Effect of molecular structure on the phase behaviour of some liquid crystalline compounds and their mixtures IX. Multi-mixtures of a monotrope and enantiotropes

Abstract

Transition temperatures of the ternary and quaternary mixtures, prepared from the enantiotropic cyano and nitro derivatives of the two series, 4-hexadecyloxyphenyl 4-substituted benzoates (Ia,b) and 4-substituted phenyl-4'-hexadecyloxy benzoates (IIa,b) with the monotropic methoxy derivative (IIc), have been determined by DSC and identified with polarized light microscopy. The equation deduced to calculate the eutectic composition of a multicomponent system from values determined for their individual binary systems, was found to be fairly applicable to our non-ideal systems. Conversely, values of clearing temperatures (Tc), calculated from the polarizability anisotropy (ΔαX) of the individual CAr-X bonds, are often less than those measured, indicating complex formation between the methoxy and nitro derivatives.