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

Matthew Butler, Dominic Vella

Research output: Contribution to journalArticlepeer-review

Abstract

Hypothesis: ‘Bridge splitting’ is considered in the case of capillary adhesion: a fixed total volume of liquid is split into multiple capillary bridges. Previous studies have shown that bridge splitting only enhances the capillary-induced adhesion force between two planar surfaces in specific circumstances. We hypothesise that bridge splitting significantly enhances the total adhesion force between rough surfaces, since mobile wetting bridges can naturally migrate to narrower gaps. This migration of capillary bridges should also provide a resistance to shear.

Numerical experiments: We theoretically consider an idealized system of many liquid bridges confined between two solid surfaces. By numerically calculating the shape of a single bridge, the total adhesion force is found as the number of bridges and roughness are varied. The resistance to shear is also calculated in the limit of strong surface tension or small shears.

Findings: Bridge splitting on a rough surface significantly enhances the adhesion force, with an enhancement that increases with the amplitude of the roughness; maximising over the number of bridges can increase the total adhesion force by an order of magnitude. Resistance to shear is shown to increase linearly with the translation velocity, and the behaviour of many such shearing bridges is quantified.
Original languageEnglish
Pages (from-to)514-529
Number of pages16
JournalJournal of Colloid and Interface Science
Volume607
Issue numberPart 1
Early online date28 Aug 2021
DOIs
Publication statusE-pub ahead of print - 28 Aug 2021

Keywords

  • Capillary adhesion
  • Roughness
  • Shear resistance
  • Surface tension

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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