A Thermal Transition in a Cholesteric Liquid Crystal of Aqueous Schizophyllan

Abstract

Optical rotation and laser diffraction measurements were made on cholesteric solutions of a triple helical polysaccharaide schizophyllan. It was found that optical rotation Θ and cholesteric pitch P changed abruptly at about 7°C when the temperature was changed. These abrupt changes in Θ and P were accompanied by a small but distinct endothermic peak on a DSC thermogram. It was concluded that the cholesteric phase of aqueous schizophyllan underwent a thermal structure transition just above its freezing point, which probably proceeded in two stages: a change in solvation of schizophyllan triple helices followed by re-orientation of the solvated helices.