Thermodynamics of nematic liquid crystalline mixtures of similar molecules

Abstract

Mixtures ofthe first six members ofhomologous series 4,4'-di-n-alcoxyazoxybenzenes were investigated by DSC and HSM (heat stage microscopy) methods. A solid crystal (SC) form of the third member (C3) of the series is found which is virtual for the pure substance and is real for mixtures with the homologous. It is shown that a type of admixture C changes relative stability of SC forms K, K1, I2 of the pure C3. A eutectic manifestation of mixture (K1+K2) is found. Four SC forms of C3 have an equal enthalpy of transitions to a melt. Melting in the mesophase is accompanied by transformations of crystal structures.