High pressure studies on polymorphic liquid crystals

Abstract

The effect of pressure on phase transitions has been studied for four compounds, viz., di-ethyl-p-azoxybenzoate, 4-nitrophenyl-4'-octyloxybenzoate, 4-n-pentyloxyphenyl-4'-n-decyloxybenzoate and 4-n-heptyloxyphenyl-4'-n-decyloxybenzoate, which exhibit different types of mesophases at atmospheric pressure. The experimental phase diagrams are presented and the dT/dP values of the various transitions as well as the volume change at these transitions are evaluated.