Lateral Drop Rebound on Hydrophobic and Chemically Heterogeneous Surface

TL;DR

This study uses the lattice Boltzmann method to analyze how drops rebound on hydrophobic and chemically heterogeneous surfaces, revealing how surface properties influence rebound direction and height.

Contribution

It demonstrates the impact of surface heterogeneity and hydrophobicity on drop rebound behavior, providing insights into controlling drop dynamics on complex surfaces.

Findings

Drop rebound height increases with surface hydrophobicity on homogeneous surfaces.

Drops rebound laterally towards less hydrophobic areas on heterogeneous surfaces.

Unbalanced Young's force causes asymmetrical rebound on chemically heterogeneous surfaces.

Abstract

A drop rebounding from a hydrophobic and chemically heterogeneous surface is investigated using the multiphase lattice Boltzmann method. The behaviors of drop rebounding are dependent on the degrees of the hydrophobicity and heterogeneity of the surface. When the surface is homogeneous, the drop rebounds vertically and the height is getting higher and higher with increases of the surface hydrophobicity. When the surface consists of two different hydrophobic surfaces, the drop rebounds laterally towards the low hydrophobic side. The asymmetrical rebounding is because the unbalanced Young's force exerted on the contact line by the high hydrophobic side is greater than that by the low hydrophobic surface. A set of contours of momentum distribution illustrate the dynamic process of drop spreading, shrinking and rebounding. This work promotes the understanding of the rebound mechanism of a drop impacting the surface and also provides a guiding strategy for precisely controlling the lateral behavior of rebounding drops by hydrophobic degrees and heterogeneous surfaces.