Large-Scale Molecular Dynamics Study of Dewetting of Thin Liquid Films On Solid Substrates

The initial rupture of thin liquid films on a solid substrate has been extensively investigated in experiment and continuum theory regarding the interplay between two spontaneous mechanisms, i.e. spinodal instability and nucleation, at the early stage of dewetting. Molecular simulation becomes a powerful means for investigating the dewetting dynamics and structural changes at such a short time scale while ruling out heterogeneous nucleation, which would be almost inevitable in experiment. The enormous challenges, however, stem from the system size that should be sufficiently large to accommodate the tempo-spatial growth of unstable undulate modes in the film. Using LAMMPS GPU, a massively parallel Molecular Dynamics software package with graphics processing units acceleration, on Titan, we are now able to study metallic thin films at close-to-experiment length scales (i.e. hundreds of nanometers and micrometers), consisting of up to tens of millions of atoms. We found distinctive signatures of spinodal instability and thermal nucleation in these systems in remarkable agreement with previous experiments and theoretical predictions. Importantly, our results reveal insights into the early stage of dewetting at the atomistic level, which are inaccessible with continuum models and experiment.