Experimental Methods for Determining the Eutectic Composition of a Multi-Component Liquid Crystal Mixture

Abstract

Abstract Experimental techniques are described for determining the eutectic composition of multicomponent mixtures of nematic liquid crystals. These techniques were applied to the formulation of nematic esters, when the idealized eutectic composition calculated by the Schroeder-Van Laar relationship did not give a good melting point minimum for the mixture. One experimental procedure was based on the assumption that the composition of the initial nematic melt from a frozen, crystallized mixture is closer to a true eutectic than is the calculated value from which the frozen mixture was formulated. Another experimental procedure was based on the assumption that a new eutectic could be obtained by adding small amounts of a new component to an existing multicomponent eutectic mixture, using the a plot of the melting point versus the percentage of the new component added to determine a new eutectic mixture corresponding to a new melting point minimum. High performance liquid chromatography was used to estimate the purity of each component, and to analyze quantitatively the component composition of each melt. The calibration plots for each liquid crystal component, as well as the chromatographic analysis of the mixtures are shown.