Simulated growth of wetting films with a conserved order parameter.

Abstract

We have simulated the growth of saturated and unsaturated wetting films in two and three dimensions using an Ising lattice-gas model with nearest-neighbor interactions and a variety of long- and short-ranged adsorbate-substrate potentials. The Monte Carlo simulations provide a locally conserved order parameter (Kawasaki nearest-neighbor spin-exchange dynamics). Starting from a supersaturated bulk configuration, we find that the films grow as ${t}^{1/3}$ as predicted by Lifshitz and Slyozov. For an unsaturated bulk starting configuration, the film thickness appears to grow at intermediate times as ${t}^{\ensuremath{\theta}}$, where \ensuremath{\theta} is a small exponent which is determined by the substrate potential in the mean-field regime and which is universally (1/8 in the fluctuation regime; at long times, the thickness approaches the equilibrium thickness as ${t}^{\mathrm{\ensuremath{-}}1/2}$. These results are consistent with theoretical predictions made by Lipowsky and Huse.