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Updated: Jul 17, 2026

Fabrication of Superhydrophobic Metal Surfaces for Anti-Icing Applications
Published on: August 15, 2018
Contact line shape on ultrahydrophobic post surfaces
Christian Dorrer1, Jürgen Rühe
1Laboratory for the Chemistry and Physics of Interfaces, Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 103, D-79110 Freiburg, Germany.
Water drops on ultrahydrophobic surfaces exhibit highly distorted contact lines. This distortion impacts contact angle measurements on these advanced materials.
Area of Science:
- Physics
- Materials Science
- Fluid Dynamics
Background:
- Ultrahydrophobic surfaces exhibit unique wetting properties.
- Understanding the behavior of liquids on these surfaces is crucial for various applications.
- The Cassie wetting state describes a specific liquid-solid interaction on composite surfaces.
Purpose of the Study:
- To investigate the configuration of a water drop's contact line on an ultrahydrophobic post surface.
- To propose a modified definition for the contact line in the Cassie wetting state.
- To analyze the impact of contact line distortion on contact angle measurements.
Main Methods:
- Numerical simulations using the Surface Evolver algorithm.
- Analysis of the liquid-air interface deformation.
- Investigation of contact line configuration.
Main Results:
- The contact line is found to be strongly distorted on ultrahydrophobic surfaces.
- A tendency for the water drop to "ball up" is observed where it does not contact the solid.
- The liquid-air interface shows pronounced deformation around the drop's base.
Conclusions:
- The study provides a new definition for the contact line in Cassie wetting.
- Contact line distortion significantly affects the interpretation of contact angle measurements.
- Findings are critical for accurate characterization of ultrahydrophobic materials.
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