Properties of a liquid crystalline polyester with a mesogen containing the bicyclooctylene ring

Abstract

A liquid crystalline polyester with a decamethyene flexible spacer and a mesogenic unit containing a central 1,4-bicyclo(2,2,2)octylene ring was prepared for comparison with the equivalent polymer containing a central p-phenylene ring in the mesogen. Both polymers formed a nematic phase on melting, and as expected, the former had a much lower isotropization temperature than the latter. The polymer containing the bicyclooctylene ring, however, showed a batonnet texture, indicative of a smectic phase, at a temperature above that of the nematic state, especially on cooling from the isotropic melt.