Dewetting of a Polymer Melt on a Chemically Identical Brush

The use of an end-grafted polymer or oligomer layer has been a popular means of engineering surfaces with designable wetting properties. We investigated the factors governing the equilibrium states of the autophobic polystyrene/polystyrene brush/SiO$_{2}$/Si model system, namely the ratio of the molecular weight of the homopolymer to that of the brush, $r$, and the grafting density of the brush, $\sigma $. We found that the wettability of the polymer melt film on the brush -- as measured by the residual thickness, $d$, of the final dewetted film -- decreased monotonically with increasing $r$ or $\sigma $. The experimentally determined form of the $d(r$,$\sigma )$ curves and the polymer-brush interfacial tensions can be described reasonably well by the self-consistent field theory.