Domains and walls in thermotropic liquid crystalline polymers an optical microscopy study

Abstract

Samples prepared from two thermotropic random copolyesters have been examined in an optical microscope, using extinction contrast between crossed polars, dichroic contrast in plane-polarized light and Zernicke phase contrast. Detailed interpretation of the microstructure leads to the identification of two boundary geometries, analogous to inversion walls of the first and second kinds. The observations confirm previous TEM studies. In addition they indicate that the optical properties of at least one of the polymers are biaxial, with the implication of long-range rotational correlations of the molecules about their chain axes.