Imbibition of solids in nanopillar arrays

The imbibition of a solid island on a substrate with a square array of pillars is studied by means of kinetic Monte Carlo simulations. Imbibition is found to occur via an intermediate state where an island sits on the film. Two dynamical regimes are identified depending on the geometry of the substrate: a stochastic regime, where the dynamics are controlled by the nucleation-limited motion of the imbibition front across the array of pillars, and a deterministic regime limited by the diffusion of atoms on top of the imbibition film.