Capillary nematization of hard colloidal platelets confined between two parallel hard walls

Abstract

We use density functional theory to study the capillary phase behaviour of a discotic system of colloidal platelets that are confined in a planar slit pore. The model plates have circular shape, continuous orientations and vanishing thickness; they interact via hard-core repulsion with each other and with the walls which induces homeotropic wall anchoring of the nematic director. We find that the isotropic–nematic capillary binodal is shifted to lower values of the chemical potential as compared to bulk isotropic–nematic coexistence. Capillary isotropic–nematic coexistence vanishes below a critical wall separation distance which is significantly larger than it is in a reference system of thin hard (Onsager) rods confined between two parallel hard walls that act on the particle centres.