Rehyphen;entrant isotropic phase of a polypeptide liquid crystal

摘要

Optical and Chyphen;13 NMR examinations of concentrated solutions of polyhyphen;ggr;hyphen;benzylhyphen;Lhyphen;glutamate (PBLG) in a mixed solvent system containing a denaturant acid, show that this polymer liquid crystal has both a low and high temperature isotropic phase. The latter is due to thermal disruption of longhyphen;range orientational order of the elongated macromolecules. The former rehyphen;entrant isotropic phase is a result of an intramolecular helix to random coil transition, which leads to a macromolecular conformation inconsistent with liquid crystallinity.