CRITICAL NUCLEI FOR WETTING AND DEWETTING

In a first-order wetting transition it is possible to overheat a microscopic layer from below to above the wetting temperature T(w), and to undercool a macroscopic layer from above to below T(w). in both cases the transition to stable equilibrium occurs by formation and growth of supercritical nuclei. The critical nuclei for overheating are droplets on the wall of the system and for undercooling they are dents in the macroscopic layer. A recent calculation of the critical droplet in a special dimension d0 is now supplemented by the calculation of the critical dent for dewetting. Although the analytic expressions for the profiles are closely related, the nuclei above T(w) are finite whereas they are infinitely large below T(w). The latter is to be expected since the system is infinitesimally close to coexistence of wet and non-wet states at all temperatures T< T(w).