Metastable wetting

Joel de Coninck (1) , Francois Dunlop (2) , Thierry Huillet (2)

1 LPSI - Laboratoire de Physique des Surfaces et des Interfaces
2 LPTM - UMR 8089 - Laboratoire de Physique Théorique et Modélisation

Consider a droplet of liquid on top of a grooved substrate. The wetting or not of a groove implies the crossing of a potential barrier as the interface has to distort, to hit the bottom of the groove. We start with computing the free energies of the dry and wet states in the context of a simple thermodynamical model before switching to a random microscopic version pertaining to the Solid-on-Solid (SOS) model. For some range in parameter space (Young angle, pressure difference, aspect ratio), the dry and wet states both share the same free energy, which means coexistence. We compute these coexistence lines together with the metastable regions. In the SOS case, we describe the dynamic transition between coexisting states in wetting. We show that the expected time to switch from one state to the other grows exponentially with the free energy barrier between the stable states and the saddle state, proportional to the groove's width. This random time appears to have an exponential-like distribution.

Mots clés: Wetting; metastable; Solid-on-Solid

Domaines: Mécanique statistique [cond-mat.stat-mech]

Joel de Coninck, Francois Dunlop, Thierry Huillet. Metastable wetting. Journal of Statistical Mechanics: Theory and Experiment, 2011, pp.P06013. ⟨10.1088/1742-5468/2011/06/P06013⟩. ⟨hal-00597462⟩