Solution landscape of droplet on rough surfaces: wetting transition and directional transport

TL;DR

This paper develops a phase-field saddle dynamics method to map all stable and transitional states of droplets on rough surfaces, revealing mechanisms for wetting transitions and directional transport influenced by surface design.

Contribution

It introduces a novel computational approach to systematically explore the solution landscape of droplet wetting and transport on textured surfaces.

Findings

Mapped full range of Cassie-Baxter and Wenzel states

Identified wetting transition pathways

Demonstrated surface design influence on directional transport

Abstract

Droplets on rough surfaces can exhibit various stationary states that are crucial for designing hydrophobic materials and enabling directional liquid transport. Here we introduce a phase-field saddle dynamics method to construct the solution landscape of wetting transition and directional transport on pillared substrates. By applying this method, we reveal the full range of Cassie-Baxter and Wenzel states, along with the complete wetting transition paths. We further elucidate the mechanisms of directional droplet transport on both hydrophobic and hydrophilic surfaces, demonstrating how surface design can influence directional movement.