Spontaneous Wenzel to Cassie dewetting transition on structured surfaces

Most superhydrophobic surfaces undergo a wetting transition from the Cassie to the Wenzel state, either spontaneously or under the action of external perturbations. The reverse dewetting transition is hampered by a large energy barrier and in order to achieve it, external fields are usually applied. Here we perform experiments, theoretical analysis, and lattice Boltzmann simulations of droplet condensation on a patterned superhydrophobic surface and demonstrate that the dewetting energy barrier can be reduced by manipulating the adhesion forces. Moreover, the kinetics of dewetting is a result of a subtle interplay of wetting and adhesion and in certain geometries, such as cone-shaped texture, the dewetting transition from Wenzel to Cassie state becomes spontaneous.