Global phase diagram for anisotropic binary fluid mixtures: reverse type IV behaviour

Abstract

Calculations of the critical properties of anisotropic binary mixtures are reported using the hard convex body-van der Waals equation of state in conjunction with conformal solution theory and the one-fluid model. The calculations are used to determine the global phase diagram for anisotropic binary mixtures of molecules of identical size. In the absence of other influences, mixtures with a moderate degree of anisotropy between the component molecules are only observed to exhibit type I, II or III behaviour. For highly anisotropic mixtures, a new type of behaviour is observed which we describe as ‘reverse type IV’.