Tunable attractive interaction and the phase diagram of a system of Gay-Berne ellipsoids: A density functional approach

Density functional theory has been used to investigate the effect of the variation of attractive interaction on phase diagram of a system of axially symmetric liquid crystalline molecules interacting via Gay-Berne intermolecular potential. The pair correlation functions of the isotropic fluid, used as structural input in the density functional theory have been calculated by using Percus-Yevick integral equation theory. Considering the isotropic, nematic and smectic A phases as the candidate structures, we observe that the transition parameters and the topology of the phase diagram changes significantly with the variation in the strength of attractive interaction between the molecules. The dominance of the attractive interaction over repulsive one, is found to cause an enhanced tendency of the system to freeze into smectic A phase. Both isotropic-nematic and nematic-smectic A transition densities and pressure are found to decrease as we increase the strength of the attraction among the particles. The pair correlation functions and phase transition parameters are compared with the available computer simulation results of the similar model potential and are found to be in good qualitative agreement. (C) 2016 Elsevier B.V. All rights reserved.