Related Experiment Video
Updated: Jun 25, 2026
Rendering SiO2/Si Surfaces Omniphobic by Carving Gas-Entrapping Microtextures Comprising Reentrant and Doubly Reentrant Cavities or Pillars
Published on: February 11, 2020
Asymmetric wetting hysteresis on hydrophobic microstructured surfaces
Craig Priest1, Trent W J Albrecht, Rossen Sedev
1Ian Wark Research Institute, ARC Special Research Centre for Particle and Material Interfaces, University of South Australia, Mawson Lakes, South Australia 5095, Australia. craig.priest@unisa.edu.au
Investigating hydrophobic microstructured surfaces, this study reveals that liquid wetting depends on solid continuity. Distinct wetting hysteresis patterns were observed for pillar and hole arrays, with trends linked to area fraction.
Area of Science:
- Surface Science
- Materials Science
- Fluid Dynamics
Background:
- Understanding surface wettability is crucial for various applications.
- Hydrophobic surfaces with microstructures offer tunable wetting properties.
- The Cassie state describes liquid behavior on such textured surfaces.
Purpose of the Study:
- To investigate the wetting behavior of hydrophobic microstructured surfaces.
- To analyze the influence of feature separation (area fraction) on wettability.
- To compare wetting hysteresis on pillar versus hole microstructures.
Main Methods:
- Fabrication of microstructured surfaces with fixed feature size (20 microm) and varied separation.
- Controlled adjustment of the solid area fraction from 0% to 80%.
- Measurement and analysis of contact angle hysteresis for different microstructures.
Main Results:
- Wettability in the Cassie state strongly depends on the continuity of the solid component.
- Microstructured square pillars and holes exhibited distinct, asymmetric wetting hysteresis.
- Clear trends were observed for contact angle hysteresis magnitude versus area fraction for both pillar and hole surfaces.
Conclusions:
- The continuity of the solid phase is a critical factor governing wetting on microstructured hydrophobic surfaces.
- Wetting hysteresis is asymmetric and differs significantly between pillar and hole arrays.
- The study provides insights into pinning energy associated with microstructured surfaces.
