Rationally designed surface microstructural features for enhanced droplet jumping and anti-frosting performance

Area of Science:

• Materials Science
• Surface Engineering
• Heat Transfer

Background:

• Frost accretion on heat exchangers reduces efficiency in cold environments.
• Droplet jumping from micro/nanostructured surfaces is a key anti-frosting strategy.
• Understanding microstructural effects on droplet jumping is crucial for optimization.

Purpose of the Study:

• Investigate the relationship between micro-cone array features and water droplet removal.
• Optimize surface structures for enhanced anti-frosting performance.
• Clarify the transition from partial wetting to Cassie state for efficient water removal.

Main Methods:

• Fabrication of aluminum surfaces with varied micro-cone arrays using laser processing and etching.
• Statistical analysis of condensation processes to evaluate water removal.
• Condensation experiments measuring water removal rates over time.

Main Results:

• Enhanced water removal from 3.42 g m⁻² to 13.91 g m⁻² with optimized micro-cone sizes (10-40 μm).
• Achieved transition from high-adhesion partial wetting to low-adhesion Cassie state.
• Optimal structures showed minimal water accumulation and over 90 minutes of frosting delay.

Conclusions:

• Microstructure size critically influences droplet jumping and water removal efficiency.
• Optimized micro-cone structures provide superior anti-frosting capabilities.
• This research offers a pathway for designing advanced anti-frosting surfaces.