Surface segregation in the minority component of the binary polymer mixture

According to a common viewpoint the surface of the binary polymer mixture A/B could be enriched only in one component, say A, regardless of the value of its bulk volume fraction φ bulk . From recent theoretical analyses and Monte Carlo simulations one can expect however that some mixtures can exhibit surface segregation in the minority blend component, i.e. enrichment in the component A for φ bulk φ bulk >50%. Using composition-depth profiling techniques, we have observed both types of the segregation with only one- or both-blend component(s) preferred at the surface. These results were obtained for model mixtures composed of partly deuterated (dx) and protonated (hx) random olefinic copolymers of the structure –[C 4 H 8 ] 1- x [C 2 H 3 (C 2 H 5 )] x –. A simple mean-field model is presented to explain both situations.