The Influence of a Metastable Solid Phase on Eutectic Formation of a Binary Nematic Liquid Crystal

The existence of a metastable solid phase of p-azoxyanisole (PAA) influences the phase diagram of binary mixtures of PAA and p-azoxyphenetole (PAP). In addition to a stable binary system having a eutectic transformation to a nematic phase at 97°C for a PAA mole-fraction (XPAA) of 0.59, a metastable binary (eutectic point at 86°C for XPAA = 0.69) is also observed. The Schröder-van Laar equations describe the phase diagrams of both systems well using reasonable values of the solid-nematic transition energies for the pure components.