Simulation study of discotic molecules in the vicinity of the isotropic–liquid crystal transition

Abstract

The equilibrium and microscopic properties of systems of discotic molecules have been investigated with Monte Carlo (MC) simulations. The study focuses on the behaviour of the fluid in the isotropic phase in the vicinity of the first liquid crystal transition, which involves either a nematic or a columnar phase. The molecules are modelled by rigid oblate spherocylinders with various types of interaction potentials. Molecular thickness/diameter ratios within L/D = 0.1–0.5 are considered. The MC equations of state are compared with theoretical predictions for hard convex bodies, based on molecular shape and virial expansions. A good agreement is found for the hard spherocylinder system, although discrepancies arise for L/D < 0.4 at sufficiently large packing fraction. Particular efforts are also devoted to characterising the formation of domains of stacked molecules in the isotropic phase for the different repulsive and attractive interaction models.