Spontaneous deformation of main-chain liquid-crystalline elastomers composed of smectic polyesters |
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| Authors: | Kazuyuki Hiraoka Tohru Tashiro Masatoshi Tokita Junji Watanabe |
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| Affiliation: | 1. Center for Nano Science and Technology, Department of Nanochemistry , Tokyo Polytechnic University , 1583 Iiyama, Atsugi-shi, 243-0297, Japan hiraoka@nano.t-kougei.ac.jp;3. Center for Nano Science and Technology, Department of Nanochemistry , Tokyo Polytechnic University , 1583 Iiyama, Atsugi-shi, 243-0297, Japan;4. Department of Organic and Polymeric Materials , Tokyo Institute of Technology , O-okayama, Mrguro-ku, Tokyo, 152-8552, Japan |
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| Abstract: | ![]()
We observe the spontaneous shape change of a uniaxially deformed liquid-crystalline elastomer composed of smectic main-chain liquid-crystalline polyesters in a cyclic heating–cooling process. Although the elastomer contracts by about 115% on heating up to the isotropic phase, the sample length recovers by 55% on cooling to room temperature in the first heating–cooling process, and the elastomer exhibits an almost complete reversible deformation in the second heating–cooling process. By a comparison of the results of sample observation with those of X-ray analysis, we recognise that the strain λ was linearly coupled with the orientational order parameter S. In addition, the results of the X-ray analysis imply that a cybotactic nematic state, in which smectic clusters lie scattered in a nematic-like matrix, emerges after exposure to the isotropic phase. |
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| Keywords: | cybotactic nematics elastomers liquid-crystalline elastomers liquid-crystalline polymers polymer networks shape memory smectic clusters smectic liquid crystals |
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