Dewetting of thin polymer film on rough substrate: I. Theory

Abstract

The dewetting process of spinodally unstable thin film on rough substrates is considered. The theoretical consideration is based on the force model of substrate–film interactions. The competition between spinodal dewetting and dewetting due to substrate roughness is analysed and an analytical solution for the structure of the dewetted film has been discovered. We found conditions where the lateral periodicity of a substrate surface profile is smaller than the critical spinodal wavelength of a film and the roughness of the surface is large enough to initiate dewetting due to substrate roughness; then the dewetted film patterns repeat the substrate structure corresponding to lateral periodicity of a substrate surface profile. In other cases, the film spinodally dewets with a lateral scale close to the dominant spinodal wavelength.