Liquid bridge splitting enhances normal capillary adhesion and resistance to shear on rough surfaces

TL;DR

This paper investigates how splitting a liquid bridge into multiple smaller bridges can enhance capillary adhesion and shear resistance on rough surfaces, especially when the total liquid volume is fixed.

Contribution

It demonstrates that bridge splitting significantly increases capillary adhesion and shear resistance on rough surfaces, extending previous findings to more realistic rough surface conditions.

Findings

Bridge splitting enhances adhesion force on rough surfaces.

Shear resistance scales linearly with translation velocity due to bridge splitting.

Significant adhesion increase occurs when one surface is rough.

Abstract

The effect of 'bridge splitting' is considered in the case of capillary adhesion: for a fixed total volume of liquid, does having more capillary bridges increase the total adhesion force? Previous studies have shown that the capillary-induced adhesion force between two planar surfaces is only substantially enhanced by bridge splitting in specific circumstances. Here this previous result is reconsidered, and it is shown that bridge splitting may significantly increase the adhesion forces when one of the surfaces is rough. The resistance to shear is also examined, and it is shown that bridge splitting on a rough surface can lead to a steady capillary-induced shear force that scales linearly with translation velocity, even in the absence of contact-line pinning.