Interfacial phenomena in thin polymer films: Phase coexistence and segregation

Interfaces formed or exposed by polymer mixtures are often employed in mode rn technological applications. This is especially true for thin polymer fil ms used nowadays in photoresist lithography, electrooptical devices or nano meter-scale surface patterning. Apart from these technology-oriented aspect s the interfacial phenomena in thin polymer films pose a fundamental scient ific challenge to physics of polymers and thermodynamics of condensed matte r. This work reviews experimental results on the equilibrium properties of interfaces created by polymer mixtures confined in thin films. It confronts experimental data with theoretical expectations based mainly on mean field models. Most of the data have been obtained by high resolution profiling t echniques emerged in the last decade. These techniques allow us to trace co ncentration vs depth profiles across a thin him with a depth resolution bet ter than the characteristic size of a polymer coil. The interfacial phenome na of phase coexistence and segregation are described as observed in thin p olymer films. This work also considers related issues in the focus of curre nt research such as wetting phenomena, finite size effects expected in very thin films, surface (and bulk) properties of mixtures with stiffness dispa rity and conformational properties of end-segregated macromolecules forming polymer brushes.