Stick-Slip Sliding of Water Drops on Chemically Heterogeneous Surfaces

TL;DR

This study investigates the stick-slip motion of water drops on chemically patterned surfaces, revealing that the heterogeneous pattern significantly reduces sliding speed due to interface deformations, supported by experiments and simulations.

Contribution

It provides a detailed analysis of how chemical heterogeneity influences drop dynamics, combining experimental and numerical approaches to uncover underlying mechanisms.

Findings

Drop speed is an order of magnitude lower on patterned surfaces.

Stick-slip motion results from periodic interface deformations.

Numerical simulations confirm experimental observations.

Abstract

We present a comprehensive study of water drops sliding down chemically heterogeneous surfaces formed by a periodic pattern of alternating hydrophobic and hydrophilic stripes. Drops are found to undergo a stick-slip motion whose average speed is an order of magnitude smaller than that measured on a homogeneous surface having the same static contact angle. This motion is the result of the periodic deformations of the drop interface when crossing the stripes. Numerical simulations confirm this view and are used to elucidate the principles underlying the experimental observations.