研究者業績
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  2. 青木 大輔

青木 大輔

アオキ ダイスケ  (Daisuke Aoki)

基本情報

所属
千葉大学 大学院工学研究院 准教授
学位
博士（工学）(東京工業大学)
ORCID ID
 https://orcid.org/0000-0002-7272-0643
J-GLOBAL ID
201801020964389097
researchmap会員ID
B000300505

研究分野

 1

論文

 119
  • Takumi Yamamoto, Sota Kato, Daisuke Aoki, Hideyuki Otsuka
    Angewandte Chemie - International Edition 60(5) 2680-2683 2021年2月1日  
    Since the beginning of polymer science, understanding the influence of mechanical stress on polymer chains has been a fundamental and important research topic. The detection of mechanoradicals generated by homolytic cleavage of the polymer chains in solution has been studied in many cases. However, the detection of mechanoradicals in the bulk is still limited owing to their high reactivity. Herein, we propose an innovative strategy to detect mechanoradicals visually and quantitatively using a chain-transfer agent that generates relatively stable fluorescent radicals as a molecular probe. Mechanoradicals generated by ball milling of polystyrene samples were successfully detected by using a diarylacetonitrile compound as a fluorescent molecular probe through this radical chain-transfer mechanism. This probe enables the visualization and quantitative evaluation of mechanoradicals generated by polymer-chain scission.
  • Takumi Yamamoto, Sota Kato, Daisuke Aoki, Hideyuki Otsuka
    Angewandte Chemie 133(5) 2712-2715 2021年2月  
  • Kuniaki Ishizuki, Daisuke Aoki, Hideyuki Otsuka
    Macromolecular Rapid Communications 42(1) 2021年1月1日  
    Mechanochromic polymers can be used as stress- and damage-detecting sensors in polymeric materials, given that mechanical stimuli can be visualized by color changes. Although many types of mechanochromic polymers have been reported so far, there are only few examples on their further functionalization based on multiple color changes (multicolor mechanochromism). Herein, preliminary results are reported on the use of multicolor mechanochromism to detect the duration of the mechanical stimulation by simply mixing white powders of two mechanochromic polystyrene samples that contain a different radical-type mechanochromophore at the midpoint of each polymer chain and thus exhibit different colors in response to mechanical stimuli. The mechanosensitivity can be tuned via the polymer length and shape, and a combination of these two types of mechanochromic polymers allows detecting the duration with multicolor mechanochromism, i.e., a color change from white to blue upon short exposure to grinding and a color change from white to gray upon longer exposure to grinding. Electron paramagnetic resonance and solid-state UV–vis measurements support the mechanism proposed for this multiple mechanochromism.
  • Daisuke Aoki, Gota Aibara, Toshikazu Takata
    Polymer Chemistry 2021年  
  • Yuki Tsukamoto, Jumpei Kida, Daisuke Aoki, Hideyuki Otsuka
    Polymer Chemistry 2021年  
  • Takumi Abe, Rikito Takashima, Takehiro Kamiya, Choon Pin Foong, Keiji Numata, Daisuke Aoki, Hideyuki Otsuka
    Green Chemistry 23(22) 9030-9037 2021年  
    A polymer is used as a source of fertilizer. To demonstrate the viability of this concept, the chemical recycling of poly(isosorbide carbonate) (PIC) is presented as a model for the next generation of plastic-recycling systems.
  • Kosaku Yanada, Sota Kato, Daisuke Aoki, Koichiro Mikami, Hajime Sugita, Hideyuki Otsuka
    Chemical Communications 57(23) 2899-2902 2021年  
    A non-symmetric radical-type mechanophore (CF/ABF) was synthesized by molecular crossing between two radical-type mechanophores. The thermal stability and mechanoresponsiveness of CF/ABF were found to be tunable by altering the properties of the parent RMs. The CF/ABF-centred polymers showed mixed mechanochromism derived from the simultaneous generation of two radical species.
  • Yuchen Mao, Yuto Kubota, Takashi Kurose, Akira Ishigami, Kota Seshimo, Daisuke Aoki, Hideyuki Otsuka, Hiroshi Ito
    Macromolecules 53(21) 9313-9324 2020年11月10日  
    A rigid and brittle cross-linking structure was introduced into the flexible poly(n-hexyl methacrylate) (PHMA) network by the mechanochromic cross-linker difluorenylsuccinonitrile-containing methacrylate (DFMA), whose central C-C bond acted as a dynamic covalent bond and could generate pink radicals when fractured. PHMA with DFMA showed a remarkable hysteresis loop and mechanical enhancement. After deformation, the reassociation of dynamic covalent bonds and the reorganization of the network structure slowed down the recovery of the polymer to its initial state. The correlations between tension stimulation, energy dissipation, and mechanoresponsive color change were discussed. Under stress, the polymer changed from light gray to pink. The broad distribution of red channel intensity under large deformation detected on the surface confirmed that the rupture of dynamic covalent bonds occurred evenly throughout the polymer and suppressed stress concentration. The color showed a strong dependence on stress, which started to appear at around 1.5 to 2.0 MPa. The incorporation of DFMA promised mechanical enhancement and noncontact stress detection ability of the PHMA soft material.
  • Hio Sakai, Daisuke Aoki, Kota Seshimo, Koichi Mayumi, Shotaro Nishitsuji, Takashi Kurose, Hiroshi Ito, Hideyuki Otsuka
    ACS Macro Letters 9(8) 1108-1113 2020年8月18日  
    A difluorenylsuccinonitrile-(DFSN)-based linker, whose central C-C bond is readily cleaved under mechanical stress to generate a relatively stable pink radical species, was introduced into polymer networks. DFSN-based cross-linked polymers exhibit improved mechanical properties as compared to those of the corresponding covalently cross-linked polymers owing to the energy dissipation induced by cleavage of the central DFSN bond. The toughening mechanism of DFSN-based elastomers is qualitatively visualized by the intensity of the pink color and can be quantitatively characterized by electron paramagnetic resonance. These results demonstrate that the extent of DFSN cleavage is the main factor improving the mechanical properties of the polymer networks.
  • Yasuhiro Shoda, Daisuke Aoki, Katsuhiko Tsunoda, Hideyuki Otsuka
    Polymer 202 2020年8月12日  
    In the context of pneumatic tires, high durability and fuel efficiency reside in a trade-off relationship. This problem may be solved by the introduction of hydrogen bonds into cured rubber, as elastic materials with hydrogen bonds exhibit a different strain dependence of their energy dissipation compared to elastic materials with conventional chemical bonds. Herein, we have applied cross-metathesis reactions between polybutadienes and olefin-containing polyurethanes to the synthesis of novel polybutadienes with urethane linkages as a source of hydrogen bonds in the polymer main chain (PBUs). A series of PBUs with different contents of urethane linkages was synthesized by changing the feed ratios of the polybutadiene and olefin-containing polyurethanes in cross-metathesis reactions, and the resulting PBUs were characterized in order to examine the effect of the hydrogen bonds on the macroscopic mechanical properties. Cured rubber materials prepared from PBUs exhibit higher tearing energy and energy dissipation at high strains compared to conventional control rubber samples, and the tearing energy related to energy dissipation at high strains improves with increasing urethane content. Therefore, the present approach represents a powerful strategy for conciliating durability and fuel efficiency in cured rubbers.
  • Rikito Takashima, Daisuke Aoki, Hideyuki Otsuka
    Macromolecules 53(12) 4670-4677 2020年6月23日  
  • Takuma Kureha, Seina Hiroshige, Daisuke Suzuki, Jun Sawada, Daisuke Aoki, Toshikazu Takata, Mitsuhiro Shibayama
    Langmuir 36(18) 4855-4862 2020年5月12日  査読有り
  • Jun Sawada, Daisuke Aoki, Yilin Sun, Ken Nakajima, Toshikazu Takata
    ACS Applied Polymer Materials 2020年3月13日  
  • Ayuko Tsuruoka, Akira Takahashi, Daisuke Aoki, Hideyuki Otsuka
    Angewandte Chemie 132(11) 4620-4620 2020年3月9日  
  • Ayuko Tsuruoka, Akira Takahashi, Daisuke Aoki, Hideyuki Otsuka
    Angewandte Chemie 132(11) 4324-4328 2020年3月9日  
  • Ayuko Tsuruoka, Akira Takahashi, Daisuke Aoki, Hideyuki Otsuka
    Angewandte Chemie International Edition 59(11) 4590-4590 2020年3月9日  
  • Nao Tsurumi, Rikito Takashima, Daisuke Aoki, Shigeki Kuwata, Hideyuki Otsuka
    Angewandte Chemie 132(11) 4299-4303 2020年3月9日  
  • Nao Tsurumi, Rikito Takashima, Daisuke Aoki, Shigeki Kuwata, Hideyuki Otsuka
    Angewandte Chemie International Edition 59(11) 4269-4273 2020年3月9日  
    A simple and efficient method to generate macrocyclic structures has been developed based on the dynamic behavior of the linker bis(2,2,6,6-tetramethylpiperidin-1-yl)disulfide (BiTEMPS). The prime linear structure was transformed into a (macro)cycle using the following sequence: 1) thiol-ene reaction with a BiTEMPS derivative to afford the linear precursor, then 2) an entropy-driven transformation induced by diluting and heating. The radicals generated from BiTEMPS upon heating are highly tolerant toward a variety of chemical species, including oxygen and olefins, but they exhibit high reactivity in exchange reactions, which can be applied to the topology transformation of various skeletons. The advantages of the present method, namely, its procedural simplicity and substrate versatility, are demonstrated by the gram-scale synthesis of cyclic compounds with low and relatively high molecular weight.
  • Ayuko Tsuruoka, Akira Takahashi, Daisuke Aoki, Hideyuki Otsuka
    Angewandte Chemie International Edition 59(11) 4294-4298 2020年3月9日  
  • Kazuma Kawasaki, Daisuke Aoki, Hideyuki Otsuka
    Macromolecular Rapid Communications 1900460-1900460 2020年1月8日  査読有り
  • Rikito Takashima, Masashi Ohira, Hirogi Yokochi, Daisuke Aoki, Xiang Li, Hideyuki Otsuka
    Soft Matter 16(48) 10869-10875 2020年  
    <p>Characterization of <italic>N</italic>-phenylmaleimide-terminated poly(ethylene glycol)s and their application to a tetra-arm poly(ethylene glycol) gels</p>
  • Daisuke Aoki, Moeko Yanagisawa, Hideyuki Otsuka
    Polymer Chemistry 2020年  
  • Hirogi Yokochi, Rikito Takashima, Daisuke Aoki, Hideyuki Otsuka
    Polymer Chemistry 2020年  
  • Yumiko Ito, Daisuke Aoki, Hideyuki Otsuka
    Polymer Chemistry 2020年  
  • Yi Lu, Daisuke Aoki, Jun Sawada, Takahiro Kosuge, Hiromitsu Sogawa, Hideyuki Otsuka, Toshikazu Takata
    Chemical Communications 2020年  査読有り
  • Rikito Takashima, Jumpei Kida, Daisuke Aoki, Hideyuki Otsuka
    Journal of Polymer Science Part A: Polymer Chemistry 57(24) 2396-2406 2019年12月15日  
  • Daisuke Aoki, Hideyuki Otsuka
    Mechanically Responsive Materials for Soft Robotics 307-325 2019年11月19日  
    Mechanochromic materials that consist of polymer chains are expected to be good candidates for stress-sensing because their mechanical properties can be readily tuned by a judicious choice of the appropriate polymer composition. In this chapter, an approach for the development of functional polymers with mechanochromic properties and their characteristics are summarized with a focus on the dynamic covalent chemistry.
  • Brian J. Ree, Daisuke Aoki, Jehan Kim, Toshifumi Satoh, Toshikazu Takata, Moonhor Ree
    MACROMOLECULAR RAPID COMMUNICATIONS 40(21) 2019年11月  
    In this study, poly(delta-valerolactone) (PVL) axles bearing movable and fixed dibenzo-24-crown-8-ether wheels (rot-M and rot-F) are investigated for the first time in the terms of phase transition and nanoscale film morphology: PVL-rot-M and PVL-rot-F. Interestingly, the PVL axles reveal a strong tendency to form a horizontal lamellar structure with three different rotational crystal lattice domains in nanoscale films. The morphological structural parameters are discernibly varied by the movable and fixed rotaxane wheels. In particular, the rot-M wheel tends to be populated in both the interfacial and amorphous layers. The rot-M wheel is found to significantly influence the phase transition characteristics of the PVL axle because of its movability along the polymer backbone chain. In contrast, the rot-F wheel tends to be more localized in the interfacial layer rather than in the amorphous layer because of its immovability constrained at the polymer chain end. The rot-F wheel causes severe thermal instability in the PVL axle, which can be attributed mainly to the presence of its counter anion (PF6-).
  • Takahiro Kosuge, Daisuke Aoki, Hideyuki Otsuka
    Polymer 177 10 2019年8月  査読有り
  • Brian J. Ree, Daisuke Aoki, Jehan Kim, Toshifumi Satoh, Toshikazu Takata, Moonhor Ree
    Macromolecules 52(14) 5325-5336 2019年7月23日  査読有り
    In this study, poly(delta-valerolactone) (PVL) axles bearing movable and ionically fixed rotaxane wheels linked with polystyrene (rot-PS-M and rot-PS-F) have been investigated for the first time in the aspects of nanoscale film morphology by using synchrotron grazing incidence X-ray scattering: PVL-rot-PS-M and PVL-rot-PS-F. In addition, their thermal stabilities and phase-transition behaviors have been examined. PVL-rot-PS-M reveals a higher thermal stability than that of PVL-rot-PS-F, having an ionic character and a counter anion. The quantitative analyses of this study found that the mechanically linked rotaxane wheel could be able to enhance significantly the mobilities of the PVL axle and the PS block, which are essential for their phase separation and the PVL axle crystallization. With higher chain mobilities due to the movable rotaxane wheel, PVL-rot-PS-M always reveals a much better performance in the formation of the phase-separated PVL/PS lamellar structure as well as in the crystallization of the PVL axle chain, compared to PVL-rot-PS-F and the counter diblock copolymer. All morphology details as well as thermal stability and phase transition details are discussed, considering the nature of movable, ionically fixed, and covalent-bonded linkers between PVL and PS blocks.
  • Jun Sawada, Daisuke Aoki, Hiromitsu Sogawa, Ken Nakajima, Toshikazu Takata
    MACROMOLECULAR SYMPOSIA 385(1) 2019年6月  査読有り
    Rotaxane-cross-linked polymers (RCP), which have rotaxane structures at the cross-link points, show unique physical properties originating from the movable cross-link points. Herein, poly(N,N-dimethylacrylamide) (PDMAAm) and poly(N-isopropylacrylamide) (PNIPAm) which are well known as hydrophilic polymers and whose glass transition temperatures are much higher than room temperature, were applied as matrix polymers for RCPs. These RCPs are easily and successfully synthesized by radical polymerization of vinyl monomers in the presence of small amounts of [2]rotaxane cross-linker (RC) comprising one wheel and one axle component with a methacrylate group on each component. As the result, PDMAAm-based RCP without any solvents and PNIPAm-based RCP swelled with water were much tougher than corresponding covalently cross-linked polymers. It is confirmed that RC endows both of the hard polymer networks and soft hydrogels with toughness.
  • Jun Sawada, Daisuke Aoki, Hideyuki Otsuka, Toshikazu Takata
    Angewandte Chemie - International Edition 58(9) 2765-2768 2019年2月25日  
    Three component mobility controlling vinylic rotaxane crosslinkers with two radically polymerizable vinyl groups (RC_Rs) were synthesized to prove that the mobility of the components of the RC_Rs plays a crucial role in determining the properties of rotaxane-crosslinked polymers (RCPs). RC_Rs (R=H, Me, or Et) were obtained from living ring-opening polymerization. RCP_Et was prepared using RC_Et, which exhibits the lowest component mobility. The low component mobility is reflected in inferior mechanical strength and stretching ability in tensile stress tests compared to components with good (R=Me) and high (R=H) mobility. However, RCP_Et exhibited significantly higher stress and strain values than the corresponding covalently crosslinked polymers (CCP_Rs). These results indicate that a suitable component mobility substantially enhances the mechanical strength of RCPs. This behavior could serve as a guiding principle for the molecular design of advanced RCs.
  • Takahiro Kosuge, Xiaolei Zhu, Vivian M. Lau, Daisuke Aoki, Todd J. Martinez, Jeffrey S. Moore, Hideyuki Otsuka
    Journal of the American Chemical Society 2019年2月  査読有り
  • Kazuhiko Yamada, Daisuke Aoki, Kazuko Nakazono, Toshikazu Takata
    Zeitschrift fur Naturforschung B 74(5) 421-425 2019年  査読有り
  • 広重聖奈, 澤田隼, 青木大輔, 高田十志和, 鈴木大介
    日本レオロジー学会誌 47(2) 51-54 2019年  査読有り招待有り
  • Fumika Hoshino, Takahiro Kosuge, Daisuke Aoki, Hideyuki Otsuka
    Materials Chemistry Frontiers 2019年  査読有り
  • Takuma Watabe, Kuniaki Ishizuki, Daisuke Aoki, Hideyuki Otsuka
    Chemical Communications 2019年  査読有り
  • Sota Kato, Daisuke Aoki, Hideyuki Otsuka
    Polymer Chemistry 2019年  査読有り
  • Jumpei Kida, Daisuke Aoki, Hideyuki Otsuka
    ACS Macro Letters 1 2019年1月  査読有り
  • Jumpei Kida, Keiichi Imato, Raita Goseki, Daisuke Aoki, Masakazu Morimoto, Hideyuki Otsuka
    Nature Communications 9(1) 2018年12月  査読有り
  • Hio Sakai, Toshikazu Sumi, Daisuke Aoki, Raita Goseki, Hideyuki Otsuka
    ACS Macro Letters 1359 2018年11月  査読有り
  • Sota Kato, Kuniaki Ishizuki, Daisuke Aoki, Raita Goseki, Hideyuki Otsuka
    ACS Macro Letters 1087 2018年9月  査読有り
  • Hiroki Sato, Daisuke Aoki, Toshikazu Takata
    Chemistry - An Asian Journal 13(7) 785-789 2018年4月4日  査読有り
    We developed novel size-complementary molecular and macromolecular rotaxanes using a 2,6-dimethylphenyl terminal group as the axle-end-cap group in dibenzo-24-crown-8-ether (DB24C8)-based rotaxanes, where the 2,6-dimethylphenyl group was found to be less bulky than the 3,5-dimethylphenyl group. A series of molecular and macromolecular [2]rotaxanes that bear a 2,6-dimethylphenyl group as the axle-end-cap were synthesized using unsubstituted and fluorine-substituted DB24C8. Base-induced decomposition into their constituent components confirmed the occurrence of deslipping, which supports the size-complementarity of these rotaxanes. The deslipping rate was independent of the axle length but dependent on the DB24C8 substituents. A kinetic study indicated the rate-determining step was that in which the wheel is getting over the end-cap group, and deslipping proceeded via a hopping-over mechanism. Finally, the present deslipping behavior was applied to a stimulus-degradable polymer as an example for the versatile utility of this concept in the context of stimulus-responsive materials.
  • Yumiko Ito, Jumpei Kida, Daisuke Aoki, Hideyuki Otsuka
    Chemical Communications 2018年  査読有り
  • Takata T, Aoki D
    Polymer Journal 50(1) 127-147 2018年  査読有り
  • Ishizuki, K., Aoki, D., Goseki, R., Otsuka, H.
    ACS Macro Letters 7(5) 556-560 2018年  査読有り
    Mechanochromic polymers, which react to mechanical force by changing color, are expected to find applications in smart materials such as damage sensors. Although numerous types of mechanochromic polymers have been reported so far, developing mechanochromic polymers that can recognize different mechanical stimuli remains a formidable challenge. Materials that not only change their color in response to a mechanical stimulus but also detect its nature should be of great importance for practical applications. In this paper, we report our preliminary findings on multicolor mechanochromic polymer blends that can discriminate between two different mechanical stimuli, i.e., stretching and grinding, by simply blending two mechanochromic polymers with different architectures. The rational design and blending of two mechanochromic polymers with radical-type mechanochromophores embedded separately in positions adjacent to soft or hard domains made it possible to achieve multicolor mechanochromism in response to different stimuli. Electron paramagnetic resonance and solid-state UV-vis measurements supported the mechanism proposed for this discrimination.
  • Ishizuki, K., Oka, H., Aoki, D., Goseki, R., Otsuka, H.
    Chemistry - A European Journal 24(13) 3170-3173 2018年  査読有り
    Mechanochromic polymers, that is, polymers sensitive to mechanical impact, promise great potential for applications in damage sensors. In particular, radical-type mechanochromic polymers, which produce colored radical species in response to mechanical stress, may enable not only the visualization of mechanical stress, but also its quantitative evaluation by electron paramagnetic resonance analysis. Herein, a radical-type mechanochromic polymer that exhibits a color change from white to green upon dissociation of a diarylbibenzothiophenonyl moiety at the mid-point of a polystyrene chain is presented, and its mechanochromic behavior is examined. Mechanochromic materials that show a variety of colors (“rainbow colors”) in response to mechanical stress were prepared by simply mixing radical-type mechanochromic polymers of primary colors.
  • Ogawa, M., Sogawa, H., Mizuno, S., Aoki, D., Takata, T.
    ChemistrySelect 3(2) 446-450 2018年  査読有り
    Palladium-complexing macrocyclic catalysts efficiently and chemoselectively catalysed the Suzuki coupling reaction of bromoarenes. Bromobenzene and 2-bromopyridine were efficiently monoarylated with 4-methoxyphenylboronic acid when catalysed by macrocyclic catalysts comprising cyclic pyridine-2,6-bisamide pincer-type ligands with palladium (II) located in the inner cavity (PdMCs). The Suzuki coupling of 2,6-dibromopyridine to aryl boronic acids catalysed by PdMCs afforded the corresponding monoarylpyridines with high selectivity and yield, whereas a mixture of mono- and di-arylpyridines was obtained when palladium chloride was used as the catalyst. Interestingly, the chemoselectivity increased as the cavity size of the PdMCs decreased. The high chemoselectivity seemed to arise from the steric effect of the macrocyclic ligand. Moreover, an unsymmetrical 2,6-diarylpyridine was successfully synthesised in high yield by two sequential couplings employing PdMCs followed by palladium chloride.
  • Daisuke Aoki, Toshikazu Takata
    Polymer 128 276-296 2017年10月  査読有り
    This review article deals with the construction and function of dynamic macromolecular systems having mechanically linked polymer chains which can undertake a topology transformation to induce structure and property changes. Synthesis of a macromolecular [2] rotaxane (M2R) possessing a macromolecular switch function is first described, which is a structure-definite ideal polyrotaxane consisting of one polymer axle and one macrocycle wheel. Its application to the synthesis of rotaxane cross-linked polymers (RCP) and topology-transformable polymers is discussed along with their properties, where the rotaxane-linking of polymer chains plays a crucial role. The M2R-based cross-linker is prepared and applied to the synthesis of RCPs by adding it into radical polymerization systems of vinyl monomers. RCPs have high stretchability and toughness. Rotaxane-linked block copolymers and cyclic polymers synthesized by introducing polymer chains onto the wheel and axle components of M2R are subjected to the topology transformation using the switch function of M2R to cause remarkable structure and property changes. (C) 2017 Elsevier Ltd. All rights reserved.
  • Seina Hiroshige, Takuma Kureha, Daichi Aoki, Jun Sawada, Daisuke Aoki, Toshikazu Takata, Daisuke Suzuki
    Chemistry - A European Journal 23(35) 8405-8408 2017年6月5日  査読有り
    Compared to rigid microspheres that consist, for example, of polystyrene or silica, soft and deformable elastomer microspheres can be used to generate colorless transparent films upon evaporating the solvent from microsphere-containing dispersions. To obtain tough films, a post-polymerization reaction to crosslink the microspheres is usually necessary, which requires extra additives during the drying process. This restriction renders this film-formation technology complex and rather unsuitable for applications in which impurities are undesirable. In the present study, it is demonstrated that tough elastomer microspheres that are crosslinked with rotaxanes can form tough bulk films upon evaporation of water from microsphere dispersions, so that post-polymerization reactions are not required. The results of this study should thus lead to new applications including coatings for biomaterials that need complete removal of all impurities from the materials prior to use.

MISC

 16
  • 鈴木大介, 高田十志和, 青木大輔
    『動的秩序と機能』ニュースレター 51 1 2017年11月  
  • 鈴木大介, 高田十志和, 青木大輔
    『動的秩序と機能』ニュースレター 46 3 2017年6月  
  • 高田 十志和, 青木 大輔
    高分子 = High polymers, Japan : polymers 66(5) 217-219 2017年5月  
  • 水野舜也, 曽川洋光, 青木大輔, 山本浩司, 高田十志和
    日本化学会春季年会講演予稿集(CD-ROM) 97th 2017年  
  • 青木 大輔, 高田 十志和
    日本ゴム協会誌 90(6) 283-289 2017年  
    &lt;p&gt;This review summarizes the development of stimuli-responsive materials based on the topology transformable polymers from branched to linear. The junction point of the rotaxane components bearing plural polymer chains is the key for the topology transformation which cannot be attained by the fixed junction point formed by the covalent bond. Crown ether-containing macromolecular [2]rotaxane with both ammonium and urethane moieties (M2R) as the stations for the crown ether wheel on the axle polymer chain produces the controllable and movable junction point of the polymer chains via the control of the component interaction, which enables the construction of sophisticated dynamic polymer systems. The rotaxane-linked star polymers with a fixed rotaxane linkage owing to the ammonium/crown ether interaction were synthesized by the introduction of two additional polymer chains to the components of M2R. The star polymers altered their topology to linear by the &lt;i&gt;N&lt;/i&gt;-acetylation of the ammonium moiety, which broke the ammonium/crown ether interaction and generated the urethane/crown ether interaction to move the wheel component to the polymer chain terminal, eventually affording the linear polymer. The change in physical property caused by the topology transformation was confirmed in hydrodynamic volume and viscosity, demonstrating an effective way to the development of novel stimuli-responsive materials.&lt;/p&gt;
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