Year: 2025
Type: article
Abstract: The motion of contact line plays a crucial role in both natural phenomena and industrial processes. While it is well known that surface defects influence contact line dynamics, we demonstrate that their impact depends not only on geometry, size, and composition, but also on the history of fluid interaction with the surface. Using ultrafast, high‐resolution reflection microscopy, we visualized the dynamics of the three‐phase contact line as successive water droplets slid across a hydrophobic surface patterned with protrusions. We observed a growing attraction between the contact line and surface defects with increasing drop number. This effect arises from the spontaneous electrification that occurs during sliding: the droplets and the surface acquire opposite charges, generating electrostatic forces that significantly influence both advancing and receding contact lines. These forces contribute more than half of the total pinning force. Our findings reveal a previously overlooked factor in drop sliding and offer new insights into the dynamics of the contact line.
Source: Droplet
DOI: 10.1002/dro2.70039
Authors: Yaolei Xiang, Benedikt Straub, Diego Cortes, Hans‐Jürgen Butt, Kaloian Koynov
Institution: Max Planck Institute for Polymer Research
Language: English
Subfield: Surfaces, Coatings and Films
Field: Materials Science
Domain: Physical Sciences
Open Access status: diamond
Awards: G1985494508, G434337789, G4935919731
OpenAlex ID: W4417104863