Adsorption and Wetting of Component Surfaces

The wetting properties of component surfaces are important in many technical applications. They depend on the wetting liquid and the morphology of the component surface, including the adsorption layer, which is always present on technical surfaces. Both wetting and adsorption are governed by the same molecular interactions, and it is highly interesting to study the influence of these interactions on macroscopic wetting and adsorption behavior. This was done here in a scale-bridging approach by coupling molecular dynamics simulations with phase field simulations in a consistent way by a molecular-based equation of state. Systematic studies of wetting and adsorption in dispersive model systems were carried out, which, however, exhibit basically all phenomena observed in real systems. These simulation studies were complemented by experiments, in which contact angle measurements were combined with X-ray photoelectron spectroscopy (XPS) surface analytics. The results demonstrate that the wetting of technical surfaces is dominated by the adsorption layer. The substrate’s role is only indirect: It influences the morphology of the surface layer.