Synthesis and Liquid Crystallinity of Polymers Substituted with Aromatic Amide Mesogens

摘要

In a side chain liquid crystal polymer, if the mesogenic units are attached laterally to the main chain through no or only very short spacers, a "jacket" will be formed around the main chain by the mesogenic side groups. Studies (1) on such mesogen-jacketed liquid crystal polymers (MJLCPs) as poly-2,5-bis[(4 -methoxybenzoyl)oxy]styrene (PBMBS) and its homologues have shown that the polymers with such unique a molecular structure have significant chain rigidity compatible with that of main-chain type liquid crystalline aromatic polyesters. Evidence for the chain rigidity of PBMBS includes the large value of persistence length (12 nm), a high value (0.82) of the exponent parameter of the Mark-Houwink-Sakurada equation, the very high thermal stability of the nematic phase, and the formation of the banded textures of a nematic film.