Adsorption properties of a colloid-polymer mixture confined in a slit pore.

The soft fundamental-measure theory, which was based on the additive colloid-polymer mixture [M. Schmidt, Phys. Rev. E 62, 3799 (2000)] has been employed to investigate the adsorption of a colloid-polymer mixture within a hard slit pore. The calculated results show that the adsorption for the confined colloid-polymer mixture is very different from those of the colloid-colloid and polymer-polymer mixtures. The equilibrium particle density distribution strongly depends on the softness of a star polymer. The local relative concentration oscillates with a spatial period close to the diameter of a large particle in the same way as the equilibrium particle density distribution. The size selectivity in adsorption depends both on the softness of a star polymer and on the particle size ratio in a binary mixture. In particular, the strong adsorption occurs at the ultra-soft polymer and high bulk packing fraction.