Disc-like mesogens

Abstract

The paper deals with a study of the thermotropic mesophases observed in systems of disc-like molecules, viz., pure benzene-hexa-n-alkanoates and their mixtures with benzene. The mesophases exhibit optical textures that are typical of a lamellar type of liquid crystal. The X-ray data for the pure compounds are consistent with a structure in which there is lamellar order with hexagonal symmetry in two dimensions and liquid-like disorder in the third. Preliminary NMR results are described, which again indicate that the degree of molecular order in the mesophase is intermediate between those in the solid and isotropic phases. Pressure-temperature phase diagrams are presented for two of the homologues, the hexanoate and octanoate compounds.