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Title: Volume phase transitions of cholesteric liquid crystalline gels

Abstract

We present a mean field theory to describe anisotropic deformations of a cholesteric elastomer without solvent molecules and a cholesteric liquid crystalline gel immersed in isotropic solvents at a thermal equilibrium state. Based on the neoclassical rubber theory of nematic elastomers, we derive an elastic energy and a twist distortion energy, which are important to determine the shape of a cholesteric elastomer (or gel). We demonstrate that when the elastic energy dominates in the free energy, the cholesteric elastomer causes a spontaneous compression in the pitch axis and elongates along the director on the plane perpendicular to the pitch axis. Our theory can qualitatively describe the experimental results of a cholesteric elastomer. We also predict the first-order volume phase transitions and anisotropic deformations of a gel at the cholesteric-isotropic phase transition temperature. Depending on a chirality of a gel, we find a prolate or oblate shape of cholesteric gels.

Authors:
 [1]
  1. Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka 820-8502 (Japan)
Publication Date:
OSTI Identifier:
22415754
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 142; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANISOTROPY; CHIRALITY; COMPRESSION; DEFORMATION; FREE ENERGY; GELS; MEAN-FIELD THEORY; MOLECULES; NEOCLASSICAL TRANSPORT THEORY; PHASE TRANSFORMATIONS; RUBBERS; SOLVENTS; THERMAL EQUILIBRIUM; TRANSITION TEMPERATURE

Citation Formats

Matsuyama, Akihiko, E-mail: matuyama@bio.kyutech.ac.jp. Volume phase transitions of cholesteric liquid crystalline gels. United States: N. p., 2015. Web. doi:10.1063/1.4919651.
Matsuyama, Akihiko, E-mail: matuyama@bio.kyutech.ac.jp. Volume phase transitions of cholesteric liquid crystalline gels. United States. doi:10.1063/1.4919651.
Matsuyama, Akihiko, E-mail: matuyama@bio.kyutech.ac.jp. Thu . "Volume phase transitions of cholesteric liquid crystalline gels". United States. doi:10.1063/1.4919651.
@article{osti_22415754,
title = {Volume phase transitions of cholesteric liquid crystalline gels},
author = {Matsuyama, Akihiko, E-mail: matuyama@bio.kyutech.ac.jp},
abstractNote = {We present a mean field theory to describe anisotropic deformations of a cholesteric elastomer without solvent molecules and a cholesteric liquid crystalline gel immersed in isotropic solvents at a thermal equilibrium state. Based on the neoclassical rubber theory of nematic elastomers, we derive an elastic energy and a twist distortion energy, which are important to determine the shape of a cholesteric elastomer (or gel). We demonstrate that when the elastic energy dominates in the free energy, the cholesteric elastomer causes a spontaneous compression in the pitch axis and elongates along the director on the plane perpendicular to the pitch axis. Our theory can qualitatively describe the experimental results of a cholesteric elastomer. We also predict the first-order volume phase transitions and anisotropic deformations of a gel at the cholesteric-isotropic phase transition temperature. Depending on a chirality of a gel, we find a prolate or oblate shape of cholesteric gels.},
doi = {10.1063/1.4919651},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 17,
volume = 142,
place = {United States},
year = {2015},
month = {5}
}