title: Growth dynamics of water drops on a square-pattern rough hydrophobic surface.
abstract: Condensation on rough or superhydrophobic substrates can induce wetting behavior that is quite different from that of deposited or impinging drops. We investigate the growth dynamics of water drops in a well-controlled condensation chamber on a model rough hydrophobic surface made of square pillars. After having followed growth laws similar to those observed on flat surfaces, a transition to an air-pocket-like state occurred because of the bridging of the drops between the pillars. Another transition to the more stable Wenzel state is later ensured by a noticeable pillar self-drying process. Condensation ends up in a few large drops in a mixed Wenzel penetration regime. The drops are fed by neighboring channels and the adjacent pillars stay almost dry, a remarkable and seemingly general property of rough hydrophobic substrates.
authors.affiliation: Equipe du Supercritique pour l'Environnement, les Matériaux et l'Espace, Laboratoire de Physique et Mécanique des Milieux Hétérogènes, Ecole Supérieure de Physique et Chimie Industrielle et Universités Paris 6 et Paris 7, Paris Cedex 05, France.
authors.forename: R D
authors.initials: RD
authors.lastname: Narhe
authors.forename: D A
authors.initials: DA
authors.lastname: Beysens
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D008962:Models, Theoretical; D014867:Water
chemical_list: D014867:Water