Phenomenological description of the crystal-liquid crystal phase diagram

Abstract

A new Landau-type phenomenological free energy function to describe the phase diagram of uniaxial anisotropic materials is proposed. The resulting phase diagram includes crystalline, smectic A, nematic and isotropic states, as well as a theoretically possible plastic solid state. Depending on the parameters of the free energy, smectic A phase may or may not be present for a given material. The obtained topologies of the temperature-pressure phase diagram qualitatively agree with results from computer simulations of model liquid crystalline materials.