Phase Equilibria in Nematic Mixtures of Hard Uniaxial and Biaxial Particles

Abstract
Nematic and demixing behaviour of binary and ternary mixtures of rod- and platelike hard particles is studied using the off-lattice restricted-orientation model of rectangular parallelepipeds with the D_2h symmetry. It is shown that the region of a miscible nematic phase formed in rod/plate mixtures can be considerably broadened due to adding a cosolvent with particles of the appropriate shape and size. The results are compared with those of other molecular-statistical models. The phase equilibria of an experimental system are also reported which exhibits a behaviour close to the systems studied by model calculations.

Keywords: the Zwanzig model, rod-plate mixtures, demixing, biaxial nematic phase