Decay of metastable states in wetting and dewetting transitions

Abstract

In a first-order wetting transition metastable surface states can be produced by overheating a nonwet wall or by undercooling a wetting layer covering the wall. These metastable states decay via the formation and subsequent growth of supercritical nuclei. The size and excess free energy of the critical nuclei diverge when some internal point on the line of phase transitions between wet and nonwet states is approached. For the case of overheating the critical nuclei are droplets on the wall, whereas for undercooling they are dents in the wetting layer. The critical droplets show a very different behaviour in the partial-wetting, complete-wetting and prewetting regimes. It is shown that the critical dents also differ significantly from each other in three regimes of the phase diagram which we denote by the partial-dewetting, dewetting and pre-dewetting regimes.