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Droplet Impact on Asymmetric Hydrophobic Microstructures
Susumu Yada1, Ugis Lacis1, Wouter van der Wijngaart2
1FLOW Centre, Department of Engineering Mechanics, Royal Institute of Technology (KTH), 100 44 Stockholm, Sweden.
Langmuir : the ACS Journal of Surfaces and Colloids
|June 23, 2022
Summary
Hydrophobic surfaces with inclined micropillars enable directional droplet rebound at high impact speeds. This directional rebound is due to asymmetric wetting behavior on the microstructures, controlling droplet mobility.
Area of Science:
- Surface science
- Fluid dynamics
- Materials science
Background:
- Nature-inspired hydrophobic surfaces, like butterfly wings, repel droplets unidirectionally.
- These surfaces are crucial for self-cleaning and anti-icing technologies.
- Understanding droplet impact on microstructures is key for advanced surface design.
Purpose of the Study:
- Investigate droplet impact dynamics on surfaces with inclined micropillars.
- Determine the influence of impact speed and microgeometry on rebound directionality.
- Elucidate the mechanisms behind directional rebound.
Main Methods:
- High-speed camera observation of droplet impacts.
- Fabrication of surfaces with inclined micropillars.
- Numerical simulations of droplet-surface interactions.
Main Results:
- Directional rebound observed at high impact speeds on dense micropillar arrays.
- Asymmetric wetting behavior and contact line retraction explain rebound directionality.
- Simulations provided detailed insights into droplet movement over microstructures.
Conclusions:
- Inclined micropillars effectively control droplet rebound directionality.
- Understanding wetting asymmetry is crucial for designing droplet-repellent surfaces.
- Findings aid in developing structured surfaces for targeted droplet mobility control.
