Superoleophobic behavior induced by nanofeatures on oleophilic surfaces

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Controlling surface wetting is crucial for technological applications requiring hydrophobic and oleophobic properties.
• Intrinsically oleophilic surfaces pose a challenge for achieving significant oil repellency.

Purpose of the Study:

• To investigate the conditions for achieving robust hydrophobic and oleophobic effects on intrinsically oleophilic surfaces.
• To explore the role of fractal nanostructure, created by ion track etching, in modifying wetting properties.

Main Methods:

• Investigated wetting properties using eight liquids with varying surface tensions (18-72 mN m⁻¹).
• Utilized fractal nanostructured surfaces fabricated via ion track etching.
• Analyzed contact angles and resistance to liquid impregnation.

Main Results:

• Rough surfaces systematically increased contact angles for all tested oils compared to flat surfaces.
• Nanostructuration induced oleophobic behavior for liquids with surface tension ≥ 25 mN m⁻¹.
• Liquids with surface tension < 25 mN m⁻¹ maintained an oleophilic character but showed enhanced contact angles, never reaching the Wenzel state.

Conclusions:

• Fractal nanostructuring is effective in enhancing surface repellency on oleophilic materials.
• Achieving superoleophobic behavior depends on both surface nanostructure and liquid surface tension.
• The observed resistance to impregnation suggests potential for advanced liquid-repellent applications.