Hierarchically structured superoleophobic surfaces with ultralow contact angle hysteresis

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Superoleophobic surfaces repel oil-based liquids.
• Low contact angle hysteresis is crucial for efficient liquid droplet manipulation.
• Achieving low hysteresis with low-surface-tension liquids remains a challenge.

Purpose of the Study:

• To develop hierarchically structured surfaces with superoleophobic properties.
• To achieve ultra-low contact angle hysteresis for low-surface-tension liquids.
• To demonstrate droplet bouncing and roll-off capabilities at minimal tilt angles.

Main Methods:

• Fabrication of hierarchically structured surfaces.
• Characterization of surface wettability using various liquids, including n-heptane.
• Measurement of contact angle and contact angle hysteresis.

Main Results:

• Demonstrated hierarchically structured, superoleophobic surfaces.
• Achieved ultra-low contact angle hysteresis values, among the lowest reported.
• Successfully enabled ≈2 μL n-heptane droplets to bounce and roll-off at tilt angles ≤ 2°.

Conclusions:

• Hierarchically structured surfaces can effectively achieve superoleophobicity with minimal hysteresis.
• These surfaces represent a significant advancement in controlling low-surface-tension liquid droplets.
• Potential applications in self-cleaning, anti-fouling, and microfluidic devices.