Regimes of Wetting Transitions on Superhydrophobic Textures Conditioned by Energy of Receding Contact Lines

TL;DR

This paper investigates evaporation-induced wetting transitions on superhydrophobic stripes, revealing how the elastic energy of the contact line influences whether a sudden impalement or slow impregnation occurs.

Contribution

It introduces a new understanding of how the elastic energy of the receding contact line determines different wetting transition regimes on textured surfaces.

Findings

Receding contact angle varies with stripe density.

Sudden impalement occurs at angles above 90° in dilute stripes.

Slow impregnation initiates at 90° in dense stripes.

Abstract

We discuss an evaporation-induced wetting transition on superhydrophobic stripes, and show that depending on the elastic energy of the deformed contact line, which determines the value of an instantaneous effective contact angle, two different scenarios occur. For relatively dilute stripes the receding angle is above 90$^\circ$, and the sudden impalement transition happens due to an increase of a curvature of an evaporating drop. For dense stripes the slow impregnation transition commences when the effective angle reaches 90$^\circ$ and represents the impregnation of the grooves from the triple contact line towards the drop center.