Improving superamphiphobicity by mimicking tree-branch topography.

Area of Science:

• Surface Science
• Fluid Dynamics
• Materials Science

Background:

• Superhydrophobic surfaces repel water droplets, but their effectiveness decreases with low surface tension liquids.
• Existing superamphiphobic surfaces struggle to maintain non-wetting properties when impacted by low surface tension fluids.
• Understanding droplet-surface interactions is crucial for developing advanced anti-wetting materials.

Purpose of the Study:

• To investigate the anti-wetting performance of novel superamphiphobic surfaces against low surface tension droplets.
• To explore the potential of multi-layer re-entrant structures in enhancing surface non-wetting properties.
• To elucidate the droplet impact mechanism on surfaces with hierarchical roughness.

Main Methods:

• Fabrication of patterned conical micro-structures with lateral nano-sized roughness.
• Conducting droplet impact experiments using liquids with varying surface tensions (27-72 mN/m).
• Analyzing droplet behavior across a range of Weber numbers (2-170).

Main Results:

• Conical microstructures with tree-branch-like nano-roughness effectively prevent droplet pinning.
• The designed surface topology absorbs impact forces, enabling droplet bouncing at higher velocities.
• Enhanced anti-wetting performance was observed even for low surface tension fluids.

Conclusions:

• Hierarchical surface structures are key to repelling low surface tension droplets.
• The developed superamphiphobic surface design offers superior performance in droplet impact scenarios.
• This research provides insights for designing advanced surfaces with robust anti-wetting capabilities.