DYNAMICS OF FLUID SPREADING - A SOLID-ON-SOLID MONTE-CARLO STUDY

We study the spreading of both a fluid wedge and a droplet in two dimensions by means of Monte Carlo simulations of a solid-on-solid model. For the case of the fluid wedge, our results confirm those of Abraham, Heinio, and Kaski [J. Phys. A 24, L309 (1991)] who have done analogous simulations. For the case of the droplet, both wetting and partial-wetting behaviors are observed, depending on the relative strength of the fluid's interparticle interactions and the particle-substrate interaction. For the wetting case, a single-layer precursor film is found to spread at the expense of the remainder of the droplet. In the partial-wetting case, and starting from an initial droplet configuration which is narrower than the equilibrium configuration, the droplet width is found to increase with time until the equilibrium configuration is attained. The time dependence of the width demonstrates apparently universal behavior, independent of the relative strength of the interparticle interactions and the particle-substrate interaction. Our results are compared with earlier theoretical work and numerical simulations, and connections established with experimental measurements.