose in the interior, 6. Dynamic laser light scattering (DLS) measurements indicated that 5 and 6 existed as the particles in toluene with the average diameters ranging from 12-40 nm. The numbers of the arm (N-arm) were 12-23 and 6-64 for 5 and 6, respectively, which were determined by their isolated yields and static laser light scattering (SLS) measurements. The numbers of the acetyl glucose units (N-1) were 12-23 and 9-104 for 5 and 6, respectively, which were determined from specific rotation ([alpha](365)). Finally, 5 and 6 were modified by deacetylation using sodium methoxide, producing star-shaped polystyrenes with glucose in the periphery and interior, 7 and 8, respectively. The final architectures were found to entrap a hydrophilic molecule at their glycoconjugated periphery or interior in good solvents for polystyrene such as chloroform. (c) 2005 Wiley Periodicals, Inc.
  • Y Miura, A Narumi, S Matsuya, T Satoh, Q Duan, H Kaga, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 43 18 4271 - 4279 2005年09月 [査読無し][通常論文]
     
    The synthesis of an AB(20)-type heteroarm star polymer consisting of a polystyrene arm and 20-arms of poly(methyl methacrylate) or poly(tert-butyl acrylate) was carried out using the combination of nitroxide-mediated polymerization (NMP) and atom transfer radical polymerization (ATRP). The NMP of styrene was carried out using mono-6-[4-(1'-(2 '',2 '',6 '',6-tetramethyl-1 ''-piperidinyloxy)ethyl)benzamido]-beta-cyclodextrin peracetate (1) to afford end-functionalized polystyrene with an acetylated beta-cyclodextrin (beta-CyD) unit (prepolymer 2) with a number-average molecular weight (M-n) of 11700 and a polydispersity (M-w/M-n) of 1.17. After deacetylation of prepolymer 2, the resulting polymer was reacted with 2-bromoisobutyric anhydride to give endfunctionalized. polystyrene with 20(2-bromoisobutyrol)s beta-Cyl), macroinitiator 4. The copper (I)-mediated ATRP of methyl methacrylate (MMA) and tert-butyl acrylate (tBA) was carried out using macroinitiator 4. The resulting polymers were isolated by SEC fractionation to produce AB(20)-type star polymers with a beta-CyD-core, 5. The well-defined structure of 5 with weight-average molecular weight (M-w)s of 13,500-65,300 and M-w/M-n's of 1.26-1.28 was demonstrated by SEC and light scattering measurements. The arm polymers were separated from 5 by destruction with 28 wt % sodium methoxide in order to analyze the details of their characteristic structure. (c) 2005 Wiley Periodicals, Inc.
  • T Satoh, T Imai, N Sugie, H Hashimoto, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 43 18 4118 - 4125 2005年09月 [査読有り][通常論文]
     
    The polymerizations of the diepisulfides 1,2:5,6-diepithio-3,4-di-O-methyl-D-mannitol (1a), 1,2:5,6-diepithio-3,4-di-O-methyl-L-iditol (1b), and 1,2:5,6-diepithio-3,4-di-0-methyl-allitol (1c) were carried out with ZnEt2/H2O, ZnEt2/alcohol, and ZnEt2/(S or R)-1,1'-bi-2-naphthol (BN) as the initiator systems. All the polymerizations proceeded without any gel formation and gave white, powdery products. The number-average molecular weights of the obtained polymers were changed in the range of 5300-33,600. The polymerization of la using the ZnEt2/H2O (1/1) catalyst in tetrahydrofuran proceeded through a regio- and stereoselective cyclopolymerization mechanism to produce thiosugar polymers mainly consisting of 2,5-anhydro-1,5dithio-D-glucitol as the five-membered ring units. The polymers obtained from 1b and 1c with ZnEt2/H2O exhibited lower stereoregularities than that from la. For the polymers obtained from la with the ZnEt2/alcohol systems, the molar fraction of the five-membered ring units depended on the alcohol used as a ligand. On the other hand, the polymerization of le using ZnEt2/(R or S)-BN asymmetrically proceeded, and optically active polymers consisting of desulfurized acyclic units were obtained. When ZnEt2/(R)-BN (1/1) was used in toluene, the polymer with [alpha](D)(23) = +56.9 degrees was obtained in an 88.6% yield. The resulting polymer had an isotactic-rich structure consisting of about 90% (R)-configurational units and about 10% (S)-units. (c) 2005 Wiley Periodicals, Inc.
  • Depolymerization of glucan through microwave-assisted heating
    Harumi Kaga, Atsushi Narumi, Masakatsu Miura, Kenji Takahashi, Toshifumi Satoh, Toyoji Kakuchi
    Proceedings of 7th Austrian Polymer Meeting 90  Proceedings of 7th Austrian Polymer Meeting 2005年07月 [査読無し][通常論文]
  • T Satoh, T Imai, H Ishihara, T Maeda, Y Kitajyo, Y Sakai, H Kaga, N Kaneko, F Ishii, T Kakuchi
    MACROMOLECULES 38 10 4202 - 4210 2005年05月 [査読無し][通常論文]
     
    The ring-opening multibranching polymerizations of 1,6-anhydro-β-D-glucopyranose (1) and 1,6-anhydro-β-D-galactopyranose (2) have been studied in order to synthesize hyperbranched polysaccharides. The solution polymerization in propylene carbonate and the bulk polymerization of 1 and 2 using a thermally induced cationic initiator proceeded through a ring-opening reaction and a proton transfer reaction to afford highly water-soluble polysaccharides, i.e., poly-1 and poly-2, respectively. For the polymers from 1 and 2 with the same polymerization conditions, the M-w,M-SLS and yield of poly-1 were higher than those of poly-2. Here, poly-1 and poly-2 were characterized as hyperbranched polysaccharides consisting of α- and β-linked D-hexopyranosyl and D-hexofuranosyl repeating units, hyperbranched D-glucan and D-galactan, respectively. In addition, poly-1 and poly-2 had ca. 30-40 mol % nonreducing D-hexopyranosyl and D-hexofuranosyl terminal units, and the degree of branching was ca. 0.38 for poly-1 and 0.44-0.60 for poly-2. The respective viscosities of poly-1 and poly-2 in aqueous NaNO3(0.2 mol(.)L(-1)) solution were very low with the intrinsic viscosity values of 0.023-0.042 dL(.)g(-1). The steady shear flow of poly-1 in aqueous solution exhibited a Newtonian behavior with steady shear viscosities independent of the shear rate, even at high concentrations. The results indicated that the characteristics of the viscosities were attributed to the spherical structure of the hyperbranched polysaccharide in aqueous solution.
  • T Imai, Y Nawa, Y Kitajyo, T Satoh, H Kaga, N Kaneko, T Kakuchi
    MACROMOLECULES 38 5 1648 - 1654 2005年03月 [査読無し][通常論文]
     
    2,3-Anhydroerythritol (1a) and 2,3-anhydro-DL-threitol (1b) were polymerized using boron trifluoride diethyl etherate (BF3.OEt2) as a cationic initiator. The polymerizations of 1a and 1b proceeded through a ring-opening reaction with a proton-transfer reaction to produce hyperbranched carbohydrate polymers (2a and 2b) consisting of DL-threitol and erythritol units, respectively. The degrees of branching (DBs) estimated by the C-13 NMR spectra of 2a and 2b were 0.47 and 0.45, respectively. The weight-average molecular weight (M-w,M-SLS) values (2.67 x 10(5)-3.20 x 10(6)) estimated using static light scattering (SLS) of the resulting hyperbranched carbohydrate polymers were significantly higher than the weight-average molecular weight (M,,SEC) values (1.04 x 10(3)-2.77 x 10(3)) estimated using size exclusion chromatography (SEC). The viscosities of 2a and 2b in aqueous sodium nitrate (NaNO3) solution were very low, and the intrinsic viscosities ([eta]) of 2a and 2b were in the range from 0.0190 to 0.0250 dL g(-1). The three-dimensional properties characterized by the SLS and viscosity measurements indicated that 2a and 2b should be spherical molecules.
  • Y Miura, T Satoh, A Narumi, O Nishizawa, Y Okamoto, T Kakuchi
    MACROMOLECULES 38 4 1041 - 1043 2005年02月 [査読無し][通常論文]
  • 多分岐糖鎖を用いた機能性医用材料の創製~より安全で、高性能な医用材料を目指して~
    創成ニューズレター (北海道大学) 2 17 - 19 2005年 [査読無し][通常論文]
  • 佐藤敏文, 佐藤敏文
    化学と生物 43 12 778 - 779 2005年 [査読無し][通常論文]
  • 石戸総, 青木登和子, 佐藤敏文, 覚知豊次
    高分子加工 54 1 2 - 6 高分子刊行会 2005年 [査読無し][通常論文]
  • Satoh Toshifumi, Imai Tomoko, Kitajyo Yoshikazu, Kakuchi Toyoji, Bregg RK
    Current Topics in Polymer Research 195 - 231 2005年 [査読有り][通常論文]
  • H Kaga, S Yamane, A Narumi, T Satoh, T Kakuchi
    MACROMOLECULAR SYMPOSIA 217 29 - 38 2004年10月 [査読無し][通常論文]
     
    2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) was reacted with 4-ethylphenyl 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside using tert-butyl hydroperoxide and cobalt(II)acetate tetrahydrate in acetonitrile. The reaction provided 4-[1'-(2",2",6",6"-tetramethyl-1"-piperidinyloxy)-ethyl]phenyl 2,3,4,6-tetra- O-acetyl-beta-D-glucopyranoside, glycoconjugated initiator. Star-shaped polystyrene architectures in which glucose was covalently bonded in the core and chain-end were successfully prepared from the glycoconjugated initiator, styrene, and 1,4-divinylbenzene as starting materials.
  • T Satoh, T Imai, Y Kitajyo, T Maeda, A Narumi, H Kaga, N Kaneko, T Kakuchi
    MACROMOLECULAR SYMPOSIA 217 39 - 46 2004年10月 [査読無し][通常論文]
     
    The thermally induced cationic polymerizations of 1,6-anhydro-beta-D-glucopyranose (1a), 1,6-anhydro-beta-D-mannopyranose (1b) and 1,6-anhydro-beta-D-galactopyranose (1c) as a latent cyclic AB(4)-type monomer were carried out using (S-2-butenyl)tetramethylenesulfonium hexafluoroantimonate (2) as an initiator. The solution polymerization in propylene carbonate proceeded without gelation to produce the water-soluble hyperbranched polysaccharides (3a-c) with controlled molecular weights and narrow polydispersities. The degree of branching (DB), estimated by the methylation analysis of 3a-c, was in the range of 0.38 - 0.49. The thermally induced cationic polymerization of 1a-c using 2 is a facile method leading to a hyperbranched polysaccharide with a high DB value.
  • M Tsuji, T Aoki, R Sakai, T Satoh, H Kaga, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 42 18 4563 - 4569 2004年09月 [査読無し][通常論文]
     
    The enantiomer-selective radical polymerization of rac-2,4-pentanediyl dimethacrylate, an equimolar mixture of (2S,4S)-2,4-pentanediyl dimethaerylate (SS-1) and (2R,4R)-2,4-pentanediyl dimethacrylate (RR-1), was carried out with a chiral atom transfer radical polymerization initiating system consisting of methyl 2-bromoisobutyrate (3), dichlorotris(triphenylphosphine)ruthenium [RuCl2(PPh3)(3)], and a chiral additive in anisole at 60 degreesC. When (S)-1,1'-bi-2-naphthol (a-3) was used as the chiral additive, the recovered monomer was enriched in SS-1, and the enantiomeric excess was 16.9% at a 22.6% monomer conversion. The specific rotation ([alpha](435), c 0.3, CHCl3) of the resulting polymer was +40.3degrees at a 22.6% monomer conversion. For the copolymerization of SS-1 and RR-1 with 3/RuCl2(PPh3)(3)/a-3 in anisole at 60 degreesC, the monomer reactivity ratio for RR-1 (r(R)) was determined to be 4.94, and that for SS-1 (r(S)) was 0.27. For the homopolymerizations of SS-1 and RR-1 with 3/RuCl2(PPh3)(3)/a-3 in anisole at 60 degreesC, the polymerization rate of RR-1 was considerably faster than that of SS-1, and the rate constants for the homopolymerizations were determined to be k(SS) = 2.0 x 10(-3) h(-1) and k(RR) = 8.2 x 10(-3) h(-1), respectively. With the values of k(SS), k(RR), r(R), and r(S), the relative ratio k(SS)/k(RR)/k(SR)/k(RS) was determined to be 1.2:4.9:4.5:1, which indicated that both the growing end of SS-1 and that of RR-1 preferentially reacted with RR-1. (C) 2004 Wiley Periodicals, Inc.
  • R Sakai, T Satoh, R Kakuchi, H Kaga, T Kakuchi
    MACROMOLECULES 37 11 3996 - 4003 2004年06月 [査読無し][通常論文]
     
    Polymerization of a novel alpha,omega-diisocyanate monomer, 1,14-bis(4-isocyanatophenoxy)-3,6,9,12-tetraoxatetradecane (1), was carried out in DMF using MeLi to afford a gel-free linear polymer according to a cyclopolymerization mechanism. The resulting polymer was assignable to poly(phenyl isocyanate) with a C-2 symmetrical crown cavity on the main chain (2). The circular dichroism (CD) spectrum of 2 in the presence of the perchloric acid salt Of L-phenylglycine (L-Pgly.HClO4) showed a negative Cotton effect with a high intensity of -3.2 x 10(4) deg cm(2) dmol(-1) in the range from 245 to 330 nm, corresponding to the absorption of the polymer backbone, while a positive Cotton effect was observed for D-Pgly.HClO4, and the CD spectrum pattern was a mirror image of that of 2 with L-Pgly-HClO4. Thus, this suggested that the novel type of poly(phenyl isocyanate) with the crown cavity on the main chain (2) formed a one-handed helical structure driven by the host-guest complexation with the chiral guest molecules. Although the solvent significantly influenced the CD intensities of 2, the CD intensities hardly changed at any temperature.
  • T Imai, T Satoh, H Kaga, N Kaneko, T Kakuchi
    MACROMOLECULES 37 9 3113 - 3119 2004年05月 [査読無し][通常論文]
     
    1,4-Anhydroerythritol (1a) and 1,4-anhydro-L-threitol (1b) were polymerized using trifluoromethanesulfonic acid (CF3SO3H) or fluorosulfonic acid (FSO3H) as a cationic initiator. The polymerizations of la and 1b, proceeded through a ring-opening reaction with a proton-transfer reaction to produce hyperbranched carbohydrate polymers (2a and 2b) mainly consisting of erythritol and L-threitol units, respectively. The degrees of branching (DB) estimated by the C-13 NMR spectra of 2a and 2b were ca. 0.28-0.47. The weight-average molecular weight (M-w,(SLS)) values (3.2 X 10(4) - 5.1 x 10(5)) estimated using static laser light scattering (SLS) of the resulting hyperbranched carbohydrate polymers were significantly higher than the weight-average molecular weight (M,SEC) values (1.5 x 10(3)-1.4 x 10(4)) estimated using size exclusion chromatography (SEC). The solution viscosities of 2a and 2b were very low, and the intrinsic viscosities ([eta]) of 2a and 2b were in the range from 3.26 x 10(-2) to 7.30 x 10(-2) dL.g(-1). The three-dimensional properties characterized by the SLS and viscosity measurements indicated that 2a and 2b should be nanoscale particles.
  • 植物由来の原料を利用した新しい医療用ゲル材料の開発~より安全な外科用接着剤、止血剤を目指して~
    創成ニューズレター (北海道大学) 1 9 - 9 2004年 [査読無し][通常論文]
  • 佐藤敏文, 今井知子, 北城喜一, 覚知豊次
    Foods & Food Ingredients Journal of Japan 209 5 397 - 403 FFIジャーナル編集委員会 2004年 [査読無し][通常論文]
  • 辻雅司, 堺井亮介, 青木登和子, 佐藤敏文, 加我晴生, 覚知豊次
    高分子論文集 61 4 269 - 274 高分子学会 2004年 [査読無し][通常論文]
     
    The enantiomer-selective radical polymerization of rac-2,4-pentanediyl dimethacrylate (rac-1) was carried out using methyl 2-bromoisobutylate (3) /Ru catalyst (Ru-X) /chiral additive (A-X) as the chiral atom transfer radical polymerization (ATRP) initiating system in anisole at 60 degreesC. The chiral metal complex affected the enantiomer selectivity, e.g., when (S)-1, 1'-bi-2-naphthol (A-4) was used as the chiral additive, (2R,4R)-2,4-pentanediyl dimethacrylate (RR-1) was predominantly consumed and the enantiomeric excess of the recovered monomer was 16.9% at 22.6% of a monomer conversion. The enantiomeric excess of the recovered monomer increased with the increasing monomer conversion, and the specific rotation of the resulting polymers decreased. In conclusion, we achieved the enantiomer-selective polymerization by cyclopolymerizing rac-1 by the ATRP method using the chiral initiating system.
  • T Satoh, T Kakuchi
    PROGRESS IN POLYMER SCIENCE 29 1 13 - 43 2004年01月 [査読有り][通常論文]
     
    The regio- and stereoselective cyclopolymerization of 1,2:5,6-dianhydrohexitol, 1,2:4,5-dianhydropentitol, and 1,2:5,6-diepithio-1,2:5,6-tetradeoxy-hexitoI has been studied as a new synthetic method for preparing artificial carbohydrate polymers lacking an anomeric linkage, quite different from the structure of naturally occurring polysaccharides. The carbohydrate polymers consisting of (1 --> 6)-linked 2,5-anhydrohexitol as five-membered ring units were formed by the cyclopolymerizations of 1,2:5,6-dianhydro-3,4-di-O-alkyl-D-mannitol, -L-iditol, -D-glucitol, and -allitol, while the formation of six-membered ring units was found in a polymer prepared by the cyclopolymerization of 1,2:5,6-dianhydro-3,4-di-O-alkyl-galactitol. In addition, the anionic cyclopolymerization of 1,2:5,6-dianhydrohexitol produced a well-defined carbohydrate polymer. The cationic cyclopolymerization of 1,2:4,5-dianhydro-3-0-methylxylitol proceeded regio- and stereoselectively to produce a novel carbohydrate polymer consisting of mainly (2 --> 5)-linked 1,4-anhydro-3-O-methyl-DL-arabinitoI as five-membered ring units. The cationic and anionic cyclopolymerizations of 1,2:5,6-diepithio-1,2,5,6-tetradeoxy-3,4-di-O-methyl-D-mannitoI and 1,2:5,6-diepithio-1,2,5,6-tetradeoxy-3,4-di-O-methyl-L-iditoI were a novel method for producing sulfur-containing carbohydrate polymers, i.e. thiosugar polymers. These carbohydrate polymers acted as a macromolecular ionophore, which exhibited size-selective cation-binding ability for metal cations and chiral discrimination ability for racemic amino acid derivatives. They were applied to optical resolution systems as liquid and solid membranes and, chiral stationary phase in HPLC. (C) 2004 Elsevier Ltd. All rights reserved.
  • T Imai, T Satoh, H Kaga, N Kaneko, T Kakuchi
    MACROMOLECULES 36 17 6359 - 6363 2003年08月 [査読無し][通常論文]
     
    The cyclopolymerization of 1,2:5,6-dianhydro-D-mannitol (1) was carried out using (BF3OEt2)-O-. and t-BuOK. Although the anionic polymerization tended to form gels, the cationic polymerization proceeded through the proton-transfer reaction mechanism to produce hyperbranched carbohydrate polymers (2) mainly consisting of 2,5-anhydro-D-glucitol units. The weight-average molecular weight (M-w,(SLS)) values of 2 measured by static light scattering (SLS) varied in the range of 2.08 x 10(5)-26.9 x 10(5), which were significantly higher than the weight-average molecular weight (M-w,M-SEC) values by size exclusion chromatography (SEC). The degree of branching (DB), estimated by the C-13 NMR measurements, was ca. 0.44-0.46. The alpha value of the Mark-Houwink equation, which was determined by the viscosity measurements, was ca. 0.3. The hyperbranched polymers 2 were nanoscale particle with the radii of gyration (R-g) of 67.4-132.0 nm.
  • SATOH T, IMAI T, ISHIHARA H, MAEDA T, KITAJYO Y, NARUMI A, KAGA H, KANEKO N, KAKUCHI T
    Macromolecules 36 17 6364 - 6370 2003年08月 [査読無し][通常論文]
     
    The thermally induced cationic polymerization of 1,6-anhydro-beta-D-mannopyranose (1) as a latent cyclic AB(4)-type monomer was carried out using 2-butenyltetramethylenesulfonium hexafluoroantimonate (2) as the initiator. The solution polymerization in propylene carbonate proceeded without gelation to produce the water-soluble hyperbranched polysaccharides (3) with controlled molecular weights and narrow polydispersities. The weight-average molecular weight (M-w,M-SLS) values of 3 measured by static laser light scattering (SLS) varied in the range 6.5 x 10(3) to 6.4 x 10(5), which were significantly higher than the weight-average molecular weight (Mw,SEC) values by size exclusion chromatography (SEC). The viscosity of the solution of 3 was very low, and the intrinsic viscosities were from 0.032 to 0.047 dL(.)g(-1). Polymer 3 was composed of alpha- and beta-linked hyperbranched polysaccharides consisting of 19 kinds of D-mannopyranosyl and D-mannofuranosyl repeating units, which had numerous nonreducing D-mannopyranosyl terminal units. The degree of branching (DB), estimated by the methylation analysis of 3, was in the range of 0.38-0.44. The thermally induced cationic polymerization of 1 using 2 is a facile method leading to the hyperbranched polysaccharide with a high DB value.
  • KAKUCHI T, NARUMI A, MATSUDA T, MIURA Y, SUGIMOTO N, SATOH T, KAGA H
    Macromolecules 36 11 3914 - 3920 2003年06月 [査読無し][通常論文]
     
    beta-Cyclodextrin (-CyD) was modified into a seven-functional initiator (1) for 2,2,6,6-tetramethylpiperidinyloxy- (TEMPO-) mediated living radical polymerization. Styrene (St) was polymerized with 1 under several conditions to afford original products I-IV. Size exclusion chromatography (SEC) traces of I-IV exhibited trimodal molecular weight distributions; hence, they were fractionated into the respective three species, i.e., main products 2, byproducts 3 with lower molecular weights, and byproducts 4 with higher molecular weights. The weight-average molecular weights determined by SEC and static laser light scattering measurement (M-w,M-SEC and M-w,M-SLS,M- respectively) were 1.34 x 10(4) and ;2.98 x 10(4) for 2-I, 4.52 x 10(4) and 6.77 x 10(4) for 2-II, 1.35 x 10(5) and 1.87 x 10(5) for 2-III, and 9.67 x 10(5) and 1.89 x 10(6) for 2-IV. The M-w,M-SLS's were larger than the respective M-w,M-SEC's. In the H-1 NMR spectra of 2, the signals due to polystyrene (PSt) appeared along with the characteristic signals due to the 1 unit. therefore, those of 2 were assignable to a star PSt with an acetylated beta-CyD core. Polymer 2 was treated with sulfuric acid to give. core-cleaved polymer 2'. The M-w,M-SEC's were 2.80 x 10(3), 9.60 x 10(3), 2.70 x 10(4), and 2.61 x 10(5) for 2'-I, 2-II, 2'-III, and 2'-IV, indicating that the arm number of 2, N-PSt, was seven. The byproducts 3 and 4 were characterized and found to be a TEMPO-terminated linear PSt and a star-star coupled polymer, respectively. The seven-arm star PSt with a beta-CyD core, 5, was obtained through deacetylation of 2 using sodium methoxide in dry THF. The M-w,M-SLS values were 3.96 x 10(5), 3.78 x 10(5), 2.40 x 10(5), and 1.94 x 10(6) for 5-I, 5-II, 5-III, and 5-IV. Hence, 5-I and 5-II showed aggregation in a good solvent for PSt with aggregation-numbers (N-A) of 13 and 6, respectively.
  • KAKUCHI T, NARUMI A, MIURA Y, MATSUYA S, SUGIMOTO N, SATOH T, KAGA H
    Macromolecules 36 11 3909 - 3913 2003年06月 [査読無し][通常論文]
     
    2,2,6,6-Tetramethylpiperidinyloxy (TEMPO)-substituted beta-cyclodextrin (beta-CyD), 1, was synthesized as the initiator for the nitroxide-mediated living radical polymerization. Styrene (St) was polymerized with 1 using a molar ratio of St and 1 in a feed ([St]/[1]) of 200 at 120 degreesC for 6 h. The size exclusion chromatography (SEC) trace of the product exhibited a symmetrical peak with a weight-average molecular weight (M-w,SEC) of 11400 and a polydispersity (M-w/M-n) of 1.13. In the H-1 NMR spectrum of the product, the signals due to polystyrene (PSt) appeared along with the characteristic signals due to the 1 unit. Thus, the product was assignable to the end-functionalized PSt with acetylated beta-CyD, 2. The introduction of acetylated beta-CyD into 2 was found to occur in a quantitative fashion, which was confirmed by thin-layer chromatography equipped with a flame ionization detector (TLC-FID). For the [St]/[1] of 600 at 120 degreesC, the St/1 system proceeded in a controlled manner to afford 2 with polymerization times of 1.5-9 h with yields of 5-40% and M-w,M-SEC's of 7500-26 000. On the other hand, the St/1 system for 15 and 20 h afforded polymers with 54 and 75% though an unexpected side reaction occurred. Polymer 2 with M-w,SEC'S of 7500-26 000 was modified by deacetylation using sodium methoxide in dry THF into end-functionalized PSt with beta-CyD, 3. Particle formation was observed during dynamic laser light scattering measurements of 3 in benzene, indicating that 3 was stably suspended in a good solvent for PSt by forming aggregates with beta-CyD as a core. The average aggregation numbers (N-A) of the aggregates were found to range from 42 to 125, which were determined by static laser light scattering measurement.
  • R Sakai, T Satoh, R Kakuchi, H Kaga, T Kakuchi
    MACROMOLECULES 36 10 3709 - 3713 2003年05月 [査読無し][通常論文]
     
    The macromolecular helicity induction of a novel optically inactive poly(phenyl isocyanate) bearing crown ether as a host group (2) based on host-guest complexation was discussed. 4'-Isocyanatobenzo-18-crown-6 (1) was polymerized with MeLi in THF at -78 degreesC to afford 2 with 71% yield. The circular dichroism (CD) spectrum of 2 in the presence of the perchloric acid salt of L-phenylalanine (L-Phe.HClO4) showed a negative Cotton effect with the high intensity of -3.7 x 10(4) deg cm(2) dmol(-1) in the range from 240 to 340 nm, corresponding to the absorption of the polymer backbone, while a positive Cotton effect was observed for D-Phe.HClO4 and the CD spectrum pattern was the mirror image of that of 2 with L-Phe.HClO4, On the other hand, a clear Cotton effect was not observed at all in the range from 230 to 290 nm for the unimer of 2,4'-(N,N-diacetylamino)benzo-18-crown-6 (3), with L-Phe.HClO4, though the cation-binding property of 3 was almost the same as that of 2, indicating that the induced CDs were based on not the inclusion of the chiral guest in the host group but the structure change in the main chain, i.e., the macromolecular helicity induction for 2 through the host-guest interaction. The helical structure of 2 was significantly affected by the molar ratio of the guest and host, the temperature change, and the type of guests.
  • A Narumi, K Kawasaki, H Kaga, T Satoh, N Sugimoto, T Kakuchi
    POLYMER BULLETIN 49 6 405 - 410 2003年03月 [査読無し][通常論文]
     
    The potato phosphorylase-catalyzed polymerization of alpha-D-glucose-I-phosphate (G-1-P) onto poly [styrene-block-(4-vinylbenzyl maltohexaoside)] (1) was performed at the molar ratios of [G-1-P](0) and [maltohexaose](0) of 35, 80, and 250. The product was found to be soluble in dimethyl sulfoxide, which was a good solvent for amylose, and showed the complex-formation with iodine, indicating that the product was assignable to poly[styrene-block-(styrene-graft-amy lose)] (2). The quantitative analysis of the liberated phosphoric acid gave the average degree of polymerization of the glucose unit (n) as 27, 51, and 180 for 2-I, 2-II, and 2-III, respectively.
  • T Satoh, H Ishihara, H Sasaki, H Kaga, T Kakuchi
    MACROMOLECULES 36 5 1522 - 1525 2003年03月 [査読無し][通常論文]
     
    A novel ladder polymer, i.e., a "fused 15-crown-4 polymer", has been synthesized by a two-step polymerization of 3-ethyl-3-oxiranylmethoxymethyloxetane (1). The anionic polymerization of 1 produced the polyoxirane (2) with multiple pendant oxetanyl groups. The second cationic cyclopolymerization of 2 homogeneously proceeded to form gel-free polymers (3), i.e., "fused 15-crown-4 polymers", having M(n)s of ca. 13 000 in 60-90% yield. The cation-binding ability of 3 has also been evaluated by a liquid-liquid extraction method using picrates of alkali, alkaline-earth, and transition metals. The metal cation-binding property of 3 strongly depended on the metal cation radius. For 3 having an M. of 13 200 and M-w/M-n of 2.42, the extraction yields of Li+, CO2+, Ni2+, and Cu2+ (with radii of 0.68-0.72 Angstrom) were relatively high. Ion selectivity values were similar to those of 14-crown-4.
  • より安全な医療材料を目指して
    リテラポプリ(北海道大学) 16 9 - 10 2003年 [査読無し][通常論文]
  • N Sugimoto, A Narumi, T Satoh, H Kaga, T Kakuchi
    POLYMER BULLETIN 49 5 337 - 340 2003年01月 [査読無し][通常論文]
     
    2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) was reacted with ethylbenzene (1a), 1-bromo-4-ethylbenzene (1b), and 4-ethylphenyl acetate (1c), respectively, using tert-BuOOH/Co(OAc).4H(2)O in acetonitrile at room temperature. The reactions produced the respective TEMPO-adducts (2a, 2b, and 2c) in the yields of 37, 44, and 45 %, which were based on TEMPO. Similarly, TEMPO was reacted with 4-ethylphenyl 2,3,6,2',3',4',6'-hepta-O-acetyl-beta-D-cellobioside (1d) to afford the glycoconjugated TEMPO-adduct (2d) in 45 % yield, which was based on 1d. These results indicated that the reaction has the potential to become an easy and also safe strategy, which provided various functionalized alkoxylamines.
  • T Kakuchi, M Tsuji, T Satoh
    ADVANCES IN CONTROLLED/LIVING RADICAL POLYMERIZATION 854 206 - 220 2003年 [査読有り][通常論文]
     
    The enantiomer-selective radical cyclopolymerization of the racemic mixture of (2R,4R)-2,4-pentanediyl dimethacryrate (RR-1) and (2S,4S)-2,4-pentanediyl dimethacrylate (SS-1) was achieved using chiral atom transfer radical polymerization (ATRP) initiating systems. RR-1 and SS-1 were predominantly polymerized using methyl 2-bromoisobutyrate /CuBr/(S,S)-2,6-bis(4-isopropyl-2-oxazolin-2-yl)pyridine and methyl 2-bromoisobutyrate/RuCl2(PPh3)(3)/(S)-1,1'-bi-2-naphthol, respectively. The enantiomer selectivity ratio was 1.3 similar to 3.2 for the Cu-catalyzed ATRP initiating system and ca. 1.0 similar to 3.4 for the Ru-catalyzed ATRP initiating system.
  • T Imai, K Hayakawa, T Satoh, H Kaga, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 40 20 3443 - 3448 2002年10月 [査読無し][通常論文]
     
    Enantiomer-selective polymerization of (RS)-(phenoxymethyl)thiirane (RS-1) was carried out with ZnEt2/L-alpha-amino acid as an initiator system, and the effect of the initiator system on the enantiomer selectivity was examined with various amino acids. All polymerizations heterogeneously proceeded, and every initiating system was effective in producing optically active polymers. For the polymerization of RS-1 with diethylzinc (ZnEt2)/(L)-leucine (1/1), the conversion was 43.7% in 12 days, and the number-average molecular weight of the polymer was 18,000. The enantiomer selectivity was maximum when the molar ratio of the two components in the ZnEt2/(L)-alpha-amino acid system was 1:1. When the ZnEt2/(L)-leucine (1/1) system was used in the polymerization, the best result was obtained with an enantiomer-selectivity value of 5.36. During the polymerization, the S enantiomer was preferentially consumed, and the isotactic-rich polymer was enriched in the S configurational units produced. (C) 2002 Wiley Periodicals, Inc.
  • M Tsuji, R Sakai, T Satoh, H Kaga, T Kakuchi
    MACROMOLECULES 35 22 8255 - 8257 2002年10月 [査読無し][通常論文]
  • A Narumi, T Matsuda, H Kaga, T Satoh, T Kakuchi
    POLYMER 43 17 4835 - 4840 2002年08月 [査読無し][通常論文]
     
    4-Vinylbenzyl glucoside peracetate 1 was polymerized with alpha,alpha'-bis(2',2',6',6'-tetramethyl-1-piperidinyloxy)-1,4-diethylbenzene 2 in chlorobenzene using (IS)-(+)-10-camphorsulfonic acid anhydrous (CSA) as an accelerator ([1] = 0.4 M,[1]/[2]/[CSA] = 75/1/1.3) at 125 degreesC for 5 h. The polymerization afforded poly(4-vinylbenzyl glucoside peracetate) having TEMPO moieties on both sides of the chain ends, 3, with a molecular weight (M-wSLS) of 8500, a polydispersity index (M-w/M-n) of 1.09, and an average degree of polymerization of the I unit (x) of 17. Styrene (St) was polymerized with 3 in chlorobenzene at 125 degreesC (St/chlorobenzene = 1/2, w/w). The polymerization successfully afforded polystyrene - poly(4-vinyl glucoside peracetate) -polystyrene, 4, when the polymerization time was below about 2 h. Polymer 4 with the M-w,M-SLS of 12,500, 17,900, and 29,400, the compositions (y-x-y) of 20-17-20, 45-17-45, and 100-17-100, and the M-w/M-n of 1.12, 1.14 and 1.17 were modified by deacetylation using sodium methoxide in dry-THF into polystyrene - poly(4-vinyl glucoside peracetate) -polystyrene, 5. The solubility of polymer 5 was examined using a good solvent for polystyrene such as toluene and for the saccharide such as H2O. (C) 2002 Elsevier Science Ltd. All rights reserved.
  • A Kusuno, N Mori, T Satoh, M Miura, H Kaga, T Kakuchi
    CHIRALITY 14 6 498 - 502 2002年06月 [査読有り][通常論文]
     
    Synthetic polysaccharides, (1-->)6-alpha-D-glucopyranan (3a) and (1-->6)-alpha-D-mannopyranan (3b), were prepared by the cationic ring-opening polymerization of 1,6-anhydro-2,3,4-tri-O-allyl-beta-D-glucopyranose (1a) and 1,6-anhydro-2,3,4-O-6-allyl-beta-D-mannopyranose (1b), followed by the cleavage of the allyl ether linkage of 2,3,4-tri-O-allyl-(1-->6)-alpha-D-glucopyranan (2a) and 2,3,4-tri-O-allyl-(1-->6)-alpha-D-mannopyranan (2b), respectively. 2,3,4-Tris-O-(3,5-dimethylphenylcarbamoyl)- and 2,3,4-tris-O-(3,5-dichlorophenylcarbamoyl)-(1-->6)-alpha-D-glucopyranan (CSP-1 and CSP-2, respectively) and 2,3,4-tris-O-(3,5-dimethylphenylcarbamoyl)- and 2,3,4-tris-O-(3,5-dichlorophenylcarbamoyl)-(1-->6)-alpha-D-mannopyranan (CSP-3 and CSP-4, respectively) were prepared by the reaction of 3 with the corresponding 3,5-disubstituted phenylisocyanates and the chiral recognition abilities of CSP-1-4 as chiral stationary phases (CSPs) in high-performance liquid chromatography (HPLC) were evaluated. Racemic compounds such as trans-cyclopropanedicarboxylic acid dianilide (9), 1,2,2,2-tetraphenylethanol (10), flavanone (11), Troger's base (12), benzoin (13), and cobalt(III) tris(acetylacetonate) (14) were efficiently resolved using CSP-1-4. For comparison among CSPs, the chiral recognition properties of the (1-->6)-alpha-D-glucopyranan CSPs were different from that of the (1-->6)-alpha-D-mannopyranan CSPs, and CSP-4 exhibited the highest chiral recognition ability among the CSPs. The resolution factors of 12 and 14 were 0.42 and 0.56 for CSP-1, 0.32 and 2.16 for CSP-2, 1.80 and 0.84 for CSP-3, and 2.31 and 8.26 for CSP-4, respectively.
  • H Kaga, A Narumi, T Satoh, T Matsuda, M Sharfuddin, T Kakuchi
    MACROMOLECULAR SYMPOSIA 181 95 - 100 2002年05月 [査読無し][通常論文]
     
    Coupling reactions of TEMPO-terminated polystyrene (PS-TEMPO) with divinylbenzene were performed in the presence of vinyl saccharides 1, successfully producing star-shaped polystyrenes with glycoconjugated core 2. Amphiphilic star-shaped polystyrenes with cores containing saccharide as hydrophilic segments 3 were obtained by the deacetylation of 2, which exhibited an encapsulation ability toward methyl orange (MO) in chloroform. A positive Cotton effect was observed in the CD spectrum for the MO/3 in the adsorption area of MO, indicating that MO existed in a chiral segment, i.e., the glycoconjugated core.
  • T Kakuchi, A Kusuno, M Mori, T Satoh, M Miura, M Sharfuddin, H Kaga
    MACROMOLECULAR SYMPOSIA 181 101 - 106 2002年05月 [査読無し][通常論文]
     
    The ring-opening polymerization of 1,6-anhydro-2,3,4-tri-O-allyl-beta-D-glucopyranose (2) has been carried out using various cationic initiators. For the condition of [2]/[BF3.OEt2] = 20 at -15 degreesC for 90 h, the polymer yield, M-w and M-w/M-n of the polymer obtained were 79%, 215,600 and 3.45, respectively. In order to study the living characteristic of the polymerization of 2, the cationic ring-opening bulk polymerization initiated by trimethylsilyl trifluoromethanesulfonate (TMSOTf) was carried out under the condition of [2]/[TMSOTf] = 1000 at -15 degreesC. The M-w, value increased in proportion to conversion until c.a. 30% and below. The M-w/M(n)s of resulting polymers were very narrow, e.g., the M-w/M-n value was 1.2 and below, which was smaller than that for the solution polymerization using BF3.OEt2. These results indicated that the ring-opening bulk polymerization of 2 using TMSOTf was living-like.
  • T Satoh, T Imai, N Sugie, R Nonokawa, K Yokota, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 40 8 965 - 970 2002年04月 [査読無し][通常論文]
     
    The bulk cyclopolymerization of diepisulfide, 1,2:5,6-diepithio-3,4-di-O-methyl-1,2:5,6-tetradeoxy-D-mannitol (1), was studied using R4N+Br (R = -CH3, C2H5, C3H7, C4H9, and C7H15) and (C4H9)(4)N+X- (X = Cl, I, NO3, and ClO4) as the initiators. All the bulk polymerizations of 1 using quaternary tetraalkylammonium salts at 90 degreesC proceeded without gelation even at high conversion to produce gel-free polymers consisting of 2,5-anhydro-1,5-dithio-D-glucitol (I) as the major cyclic repeating unit along with 1,5-anhydro-2,5-dithio-D-mannitol (II) and the desulfurized acyclic unit (III) as the minor units. The polymerization rate and molar fraction of the I unit increased with the increasing alkyl chain length of the tetraalkylammonium cation and the increasing nucleophilicity of the counteranion. Tetrabutylammonium chloride exhibited the highest catalytic activity and the highest stereoselectivity, that is, the thiosugar polymer with I:II:III = 81:15:4 and a number-average molecular weight of 31.9 x 10(3) was obtained in 85% yield for a polymerization time of 0.5 h. (C) 2002 Wiley Periodicals, Inc.
  • A Narumi, T Satoh, H Kaga, T Kakuchi
    MACROMOLECULES 35 3 699 - 705 2002年01月 [査読無し][通常論文]
     
    Coupling reactions of 2,2,6,6-tetramethylpiperidinyloxy-terminated polystyrene (PS-TEMPO) using divinylbenzene (DVB) as a linking agent were performed in the presence of 4-vinylbenzyl glucoside peracetate (1a) and 4-vinylbenzyl maltohexaoside peracetate (1b). To prepare core-glycoconjugated starshaped polymers with various amphiphilic properties, the molar ratio of 1 and DVB in the feed (F-1, [1]/[DVB]) was changed from 0.13 to 0.38 for the coupling reaction. Star-shaped polystyrenes having 1a and lb units in their cores (2a and 2b, respectively) were obtained by purification using preparative SEC. The weight-average molecular weights determined by static laser light scattering measurements (M-w,M-SLS), the polydispersity indices determined by size exclusion chromatography (M-w/M-n), the number of polystyrene arms (N-arm), and the core-composition ratio (f(1), [1 unit]/[DVB unit]) were 2.89 x 10(5)-3.31 x 10(5), 1.36-1.38, 18, and 0.09-0.23 for 2a and 2.28 x 10(5)-2.60 x 10(5), 1.29-1.35, 11-14, and 0.05-0.17 for 2b, respectively. Amphiphilic star-shaped polystyrenes with cores containing glucose and maltohexaose as hydrophilic segments (3a and 3b, respectively), which were obtained by the deacetylation of 2a and 2b, exhibited an encapsulation ability toward water-soluble molecules, such as methyl orange (MO), in chloroform. The amounts of encapsulated MO remarkably increased with the increasing hydrophilic property of 3. A positive Cotton effect was observed in the circular dichroism spectrum for the MO/3 system in the adsorption area of MO, indicating that MO existed in a chiral segment, i.e., the glycoconjugated core.
  • A Narumi, H Kaga, K Kawasaki, Y Taniguchi, T Satoh, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 39 23 4061 - 4067 2001年12月 [査読無し][通常論文]
     
    Glucosyl styrene (1a), maltosyl styrene (1b), and maltohexaosyl styrene (1c) were prepared by the glycosylation of 4-vinylbenzyl alcohol with the corresponding glycosyl trichloroacetimidates with boron trifluoride diethyl ether complex. The copolymerizations of 1a-1c with styrene were carried out with 2,2'-azobis(2-methylpropionitrile) as an initiator in dry NN-dimethylformamide at 60 degreesC, and this was followed by deacetylation to produce amphiphilic polystyrenes with glucose (3a), maltose (3b), and maltohexaose (3c) as hydrophilic segments. 3 showed various solubility characteristics that were dependent on the content of glucose residues, especially within a range of 20-50 wt%. The solubility characteristics of 3, related to the copolymer composition, indicated that the hydrophilic property was remarkably improved with an increased number of glucose units, that is, in the order 3a < 3b much less than 3c. The results described in this article provide useful information for the design of glycoconjugated architectures with desired amphiphilic properties. (C) 2001 John Wiley & Sons, Inc.
  • 佐藤敏文, NOVAK B M
    Jasco Report 43 1 10 - 12 2001年 [査読無し][通常論文]
  • H Nakade, M Obata, M Tsuji, A Narumi, T Satoh, K Yokota, T Kakuchi
    POLYMER JOURNAL 33 12 946 - 951 2001年 [査読無し][通常論文]
     
    The molecular design and synthesis of asymmetric bifunctional monomers, 3-(S)-acryloyloxy-1-(S)-methyl-butyl methyl fumarate (1a) and 3-(R)-acryloyloxy-1-(R)-methyl-butyl methyl fumarate (1b), have been carried out in terms of a novel method of producing optically active polymers based on cyclopolymerization. The polymerization of 1 proceeded via the cyclopolymerization mechanism to yield the cyclopolymer 2 with the extent cyclization of 0,87-0.96 when the monomer concentration ([M]) in the feed was 0.3 mol L-1 or less. The number-average molecular weight (M-n) decreased with a decrease in the [M] from 8300 to 3300 for polymer 2a and from 4200 to 2400 for polymer 2b. The rotation ([alpha](435)(23), c 1.0, CHCl3) of the resulting polymers changed from + 19.3degrees to + 33.4degrees for 2a and from -26.2degrees to -34.9degrees for 2b. In order to confirm the chirality induction, the chiral pentanediyl moiety was removed from polymer 2 by saponification, and the hydrolyzed polymer was treated with diazomethane to give poly(methyl acrylate-co-dimethyl fumarate) (3). The M-n was 2200-2600 for 3a and 2300-5700 for 3b, and the template-free polymers showed an optical activity with a specific rotation that ranged from -1.4degrees to -9.3degrees for 3a and from +7.5degrees to +8.8degrees for 3b. The CD spectra of 3a showed a positive Cotton effect whereas 3b showed a negative Cotton effect which is the mirror image of 3a. The optical activity of polymer 3 should be attributed to the threo-erythro sequence of the methyl acrylate and dimethyl fumarate units.
  • A Narumi, T Matsuda, H Kaga, T Satoh, T Kakuchi
    POLYMER JOURNAL 33 12 939 - 945 2001年 [査読無し][通常論文]
     
    The polymerizations of glycoconjugated monomers, i.e., 4-vinylbenzyl glucoside peracetate (1a) and 4-vinylbenzyl maltohexaoside peracetate (1b), were carried out using 2,2,6,6-tetramethylpiperidine-1-oxyl-terminated polystyrene (PS-TEMPO, M-n = 8100 and M-w/M-n = 1.17) as a macromolecular initiator in xylene at 120degreesC ([1]/[PS-TEMPO] = 25). The M-n of the product increased from 9900 to 12700 for the polystyrene-block-poly-1a (2a) and from 14200 to 16200 for the polystyrene-block-poly-1b (2b) with the increasing polymerization time, whereas the M-w/M-n values were constant at 1.13-1.21. The deacetylation of 2a and 2b using sodium methoxide in dry-THF provided amphiphilic block copolymers containing glucose and maltohexaose as hydrophilic segments, i.e., polystyrene-block-poly(4-vinylbenzyl glucoside) (3a) and polystyrene-block-poly(4-vinylbenzyl maltohexaoside) (3b). The solution property of the block copolymers 3a and 3b in toluene (a good solvent for polystyrene) and H2O (a good solvent for saccharides) varied depending on the weight fraction of the glucose residues (f(g), wt%) in 3, i.e., 3a with an f(g)s of 4, 10, and 14 wt% formed reversed micelle-like aggregate in toluene, whereas 3a with an f(g) of 17 wt% and 3b with an f(g) of 37 and 50 wt% formed micelle-like aggregates in H2O.
  • 佐藤 敏文
    高分子 49 11 2000年11月01日 [査読無し][通常論文]
  • K Yokota, T Kakuchi, T Satoh, S Umeda, M Kamada
    MACROMOLECULAR SYMPOSIA 157 13 - 20 2000年07月 [査読無し][通常論文]
     
    The selective cyclopolymerization of 1,2:5,6-dianhydrohexitols corresponding to diepoxides was a new synthetic strategy for polycarbohydrates, though the polymer is a lack of the anomeric linkage which is found in the naturally occurring polysaccharides. 1,2:5,6-Dianhydro-3,4-di-O-methyl-D-mannitol L-iditol, and D-glucitol were polymerized using t-BuOK and BF3. OEt2, to produce the polymers consisting of five-membered rings. On the other hand, the polymers consisting of six-membered rings were obtained by the cationic and anionic polymerizations of meso allitol and galactitol monomers, respectively.
  • T Satoh, D Kitazawa, R Nonokawa, M Kamada, K Yokota
    MACROMOLECULES 33 14 5303 - 5307 2000年07月 [査読無し][通常論文]
  • 佐藤 敏文
    高分子 49 11 798 - 798 公益社団法人 高分子学会 2000年 [査読無し][通常論文]
  • 覚知豊次, 梅田哲, 佐藤敏文, 横田和明
    膜 25 6 273 - 276 日本膜学会 2000年 [査読無し][通常論文]
  • T Kakuchi, R Nonokawa, S Umeda, T Satoh, K Yokota
    MACROMOLECULES 33 2 246 - 247 2000年01月 [査読無し][通常論文]
  • Yokota K, Satoh T, Umeda S, Hashimoto H, Kakuchi T, RS
    Current Trends in Polymer Science, Vol 5 5 63 - 77 2000年 [査読有り][通常論文]
  • S Umeda, T Satoh, K Saitoh, H Kanai, M Kamada, K Yokota, T Kakuchi
    ENANTIOMER 5 5 473 - 479 2000年 [査読有り][通常論文]
     
    [(1 --> 6)-2,5-Anhydro-3,4-di-O-ethyl-D-glucitol]-bound silica gel (CSP 4a), which was prepared by a two-step reaction, was used as a chiral stationary phase in high performance liquid chromatography. The chiral recognition ability of the CSP 4a for racemates was examined using aq. NaClO4 (pH 2) and aq. NaClO4 (pH 2)/CH3CN as the eluents. For the resolution of amino acids and amino acid methyl esters, the D-isomers were eluted first. The separation factors of many of the racemates were 1.1-1.4, and the resolution factors were 0.59-7.75. This stationary phase showed a relatively high-resolving power toward compounds having a bulky substituent on the chiral carbon, such as phenyl-glycine and 1-(1-naphthyl)ethylamine.
  • M Kamada, T Satoh, T Kakuchi, K Yokota
    TETRAHEDRON-ASYMMETRY 10 19 3667 - 3669 1999年09月 [査読無し][通常論文]
     
    The asymmetric hydrations of meso-diepoxides, 1,2:4,5-dianhydro-3-0-methylxylitol 2, 1,2:5,6-dianhydro-3,4-di-O-methylallitol 3 and 1,2:5,6-dianhydro-3,4-di-O-methylgalactitol 4, were carried out using (R,R)-1 and (S,S)-1. An optically active five-membered cyclic compound was selectively produced in good yield from 2, but a mixture of the five- and six-membered cyclic compounds was obtained in the cases of 3 and 4. The ees of all cyclic products exceeded 90%. (C) 1999 Elsevier Science Ltd. All rights reserved.
  • M Kamada, T Satoh, K Yokota, T Kakuchi
    MACROMOLECULES 32 18 5755 - 5759 1999年09月 [査読無し][通常論文]
     
    The cyclopolymerizations of two meso dianhydrohexitols, 1,2:5,6-dianhydro-3,4-di-O-methylallitol (1) and -galactitol (3), were examined to form a polymer with six-membered ring repeating units. Distinct from the cases of 1,2:5,6-dianhydro-3,4-di-O-methyl-D-mannitol (5), -L-iditol (6), and -D-glucitol (7) in which the five-membered ring units were formed with high regio- and stereoselectivity, six-membered ring units were found in polymers 2b, 4a, and 4b obtained by the polymerizations of 1 and 3. The anionic polymerization of 1 with t-BuOK was highly regio- and stereoselective to form polymer 2a consisting of five-membered ring units, but that of 3 was different in the scission mode of the epoxy groups to form polymer 4a consisting essentially of six-membered ring units. The cationic polymerization of 1 with BF3. OEt2 produced polymer 2b having a structure consisting of the six-membered ring units as major constituents and five-membered ring units as minor ones. The structure of polymer 4b from the cationic polymerization of 3 was somewhat complex, comprising unknown units and uncyclized units along with the five- and six-membered ring units. The steric hindrance in the growing ion was an advantage in forming the six-membered ring unit.
  • T Satoh, K Shibata, K Yokota, T Kakuchi
    MACROMOLECULAR RAPID COMMUNICATIONS 20 2 55 - 58 1999年02月 [査読有り][通常論文]
     
    (2-->5)-1,4-Anhydro-3-O-methyl-pentitol, which is a novel carbohydrate polymer without an anomeric linkage, was synthesized by cationic cyclopolymerization of 1,2: 4,5-dianhydro-3-O-methylxylitol. When BF3 . OEt2 was used as the initiator, soluble polymers were obtained in 28 to 50% yield. These polymers have number-average molecular weights of 1150 to 2340 corresponding to an average degree of polymerization of 8.8 to 18.0. It was confirmed by C-13 NMR that the resulting polymer mainly consists of 1,4-anhydro-3-O-methyl-DL-arabinitol units.
  • KAKUCHI Toyoji, HATAKEYAMA Takeshi, KANAI Hiromitsu, SATOH Toshifumi, YOKOTA Kazuaki, HARAGUCHI Kensaku, KAGA Harumi
    Polymer journal 31 3 293 - 295 Society of Polymer Science 1999年 [査読無し][通常論文]
     
    The cation-binding property has been studied for polymer 1 consisting of 3,4-di-O-methyl-D-glucitol units, (1 --> 6)-2,5-anhydro-3,4-di-O-methyl-D-glucitol and polymer 2 with a mole fraction of cyclized units of 0.52 synthesized by the polymerization of 1,2:5,6-dianhydro-3,4-O-isopropylidene-D-mannitol. Polymer 1 exhibited cation-binding selectivity in the order of K+ > Rb+ > Cs+ >Na+ > Li+, which was estimated using both liquid-liquid extraction and liquid-membrane transport methods. On the other hand, 2 showed an extremely low cation-binding characteristic in both extraction yield and selectivity, and the yield of K+ for 2 was ca. one-eighth of that for 1. There was a need for ca. 21-25 and ca. 200-400 repeating units in the complexes of 1 and 2 with K+, respectively. The binding ability of 1 strongly depended on the radius of the metal cations, and the extraction yields were relatively low for a cation with a radius of 1.12 Angstrom and below (Mg2+, Li+, Ni2+, Co2+, Cu2+, Zn2+, Cd2+, Na+, Ca2+, and Sr2+) and high for a cation with a radius of 1.20 Angstrom and above (Pb2+, Ag+, K+, Ba2+, Rb+, and Cs+).
  • T Satoh, Y Tanaka, K Yokota, T Kakuchi
    REACTIVE & FUNCTIONAL POLYMERS 37 1-3 293 - 298 1998年06月 [査読無し][通常論文]
     
    Enantioselective permeation of racemic amino acid perchlorates has been studied using a solid membrane prepared from polyacrylonitrile-graft-(1 --> 6)-2,5-anhydro-3,4-di-O-methyl-D-glucitol. The permeation rates of the amino acids decreased in the order of phenylglycine > phenylalanine > tryptophane, according to the molecular size of the guest compounds. For all the amino acids tested, the permeation rate of the D-isomer was greater than that of the L-isomer. When D- and L-phenylglycine perchlorates were permeated, the D-isomer permeated 1.17 times faster than the L-isomer. During transport using racemic phenylglycine perchlorate, the D-isomer was permeated first and the optical purity was 75% ee (max.). For the adsorption experiment for racemic phenylglycine, the L-isomer was more strongly adsorbed than the D-isomer (5.8% ee). From these data, it was directly made clear that the (1 --> 6)-2,5-anhydro-3,4-di-O-methyl-D-glucitol moieties in the membrane preferentially interacted with the L-isomer rather than with the D-isomer. (C) 1998 Elsevier Science B.V. All rights reserved.
  • T Hatakeyama, M Kamada, T Satoh, K Yokota, T Kakuchi
    MACROMOLECULES 31 9 2889 - 2893 1998年05月 [査読無し][通常論文]
     
    The effect of 18-crown-6 ether (18C6) in the anionic cyclopolymerization of 1,2:5,6-dianhydro-3,4-di-O-methyl-D-mannitol (1) using potassium tert-butoxide (t-BuOK) was studied. The addition of 18C6 did not affect the regio-and stereoselectivity in the polymerization of 1, and the resultant polymer was (1-->6)-2,5-anhydro-3,4-di-O-methyl-D-glucitol (2). The complexation of t-BuOK with 18C6 increased the initiator efficiency from 0.3 to 1.0, which was accompanied by enhancement of the apparent polymerization rate. The rate constant ratios of the transfer reaction to the propagation (k(tr)/k(p)) in the systems with and without 18C6 were 1 order of magnitude lower than the value in the polymerization of monoepoxides. The "living" nature of the t-BuOK/18C6 initiating system was evaluated by the two-step monomer resumption experiment.
  • S Umeda, T Satoh, K Saitoh, K Yokota, T Kakuchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 36 6 901 - 909 1998年04月 [査読有り][通常論文]
     
    The cyclopolymerization of 3,4-di-O-allyl-1,2 : 5,6-dianhydro-D-mannitol (1) was carried out using BF3 . OEt2 and t-BuOK. The polymer obtained by the polymerization with BF3 . OEt2 mainly consisted of (1-->6)-bonded 3,4-di-O-alkyl-2,5-anhydro-D-glucitol as the five-membered constitutional repeating unit, though it contained a small amount of other cyclic repeating units. On the other hand, during the polymerization using t-BuOK, the stereoregular polymer (1-->6)-linked 3,4-di-0-allyl-2,5-anhydro-D-glucitol (2) was synthesized via a regio-and stereoselective mechanism. Cleavage of the allyl ether linkage in polymer 2 occurred to produce the polymer consisting of only 2,5-anhydro-D-glucitol units, i.e., (1-->6)-2,5-anhydro-D-glucitol (3). Chromatographic enantioseparation of chloroquine and troger base has been performed on (3,5-dimethylphenyl)carbamate and 4-methylbenzoate derivatives of 3 as a chiral stationary phase for high-performance liquid chromatography. (C) 1998 John Wiley & Sons, Inc.
  • SATOH T, MIURA T, HATAKEYAMA T, YOKOTA K, KAKUCHI T
    Macromole. Rapid Commun. 18 12 1041 - 1048 1997年12月 [査読無し][通常論文]
     
    End-functionalized (1-->6)-2,5-anhydro-3,4-di-O-methyl-D-glucitols (3a-c) were synthesized by the anionic cyclopolymerization of 1,2:5,6-dianhydro-3,4-di-O-methyl-D-mannitol (1), followed by treatment with a terminating agent such as 4-vinylbenzyl (2 a), oxetanyl (2b), and methacryloyl group (2c). The end-functionalization proceeded in a high efficiency at 73-98%. The radical copolymerization of styrene with 3a yielded a polymer (5 a) whose GPC trace exhibited a unimodal peak. 5a was polystyrene with (1-->6)-2,5-anhydro-3,4-di-O-methyl-D-glucitol as pendant groups whose structure was confirmed by the H-1 NMR spectrum.
  • SATOH T, KITAZAWA D, HASHIMOTO H, YOKOTA K, KAKUCHI T
    Macromolecules 30 9 2802 - 2804 1997年05月 [査読無し][通常論文]
  • 畑山猛, 鎌田匡俊, 佐藤敏文, 横田和明, 覚知豊次
    高分子論文集 54 10 710 - 715 1997年 [査読無し][通常論文]
     
    In order to clarify the differences of polymerizability among 1,2:5,6-dianhydrohexitols, characteristics of the polymerizations of 1,2:5,6-dianhydro-3,4-di-O-methyl-D-mannitol (1), -L-iditol (2), and -D-glucitol (3) with potassium tert-butoxide (t-BuOK) were compared. The apparent rat constant of polymerization decreased in the order of 1>3> 2. The polymerizations of 2 and 3 showed that chain transfer reactions occurred concurrently. End-functionalization in the polymerization of 1 proceeded in a high efficiency over 95% to yield macromonomers having a styryl group or oxetanyl group at a terminal. The result indicated that the polymerization of 1 proceeded in a living manner. The initiator efficiency in the polymerization of 1 was low (0.55) owing to the poor solubility of t-BuOK. 18-Crown-6 ether (18C6) increased the solubility of t-BuOK by forming it complex. The polymerization of 1 in the presence of 18C6 yielded the polymer with a number-average degree of polymerization (DP,) corresponding to the feed molar ratio of the monomer to the initiator ([M](0)/[I](0)).
  • 覚知豊次, 佐藤敏文, 横田和明
    有機合成化学協会誌 55 4 290 - 300 1997年 [査読有り][通常論文]
     
    Cyclopolymerization of 1,2:5, 6-dianhydrohexitol has been studied in terms of ectivity. The anionic cyclopolymerizations of 1,2:5, 6-dianhydro-D-mannitol and L-iditol produced (1 --> 6)- and (6 --> 1)-2, 5-anhydro-D-glucitol, respectively. On the other hand, the cyclopolymerizations using a cationic initiator gave the polymer consisting of 2,6-anhydro-D-glucitol as the cyclic constitutional unit along with 1,6:2, 5-dianhydro-D-glucitol as a by-product. For the cationic cyclopolymerization of 1,2:5,6-dianhpdro-D-glucitol, the resulting polymer was confirmed to have the constitutional unit mainly of 2,5-anhydro-D-mannitol, while the polymer obtained using anionic initiator consisted of two cyclic repeating units, 2; 5-anhydro-D-mannitol unit and 2, 5-anhydro-L-iditol unit. The cyclopolymerization of 1,2:5,6-dianhydrohexitol was regio- and stereoselective, i.e., the intramolecular cyclization proceeded through the alpha-scission with inversion of the configuration at the alpha-carbon and the intermolecular Propagation through the beta-scission with retention. The polymer consisting of 2,5-anhydrohexitol, a novel polymeric carbohydrate, showed a metal cation-binding ability and a chiral recognition property toward the racemic amino acid derivatives.w
  • T Kakuchi, T Satoh, H Kanai, S Umeda, T Hatakeyama, K Yokota
    ENANTIOMER 2 3-4 273 - 276 1997年 [査読有り][通常論文]
     
    (1 --> 6)-2,5-Anhydro-3,4-di-O-methyl-D-glucitol formed complexes with alkali metals and also showed a chiral recognition property for racemic amino ester salts. Here we report the covalent attachment of the polymer to silica gel and use of the designed polymeric host site to resolve amines, amino acids, and amino ester as guests by solid-liquid chromatography. The polymer bound on silica gel was prepared by a two-step reaction. The chiral recognition ability of the chiral stationary phase for racemates was examined using water (pH 2), water (pH 2)-methanol, and water (pH 2)-acetonitrile as eluents. The separation factors of many racemates were 1.1-1.2, and the resolution factors were 0.38-0.63. This stationary phase showed relatively high resolving power toward compounds having a bulky substituent on the chiral carbon, such as tryptophan and phenylglycine.
  • T Satoh, T Hatakeyama, S Umeda, M Kamada, K Yokota, T Kakuchi
    MACROMOLECULES 29 21 6681 - 6684 1996年10月 [査読無し][通常論文]
     
    The anionic cyclopolymerization of 1,2:5,6-dianhydro-3,4- di-O-methyl-L-iditol (3) was carried out using t-BuOK and KOH. The resulting polymer 4 consisted of 2,5-anhydro-3,4-di-O-methyl-D-glucitol as a five-membered repeating unit, which was identical with that of polymer 2 obtained from 1,2:5,6-dianhydro-3,4-di-O-methyl-D-mannitol (1). The copolymerization of 1 with 3 produced a random copolymer consisting of (1-->6)-, (6-->1)-, (1-->1)-, and (6-->6)-linked 2,5-anhydro-3,4-di-O-methyl-D-glucitol. These facts elucidated the presence of two Linkages during the homopolymerization of 1 and 3, i.e., the (1-->6) and (6-->1)-bonded 2,5-anhydro-3,4-di-O-methyl-D-glucitol units in polymers 2 and 4, respectively.
  • T Kakuchi, T Satoh, H Kanai, S Umeda, T Hatakeyama, H Hashimoto, K Yokota
    MACROMOLECULES 29 13 4490 - 4493 1996年06月 [査読無し][通常論文]
     
    The cyclopolymerizations of (2S,5S)-1,2:5,6-diepoxyhexane using BF3 . OEt(2) and tert-BuOK have been studied. The polymer yield and molecular weight of the polymer using tert BuOK were higher than those using BF3 . OEt(2). For the polymers using BF3 . OEt(2), the mole fractions of the cyclized units were 0.76-0.90, and the cyclic constitutional repeating units were five and six-membered rings. The polymer using tert-BuOK essentially consisted of the five-membered cyclic repeating unit.
  • SATOH T, HATAKEYAMA T, UMEDA S, HASHIMOTO H, YOKOTA K, KAKUCHI T
    Macromolecules 29 10 3447 - 3452 1996年05月 [査読無し][通常論文]
     
    The anionic cyclopolymerizations of 1,2:5,6-dianhydro-3,4-di-O-methyl-D-mannitol (1) and 1,2:5,6-dianhydro-3,4-O-isopropylidene-D-mannitol (2) have been carried out using potassium tert-butoxide (t-BuOK) and potassium hydroxide (KOH). For the polymerization of 1, a well-defined carbohydrate polymer consisting of (1-->6) linked 2,5-anhydro-3,4-di-O-methyl-D-glucitol units was synthesized through a regio- and stereoselective mechanism. When a [1]/[t-BuOK] molar ratio of 20 was used in toluene for 48 h, the yields and number-average molecular weights (M(n)) of the polymers gradually increased with polymerization time. The M(n) of the polymer varied with the molar ratio of monomer to initiator, and a linear relationship between them was found. The degree of polymerization was larger than that estimated from the molar ratio, resulting in an initiator efficiency of about 55%. KOH was also effective for converting monomer 1 to a gel-free polymer but was not as active as t-BuOK. The rate of polymerization was rather slow, and the polymerization was not complete, even after 100 h. The presence of a crown ether, 18-crown-6, in the cyclopolymerization allowed the M(n) of the polymer to approach the value estimated from the [1]/[t-BuOK] molar ratio. On the other hand, monomer 2 tended to form a gel in the polymerization process, so soluble polymers were isolated only at early stages of the polymerization.
  • T Kakuchi, S Umeda, T Satoh, K Yokota, T Yuhta, A Kikuchi, S Murabayashi
    INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES 18 1-2 147 - 148 1996年02月 [査読無し][通常論文]
     
    (1-->6)-2, 5-Anhydro-3,4-di-O-methyl-D-glucitol (2a) and (1-->6)-2,5-anhydro-D-glucitol (2c) and its sulfated derivative (2d) were synthesized and their biological activities were evaluated in regards to the effects on murine lymphocytes. The polymers showed different effects on the lymphocytes depending on the substituent groups. The sulfated polymer (2d) induced mitogenic activities, and specifically activated the CD4(-)CD8(-) subset of lymphocytes.
  • T Satoh, T Hatakeyama, S Umeda, K Yokota, T Kakuchi
    POLYMER JOURNAL 28 6 520 - 526 1996年 [査読無し][通常論文]
     
    The cyclopolymerization of 1,2:5,5-dianhydro-3,4-di-O-methyl-D-glucitol was carried out using cationic and anionic catalysts. The polymerizations proceeded homogeneously up to high conversion and gave linear polymers without formation of gel. For the cationic cyclopolymerizations using BF3 . OEt(2) and SnCl4, the resulting polymer was confirmed to have the constitutional unit mainly of 2,5-anhydro-3,4-di-O-methyl-D-mannitol by comparing its C-13 NMR spectrum with that of 2,5-anhydro-1,3,4-6-tetra-O-methyl-D-mannitol. For anionic cyclopolymerization using t-BuOK, the obtained polymer consisted of two cyclic repeating units, 2.5-anhydro-3,4-di-O-methyl-D-mannitol and 2,5-anhydro-3,4-di-O-methyl-L-iditol. For the regio-and stereoselective polymerizations, intra- and intemolecular reactions introduced alpha- and beta-scissions of the epoxides with inversion and retention of the configuration at the alpha-carbon, respectively.
  • T Kakuchi, T Satoh, J Mata, S Umeda, H Hashimoto, K Yokota
    JOURNAL OF MACROMOLECULAR SCIENCE-PURE AND APPLIED CHEMISTRY A33 3 325 - 336 1996年 [査読有り][通常論文]
     
    The cyclopolymerizations of 1,2:5,6-dianhydro-3,4-di-O-pentyl-D-mannitol (1b) and 1,2:5,6-dianhydro-3,4-di-O-decyl-D-mannitol (1c) were carried out using BF3 . OEt(2) and t-BuOK. All the resulting polymers consisted of cyclic constitutional units, i.e., the extent of cyclization was 100%. The polymer structures for the polymerization with t-BuOK were (1 --> 6)-2,5-anhydro-3,4-di-O-pentyl-D-glucitol (2b) and (1 --> 6)-2,5-anhydro-3,4-di-O-decyl-D-glucitol (2c), whereas those with BF3 . OEt(2) comprised 2,5-anhydro-D-glucitols as major units along with other cyclic ones. These polymers were soluble in n-hexane, CHCl3, and THF, but insoluble in water, which differs from the amphiphilic solubility of (1 --> 6)-2,5-anhydro-3,4-di-O-methyl-D-glucitol (2a). The cation-binding properties of 2b and 2c were examined using alkali-metal picrates in order to compare them with those of 2a. The extraction yields for each cation decreased in the order of 2c < 2b < 2a. Every polymer exhibited a similar cation-binding selectivity in the order Cs+ > Rb+ > K+ much greater than Na+ > Li+. The ratio of K+ and Na+, K+/Na+, was 4.6 for 2a, 5.1 for 2b, and 7.1 for 2c in the increasing order 2a < 2b < 2c.
  • K YOKOTA, O HABA, T SATOH, T KAKUCHI
    MACROMOLECULAR CHEMISTRY AND PHYSICS 196 8 2383 - 2416 1995年08月 [査読有り][通常論文]
     
    This article presents several methods to prepare polymeric chiral crown ethers by cyclopolymerization. Chiral templates such as 1,1'-bi-2-naphthol, D-mannitol, L-threitol, and pyranosidic sugars are very useful for synthesizing the polymers by cyclopolymerization of divinyl ethers, polymers which possess the ability of chiral recognition towards or-amino acids. The chiral twist of the (R)- or (S)-binaphthyl template induces the main chain to form a chiral, R,R- or S,S-racemo sequence, respectively. Other templates with chiral axis can be also used as a tool for chirality induction in cyclopolymerization and cyclocopolymerization. The initiating system consisting of chiral alkylsulfonic acid and Lewis acid induces the enantioselective cyclopolymerization of a divinyl acetal (37). Chiral diepoxides polymerize regio- and stereospecifically with Lewis acid and KOH, and especially the diepoxide originating from D-mannitol forms a polymer having the character as a new macromolecular ionophore.
  • Toyoji Kakuchi, Toshifumi Satoh, Satoshi Umeda, Hisaho Hashimoto, Kazuaki Yokota
    Macromolecules 28 16 5643 - 5648 1995年07月01日 [査読無し][通常論文]
     
    The cyclopolymerizations of 1,2:5,6-dianhydro-3,4-di-O-methyl-D-mannitol (1) and -L-iditol (2) were carried out using BF3·OEt2 and SnCl4. The polymers obtained were soluble in chloroform, methanol, tetrahydrofuran, and water but insoluble in re-hexane. The specific rotations ([α]22546) of the polymers were +41.3 to +73.2° for 1 and +38.2 to +62.9° for 2 (c = 1.0, CHCl3). For all the polymers, the extent of cyclization was 100%. The structure of the polymers obtained from both 1 and 2 was (1→6)-bonded 2,5-anhydro-3,4-di-O-methyl-D-mannitol as the 5-membered constitutional unit, namely, poly-[(1→6)-2,5-anhydro-3,4-di-O-methyl-D-glucitol], The re-hexane-soluble products, which were obtained together with the n-hexane-insoluble polymers for the polymerization using BF3·OEt2, contained 1,6:2,5-dianhydro-3,4-di-O-methyl-D-glucitol, the cyclic dimer of 2,5-anhydro-3,4-di-O-methyl-D-glucitol and its higher cyclic homologs. © 1995, American Chemical Society. All rights reserved.
  • Toshifumi Satoh, Kazuaki Yokota, Toyoji Kakuchi
    Macromolecules 28 13 4762 - 4764 1995年06月01日 [査読無し][通常論文]
  • T KAKUCHI, T SATOH, S UMEDA, H HASHIMOTO, K YOKOTA
    MACROMOLECULES 28 12 4062 - 4066 1995年06月 [査読無し][通常論文]
     
    The cyclopolymerizations of 1,2:5,6-dianhydro-D-mannitols were carried out using cationic initiators. For the polymerization of 1,2:5,6-dianhydro-3,4-di-O-ethyl-D-manni with BF3 . OEt(2), the n-hexane-insoluble polymer consisted mainly of 2,5-anhydro-3,4-di-O-ethyl-D-glucitol as the cyclic constitutional unit and a large amount of 1,6:2,5-dianhydro-3,4-di-O-ethyl-D-glucitol was obtained as the n-hexane-soluble reaction product. The degree of polymerization for the n-hexane-insoluble polymer was 14-30, and the specific rotation ([alpha](22)(546)) was 42.7-54.3 degrees (c = 1.0 in CHCl3). On the other hand, 1,2: 5,6-dianhydro-3,4-O-isopropylidene-D-mannitol polymerized with BF3 . OEt(2-) and SnCl4-produced polymers with cyclic and acyclic units due to the restricted free rotation of the bond between the carbons at the 3,4-positions in which the extent of cyclization was about 0.5.
  • Synthesis of poly[(1->6)-2,5-anhydro-D-glucitol] by cationic cyclopolymerization of 3,4-di-O-allyl-1,2:5,6-dianhydro-D-mannitol
    Macromolecular Reports A32 7 1007 - 1018 1995年 [査読無し][通常論文]
  • T KAKUCHI, T SATOH, S UMEDA, J MATA, K YOKOTA
    CHIRALITY 7 3 136 - 139 1995年 [査読無し][通常論文]
     
    The chiral recognition property of poly[(1-->6)-2,5-anhydro-3,4-di-O-alkyl-D-glucitol] (1) toward racemic RCH (CO2CH3)NH3+. PF6- (2 . HPF6) has been studied using a transport system involving an aqueous source and receiving phases separated by a chloroform phase containing 1, Transport rates for aromatic guests 2a (R = Ph) and 2b (R = CH(2)Ph) were faster than those for aliphatic guests, 2c (R = CH(CH3)(2)) and 2d (R = CH2CH(CH3)(2)), using the polymer substituted with methyl groups (1a), The enantiomeric excess (e.e.) was 10.9% for 2a as a maximum value and decreased in the order of 2a > 2c > 2b = 2d, When the transport of 2a . HPF6 was carried out using the polymers with 3,4-di-O-methyl (1a), ethyl (1b), allyl (1c), and pentyl (1d) groups, the e.e. was 22.0% for 1d as a maximum value and increased in the order of 1a < 1b < 1c < 1d, The formation of a complex between 1a and 2a . HPF6 was confirmed by H-1 and C-13 NMR spectral measurements. (C) 1995 Wiley-Liss, Inc.
  • 村林 俊, 菊池 晃, 勇田 敏夫, 梅田 哲, 佐藤 敏文, 覚知 豊次
    人工臓器 23 S114a - S114a JAPANESE SOCIETY FOR ARTIFICIAL ORGANS 1994年
  • T KAKUCHI, Y HARADA, T SATOH, K YOKOTA, H HASHIMOTO
    POLYMER 35 1 204 - 206 1994年 [査読無し][通常論文]
     
    The chiral recognition property of poly[(1-->6)-2,5-anhydro-3,4-di-O-methyl-D-glucitol] (2b) towards racemic RCH(CO2CH3)NH3+.X(-) (3HX) has been studied using a transport system involving an aqueous source and receiving phases separated by a chloroform phase containing 2b. For HPF6, HClO4 and HCl salts of 3a (R=Ph), the amount of 3a transported into the receiving phase decreased in the order of PF6- > ClO4- > Cl-, but the optical purities changed only slightly from 9.3 to 10.9%. The transport rates for aromatic guests, 3a and 3b (R = CH(2)Ph), were faster than those for aliphatic ones, 3e (R = CH(CH3)(2)) and 3d (CH2CH(CH3)(2)), using PF6- as the counterion. The optical purity was 10.9% for 3a as a maximum value and decreased in the order of 3a > 3c> 3b and 3d. The formation of a complex between 2b and 3a HX was confirmed by H-1 and C-13 n.m.r. spectral measurements.
  • T KAKUCHI, H HASHIMOTO, Y HARADA, T SATOH, K YOKOTA
    JOURNAL OF MACROMOLECULAR SCIENCE-PURE AND APPLIED CHEMISTRY A31 6 751 - 759 1994年 [査読有り][通常論文]
     
    Cyclocopolymerizations of 5,6-benzo-1,2:9,10-diepoxy-4,7-dioxa-deca-5-ene (BDD) and monoepoxy comonomers, propylene oxide (PO), epichlorohydrin (ECH), and phenyl glycidyl ether (PGE), were carried out with SnCl4 to form gel-free copolymers with no residual epoxy groups. The copolymerization parameters were r1 = 1.09 and r2 = 0.86 for BDD (M1)-PGE (M2). In addition, 5,6:14,15-dibenzo-1,2:18,19-diepoxy-4,7,-10,13,16-pentaoxanonadeca-5,14-diene (DDP) with PO, ECH, or PGE were copolymerized with SnCl4 in CH2Cl2 and with KOH in DMSO to form copolymers with dibenzo-19-crown-6 units. Poly[(dibenzo-19-crown-6)-co-PO] and poly[(dibenzo-19-crown-6)-co-PGE] showed lower extracting yields for alkali-metal picrates than did the homopolymer of DDP, poly(dibenzo-19-crown-6). However, poly[(dibenzo-19-crown-6)-co-PGE] exhibited a higher selectivity for K+ than did the other polymers.

MISC

書籍等出版物

  • Complex Macromolecular Architectures: Synthesis, Characterization, and Self-Assembly
    John Wiley & Sons (Asia) Pte Ltd, Singapore 2011年
  • Ionic Liquid Applications: Pharmaceuticals, Therapeutics, and Biotechnology, ACS Symposium Series, 1038 (Ionic Liquid Applications)
    American Chemical Society 2010年
  • イオン液体III―ナノ・バイオサイエンスへの挑戦― Ionic Liquid III―Challenges to Nano-Bio Sciences―
    (株)シーエムシー出版 2010年
  • Current Topics in Polymer Research
    Nova Science Publishers, Inc. 2005年
  • Advances in Controlled/Living Radical Polymerization
    American Chemical Society 2003年
  • Polymeric Material Encyclopedia
    CRC Press 1996年

講演・口頭発表等

担当経験のある科目(授業)

  • 高分子機能化学北海道大学
  • 高分子化学北海道大学

所属学協会

  • 有機合成化学協会   日本化学会   基礎錯体工学研究会   高分子学会北海道支部 若手研究会   米国化学会   高分子学会   The Chemical Society of Japan   American Chemical Society   Japan.   The Society of Polymer Science   

Works(作品等)

  • 第4回北大セミナー in 函館
    2007年

共同研究・競争的資金等の研究課題

  • 超精密・超微細ナノ加工を指向した単分散ブロックポリマーの創製
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2020年04月 -2023年03月 
    代表者 : 磯野 拓也, 佐藤 敏文
  • ハイブリッド触媒を用いた配列規制重合法と連続制御重合法の構築
    日本学術振興会:科学研究費助成事業 新学術領域研究(研究領域提案型)
    研究期間 : 2020年04月 -2022年03月 
    代表者 : 佐藤 敏文
  • 環状混合ソフトマテリアルの絡み合い制御による超ゴム弾性発現の分子論的解明
    日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 陣内 浩司, 佐藤 敏文, 萩田 克美
  • 超高アスペクト比ナノセルロースのネットワーク構造を活用した抗がん剤の効率的な送達
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 田島 健次, 安藤 英紀, 石田 竜弘, 甲野 裕之, 磯野 拓也, 佐藤 敏文, 藤田 彩華
  • シングルナノサイズのミクロ相分離構造を実現するブロック共重合体デザイン
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 佐藤 敏文, 山本 拓矢, 磯野 拓也
  • 日本学術振興会:科学研究費助成事業 挑戦的研究(萌芽)
    研究期間 : 2019年06月 -2021年03月 
    代表者 : 佐藤 敏文, 山本 拓矢, 磯野 拓也
  • ハイブリッド触媒を用いた配列規制重合法の創成
    日本学術振興会:科学研究費助成事業 新学術領域研究(研究領域提案型)
    研究期間 : 2018年04月 -2020年03月 
    代表者 : 佐藤 敏文
     
    本研究はハイブリッド触媒を用いた配列規制重合の開発とこの重合法を利用した高付加価値な機能性高分子材料の開発を目的としている。本年度は下記の2つについて重点的に検討を行った。 ①新規ハイブリッド触媒の探索:新たなハイブリッド触媒系として酸・塩基複合型触媒に着目し、触媒候補の探索を行った。その結果、安息香酸アルカリ金属塩がラクチドや環状カーボネートの開環において有用であることを見出した。安息香酸部位のベンゼン環上置換基を変えた一連の触媒を用いて重合を行い、触媒回転頻度を調べた。その結果、安息香酸アルカリ金属塩の塩基性が高くなるほど触媒回転頻度が高くなる傾向が確認された。このことから、本重合はアニオン重合性の機構で進行していることが示唆された。また、分子内で酸・塩基複合しているベタインに着目し、その重合触媒としての可能性を検討した。その結果、トリメチルグリシンが環状カーボネートの開環重合に有用であることを見出した。トリメチルグリシンはモノマーのカルボニル基と生長末端水酸基の両方を活性化することがIR測定により判明し、重合は二重活性化機構で進行していることが示唆された。 ②ハイブリッド触媒を用いた配列規制重合:グリコール酸と乳酸の共重合体であるPLGAは生体適合性と生体内分解性を兼ね備えており、医療用材料として極めて重要である。PLGA中のグリコール酸と乳酸ユニットは多くの場合ランダムに配列しているが、本研究ではハイブリッド触媒を用いることでメチルグリコリドの開裂位置選択的開環重合を実現し、配列制御によるPLGAの物性制御を目指した。幾つかの触媒を検討したところ、ホスファゼン塩基/アルコール触媒系を用いることで交互性の高い配列を有するPLGAが得られることを見出した。
  • 配列制御機構を利用した高粘弾性ポリマーの微生物生産
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2017年04月 -2020年03月 
    代表者 : 松本 謙一郎, 大井 俊彦, 佐藤 敏文
     
    微生物産生ポリエステル(PHA)は、糖や脂質などの様々なバイオマスから合成可能であり、プラスチック材料として利用できる高分子である。加えて、海洋分解性を有する数少ないプラスチックの一つであり、近年の海洋のプラスチック汚染に対する関心の高まりを受けて、注目されている。PHAはすでに産業利用されている材料であるが、さらなる用途拡大のためには、物性の拡張が必要とされていた。ポリマー材料の構造と物性は、モノマーユニットの構造およびそれらが重合される際のモノマー配列によって大きく影響される。二種類のポリマーを貼り合わせた構造を有するブロック共重合体は、2つのポリマーの物性を併せ持つ有用な物性を示すことから、合成高分子分野で盛んに合成されている。一方、PHAをブロック化させることは困難であり、これまで成功例はなかった。 研究代表者の研究グループでは、特殊なPHA合成系を構築することにより、ブロック配列を有するPHAの生合成に初めて成功した。本手法では、二種類以上のモノマー前駆体の混合物を組換え大腸菌の培地に添加してポリマー合成を行う。すると、大腸菌内で自発的にある特定の配列でポリマーが重合されブロック共重合体が合成される。本研究課題では、この特異なポリマー合成系に対し、合成機構の解明と材料生産への応用の2つの側面から取り組んだ。 合成機構の解明では、モノマーが重合される速度を知るために、インビトロ系による酵素活性測定を実施した。研究代表者は、PHAの共重合の解析方法を初めて構築した。本手法を用いて、これまでに複数のポリマー合成系について酵素活性測定を行い、興味深い結果を得ることができた。加えて、ポリマーをフィルムに加工して、熱的・機械的性質の測定も行った。ブロック配列を有しない従来型のPHAとは異なる物性を示すことを確認できた。
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2016年04月 -2019年03月 
    代表者 : 佐藤 敏文, 山本 拓矢, 磯野 拓也
     
    本研究は、次世代リソグラフィーへの応用に向けたブロック共重合体(BCP)の新規設計指針の確立を目指すものである。 各種の精密リビング重合やクリック反応を駆使することで、分岐状あるいは環状構造を有する両親媒性BCPならびに立体規則性を制御した両親媒性BCPを合成した。ミクロ相分離構造の解析結果より、ブロック共重合体への非直鎖状構造の導入は重合度に依存せずにミクロ相分離構造の周期間隔を微細化する有用な手段となることを明らかにした。また、ブロック共重合体の立体規則性の制御はより高度に配列したモルフォロジーを構築する方法論となり得ることも見出した。
  • 日本学術振興会:科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2016年04月 -2018年03月 
    代表者 : 佐藤 敏文, 山本 拓矢, 磯野 拓也
     
    本研究では、多環状高分子の新たな合成法として「連鎖的環形成」を確立した。すなわち、両末端に重合性官能基を備えた直鎖状高分子を前駆体とし、その重合性基を介して次々に環状ユニットを形成するものである。具体的には、両末端にノルボルネニル基を有する直鎖状ポリマーを環化重合することで連鎖的環形成を実現し、環サイズおよび環状ユニット数を制御した多環状高分子の合成に成功した。さらに、本手法により合成したサンプルを用いて多環状高分子の系統的な物性評価も行った。
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 松本 謙一郎, 大井 俊彦, 田口 精一, 佐藤 敏文
     
    再生可能なバイオマスから合成可能な微生物産生ポリエステルの有効活用のためには、優れた材料物性を発揮させることが重要な課題となる。通常、微生物合成を用いるとランダム共重合体が合成されるが、我々はランダム性が低いポリマーが得られる条件を偶然見出した。本研究課題では、この発見を端緒に、新規なポリマー合成系の確立を目指した。モノマー配列の一次構造を解析するとともに、機械的・熱的物性を測定した。さらに、酵素を細胞から単離精製して生化学的な解析を行い、関連する酵素の活性を評価した。これら一連の実験結果に基づいて、対象としたポリエステル合成系について、合成から物性に至るまで幅広い情報を得ることができた。