Wetting transition in a binary polymer blend

Abstract
We have used composition depth profiling,based on nuclear-reaction analysis and secondary ion mass spectroscopy,to study segregation at the free surface of a partly miscible binary mixture consisting of random olefinic copolymers. The equilibrium surface excess data,analysed within a mean-field Cahn approach,point to a wetting transition. The surface phase diagram obtained was confirmed by the observed dynamics of the segregation from a coexistence composition: the monotonic and halted growth of the surface layer was observed at temperatures above and below the predicted wetting point,respectively.