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Updated: Jun 14, 2026
Measuring the Interaction Force Between a Droplet and a Super-hydrophobic Substrate by the Optical Lever Method
Published on: June 14, 2019
Measurement of lateral adhesion forces at the interface between a liquid drop and a substrate
Rafael Tadmor1, Prashant Bahadur, Aisha Leh
1Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas 77710, USA.
Abstract:
A novel instrument allows for the first time measurements of the lateral adhesion forces at a solid-liquid interface, f(parallel), in a way that is decoupled from the normal forces, f(perpendicular). We use it to measure how f(parallel) between a drop and a surface is influenced by different f(perpendicular) and different histories of drop resting periods on the surface prior to sliding, t(rest). The variation of f(parallel) with t(rest) is similar for different f(perpendicular) and always plateaus as t(rest)-->infinity. We show that the f(parallel) plateau value is higher when f(perpendicular) is lower. This seemingly counterintuitive result is in agreement with recent theories.
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