A multiscale model to describe the wetting of solid surfaces

Interface properties between liquids and solids determine the adhesion, friction, and wettability response of surfaces in various applications of engineering interest. However, the multiscale nature of these phenomena limits bottom-up prediction of the resulting surface properties.

In this work, we use computational experiments to characterize solid surfaces and reproduce the dynamics of a droplet on a surface. First, we adopt molecular dynamics simulations to compute the work of adhesion (Wad), solid-liquid interface tension (γsl), and slip length using the free energy perturbation (FEP) approach and the Green-Kubo relation, respectively. The obtained results are validated against experiments and then used as boundary conditions for a continuous model based on the phase field method in terms of the wetted wall and friction coefficient in the Navier slip. We explore the impact and spread of the droplet on the surface and compare the results with experiments.

This numerical approach allows us to understand and decouple the different mechanisms governing the wetting properties of solid surfaces. The goal is to propose a multiscale framework for the computational characterization of surfaces, which is necessary for the optimal design of materials with tailored surface properties.