Lattice Model Studies of Nematic Liquid Crystalline Mixtures: Effects of Molecular Flexibility

Abstract

A simple cubic lattice model by DiMarzio is applied to the study of the nematic-isotropic phase transitions in liquid crystalline mixtures. The order parameters of rigid cores and of completely flexible tails of molecules, transition entropies, and density changes at the transitions are numerically calculated in some binary systems. In addition, the phase diagrams of them are evaluated. The present results show that in most cases the nematic-isotropic transition temperatures in the binary mixture of nematogens are lower than the linearly interpolated values. However, for the mixture of components with the same ratio of the flexible chain length to rigid core, such lowering of nematic-isotropic transition temperatures does not be found.