Wetting properties of structured interfaces composed of surface-attached spherical nanoparticles

The influence of the external pressure and surface energy on the wetting transition at nanotextured interfaces is studied using molecular dynamics and continuum simulations. The surface roughness of the composite interface is introduced via an array of spherical nanoparticles with controlled wettability. We find that in the absence of an external pressure, the liquid interface is flat and its location relative to the solid substrate is determined by the particle size and the local contact angle. With increasing pressure on the liquid film, the interface becomes more curved and the three-phase contact line is displaced along the spherical surface but remains stable due to re-entrant geometry. It is demonstrated that the results of molecular dynamics simulations for the critical pressure of the Cassie-Baxter wetting state agree well with the estimate of the critical pressure obtained by numerical minimization of the interfacial energy.