Esters that Exhibit Smectic F to Isotropic Liquid Phase Transitions

Abstract

A number of esters of the type, 4-n-alkanoyloxy 4′-n-octyloxybiphenyl have been synthesized, and shown to exhibit direct isotropic liquid to hexatic smectic F phase transitions on cooling. The natural texture of the smectic F phase characterized by this transition separates from the isotropic liquid in the form of spherulites which have a hexagonal cross of optical discontinuity centered in them. Previously synthesized materials in which the direction of the ester function is reversed exhibit orthogonal hexatic B rather than tilted hexatic phases. This behavior can be linked directly to the extent of the polarization of the delocalized π electrons in the central aromatic core.