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 Δμ from the bulk liquid-vapor coexistence. The strong influence of geometrical effects is manifested by a Δμ dependence of liquid adsorption Γ in the nanocavities that is stronger than the van der Waals behavior Γ∼Δμ-1/3 for flat surfaces. The observed Δμ 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. © 2005 The American Physical Society.