The fluid-fluid interface of a model colloid-polymer mixture

A simple density functional approach is used to calculate the surface tension and density profiles of the interface between demixed fluid phases for a model colloid-polymer mixture. Using an effective one-component Hamiltonian for the colloids, obtained by integrating out the degrees of freedom of the polymer, we find that, when correctly scaled, the surface tension takes values which are close to those of a simple liquid. Our results for the surface tension and density profiles are in reasonable agreement with those of recent experiments