  We investigate the phase behavior of athermal polymer/nanoparticle blends
near a hard substrate. We apply the density functional theory of Tripathi and
Chapman to these blends. We find a first order phase transition where the
nanoparticles expel the polymer from the surface to form a monolayer. The
transition density depends on the polymer length and the system bulk density.
The effect is due to the packing entropy of the species and configurational
entropy of the polymer. The simplicity of the system allows us to understand
the so-called ``entropic-push'' observed in experiments.

Soft Condensed Matter