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Updated: Aug 23, 2025
Measuring the Interaction Force Between a Droplet and a Super-hydrophobic Substrate by the Optical Lever Method
Published on: June 14, 2019
How droplets move on laser-structured surfaces: Determination of droplet adhesion forces on nano- and microstructured
Georg Schnell1, Christian Polley1, Robert Thomas1
1Microfluidics, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Justus-von-Liebig Weg 6, 18059 Rostock, Germany.
Hypothesis:
Lateral adhesion forces are a fundamental property of liquid-solid interactions and a key aspect of dynamic droplet mobility. But, commonly applied conventional wetting analysis is limited to static and quasi-static methods and cannot resolve dynamic and spatial liquid-solid interactions. However, droplet mobility is assumed to be affected by chemical and topographic surface inhomogeneities introduced by femtosecond laser treatment.
Experiments:
In this study, we used a customized droplet adhesion force instrument to determine lateral adhesion forces on various femtosecond laser-structured surface designs to obtain a deeper understanding of the dynamic droplet motion with regard to chemical and topographic surface features.
Findings:
We show that the droplet motion was highly affected by the chemical and topographical surface design and local inhomogeneities. The droplet mobility on femtosecond laser-structured surfaces could be classified into a static, a transfer, and a kinetic regime, which is essential for designing surfaces with extreme wetting characteristics and a wide range of scientific and industrial processes. Furthermore, with proper tailoring of surface structures and chemical modification, we were able to provoke adhesion forces on self-organized laser microstructures similar to those found on the natural lotus leaves.
