UC Berkeley

A computational multiscale Finite Element Method on dynamic wetting and droplet spreading on various substrates at micron scale is proposed. The model is formulated in the framework of large deformation continuum mechanics, and two different implementations are proposed to maintain the strain dependence of the surface stress.

We set forth a multiscale soft contact model and its Finite Element Method formulation for dynamic wetting, which includes an atomistic-based Coarse Grained Contact Model between the liquid and solid without using Molecular Dynamics, and the surface tension model along the contact interface allows droplet spreading due to the surface energy difference.

By employing the proposed method, we have successfully simulated droplet spreading, and our results compare well with the theoretical, experimental and Molecular Dynamics results. The results of the numerical simulation show that the proposed method is an efficient and viable computational tool for simulation of dynamic wetting, and it successfully removes the singularity problems that plague in most of macroscale hydrodynamics analysis of dynamic wetting and droplet spreading in the past.