Orientational wetting and capillary nematization of hard-rod fluids

We investigate the phase behavior of colloidal hard-rod fluids near a single wall and confined in a slit pore. Zwanzig's hard-rod model is analyzed by minimization of a free energy functional, and a system of freely rotating spherocylinders is studied by Monte Carlo simulations. Both theory and simulation show i) a wall-induced surface transition from uniaxial to biaxial symmetry, ii) complete orientational wetting of the wall-isotropic fluid interface by a nematic film, and iii) capillary nematization, with a capillary critical point, induced by confinement in the slit pore