Bulk fluid phase behaviour of colloidal platelet-sphere and platelet-polymer mixtures

Abstract

Using a geometry-based fundamental measure density functional theory, we calculate bulk fluid phase diagrams of colloidal mixtures of vanishingly thin hard circular platelets and hard spheres. We find isotropic-nematic phase separation with strong broadening of the biphasic region upon increasing the pressure. In mixtures with large size ratio of platelet and sphere diameter, there is also demixing between two nematic phases with differing platelet concentrations. We formulate a fundamental-measure density functional for mixtures of colloidal platelets and freely overlapping spheres, which represent ideal polymers, and use it to obtain phase diagrams. We find that for low platelet-polymer size ratio in addition to isotropic-nematic and nematic-nematic phase coexistence, platelet-polymer mixtures also display isotropic-isotropic demixing. In contrast, we do not find isotropic-isotropic demixing in hard core platelet-sphere mixtures for the size ratios considered.

Accepted in Phil Trans A

References in corpus (8)

• Phase behavior of hard spheres confined between parallel hard plates: Manipulation of colloidal crystal structures by confinement
• The fluid-fluid interface in a model colloid-polymer mixture: Application of grand canonical Monte Carlo to asymmetric binary mixtures
• Depletion potentials in highly size-asymmetric binary hard-sphere mixtures: Comparison of accurate simulation results with theory
• Structure and thermodynamics of platelet dispersions
• Floating nematic phase in colloidal platelet-sphere mixtures
• Liquid crystalline phases and demixing in binary mixtures of shape-anisometric colloids
• Deriving the Rosenfeld Functional from the Virial Expansion
• Beyond the Rosenfeld Functional: Loop Contributions in Fundamental Measure Theory

Cited by in corpus (5)

• Hard-body models of bulk liquid crystals
• Tracking three-phase coexistences in binary mixtures of hard plates and spheres
• Depletion-driven four-phase coexistences in discotic systems
• Sedimentation of colloidal plate-sphere mixtures and inference of particle characteristics from stacking sequences
• Orientational ordering and layering of hard plates in narrow slit-like pores