Liquids on topologically nanopatterned surfaces

We report here surface x-ray scattering studies of the adsorption of simple hydrocarbon liquid films on nanostructured surfaces-silicon patterned by an array of nanocavities. Two different regimes, filling and growing, are observed for the wetting film evolution as a function of the chemical potential offset Delta mu from the bulk liquid-vapor coexistence. The strong influence of geometrical effects is manifested by a Delta mu dependence of liquid adsorption Gamma in the nanocavities that is stronger than the van der Waals behavior Gamma similar to Delta mu(-1/3) for flat surfaces. The observed Delta mu dependence is, however, much weaker than predicted for the infinitely deep parabolic cavities, suggesting that the finite-size effects contribute significantly to the observed adsorption behavior.