Phase Diagrams of Binary Liquid Crystal Mixtures

Abstract

A series of four binary mixtures of smectic liquid crystalline compounds was prepared and their thermodynamic properties measured by differential thermal calorimetry. Calculations using ideal solution theory were carried out and were compared to the experimental phase diagrams. Plots of ideal ΔH and ΔS values for the mixtures were also prepared and were compared to experiment. It is concluded that large deviations from ideality are caused by a great variety of very subtle electronic and geometric forces present in the mixtures, and that no one of the explanations put forward to date is of itself adequate to describe the observed deviations from ideality.