Abstract
When confined in a thin parallel cell, a liquid crystal solution of a polysaccharide schizophyllan formed a planar texture and showed very strong optical rotatory power. The wavelength dependence of the optical rotatory power was represented by a simple equation of the Drude type and differed from that of an isotropic solution which obeyed a Moffitt-Yang type equation. The data at longer wavelengths were consistent with the prediction by the de Vries theory of cholesterics, yielding a layer birefringence approximately proportional to the polymer concentration. The intrinsic birefringence of a schizophyllan triple helix was estimated to be about 0.02, which is much smaller than that of xanthan and the birefringence of crystalline cellulose. The difference in birefringence was ascribed to the difference in chain conformation among these glucans. An abrupt change in ORD behavior occurred when an isotropic solution was cooled down to a temperature close to the isotropic-biphasic boundary temperature, indicating the occurrence of a pretransition from isotropic to cholesteric phases.
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Van, K., Asakawa, T. & Teramoto, A. Optical Rotatory Dispersion of Liquid Crystal Solutions of a Triple-Helical Polysaccharide Schizophyllan. Polym J 16, 61–69 (1984). https://doi.org/10.1295/polymj.16.61
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DOI: https://doi.org/10.1295/polymj.16.61