A Van Der Waals Model for the Nematic Liquuid Crystal Mixtures

Abstract

Abstract Phase diagrams and excess molar volumes of binary nematogenic mixtures are investigated in the frame of a van der Waals - type theory for systems made up of hard rectangular parallelepipeds. It is shown that the excess volumes can be positive or negative or can change sign depending on temperature and composition. In agreement with experiment the model predicts a coexistence of two nematic phases for mixture of rod-like and plate-like molecules.