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Thermalexpansion of liquid crystalline amphiphilic di-block copolymer observed bysimultaneous DSC-XRD
Authors:R. Watanabe  T. Iyoda  T. Yamada  H. Yoshida
Affiliation:(1) Chemical Resources Laboratory, Tokyo Institute of Technology, Kanagawa Japan, 226-8503, 4259 Nagatsuta-cho, Midori-ku, Yokohama;(2) Graduate School of Engineering, Tokyo Metropolitan University, Tokyo Japan, 192-0397, 1-1 Minamiosawa, Hachioji;(3) Faculty of Urban Environment Science, Tokyo Metropolitan University, Tokyo Japan, 192-0397, 1-1 Minamiosawa, Hachioji;(4) JST-CREST, Saitama Japan, 332-0012, 4-1-8 Honmachi, Kawaguchi
Abstract:Phase transition process of PEOm-b-PMA(Az)n was investigated by the simultaneous DSC-XRD measurement using the synchrotron radiation facility. Four endothermic DSC peaks were observed during heating process. These DSC peaks were assigned to the melting of PEO, the transition from SmX, which is a mixture of super-cooled SmC and crystal, to SmC, from SmC to SmA, and from SmA to isotropic liquid state as determined by XRD profiles. In SmC phase, the liner expansion coefficient calculated from the spacing variation of the smectic layer distance was larger than that of the other phases. This result reflected the fact azobenzene moieties in the long-side chains of PMA(Az)n forming the smectic layers and then they were tilted and stood up during the heating process.
Keywords:amphiphilic di-block copolymer  azobenzene  DSC-XRD  liquid crystalline polymer  smectic phase  thermal expansion
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