Figure 2.

Spatial dependence of the density and relaxation of films. (a) Representative monomer density profile of ρ(z) for a supported film on an attractive surface for a range of T for film thickness h_g = 15.03, corresponding to about 30 nm in physical polymer units. It is apparent from ρ(z, T) that the thickness of the film decreases on cooling. The inset shows the density profile of monomers for various thicknesses scaled by the bulk value. We see that the peaks are independent of film thickness and that there is a bulk-like region far from the interfaces. (b) Relaxation time τ_s as function of distance z from the wall for various T for h_g = 15.03. τ_s(z) is altered from the bulk, even near the center of the film where the density is the same as the bulk. The deviation of τ_s from the bulk becomes more significant at low temperature.