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A microscopic theory of small-droplet adhesion on solid surfaces
Ruize Yin1,2, Fei Wang1,2, Britta Nestler1,2,3
1Institute for Applied Materials-Microstructure Modelling and Simulation (IAM-MMS), Karlsruhe Institute of Technology (KIT), Strasse am Forum 7, 76131 Karlsruhe, Germany.
The Journal of Chemical Physics
|July 14, 2026
Summary
Researchers developed a new theory explaining droplet sliding on surfaces. Droplet adhesion is enhanced under negative loads, violating Amontons' first law, and the theory explains contact angle hysteresis.
Area of Science:
- Physics
- Materials Science
- Surface Science
Background:
- The microscopic origins of droplet sliding criteria and solid-liquid adhesion are not fully understood.
- Droplets resist lateral forces before sliding, but the underlying physics is elusive.
Purpose of the Study:
- To develop a microscopic theory for droplet sliding and adhesion on solid surfaces.
- To elucidate the microscopic origins of the sliding criterion and contact angle hysteresis.
Main Methods:
- Developed a microscopic mean-field theory incorporating solid-liquid interfacial energy dependence on droplet body energy.
- Mapped the energy landscape under coupled normal and lateral loads.
- Proposed a sliding criterion in the small-droplet limit.
Main Results:
- Identified a novel microscopic lubrication-like interfacial state.
- Proposed a sliding criterion where solid-liquid and solid-gas interfacial energies become equal.
- Explained enhanced adhesion under negative normal loads, violating Amontons' first law.
- Revealed the microscopic origin of pinning force and contact angle hysteresis.
Conclusions:
- The developed theory provides a consistent framework for understanding droplet adhesion and sliding.
- The theory quantitatively agrees with experimental observations across diverse conditions.
- The findings offer new insights into surface phenomena and droplet dynamics.
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