Superoleophobic Surfaces Obtained via Hierarchical Metallic Meshes

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Developing surfaces with both water and oil repellence is crucial for advanced applications.
• Hierarchical surface structures can enhance wetting properties by trapping air.
• Surface fluorination is a common method to achieve low surface energy and repellency.

Purpose of the Study:

• To engineer hierarchical metallic surfaces with superhydrophobic and superoleophobic properties.
• To investigate the relationship between surface topography, fluorination, and repellence.
• To assess the stability of the air trapping state on these engineered surfaces.

Main Methods:

• Fabrication of stainless-steel microporous meshes.
• Etching the meshes with perfluorononanoic acid to create hierarchical roughness.
• Characterization of surface topography at micro- and sub-microscales.
• Contact angle and sliding angle measurements with various liquids (water, ethanol solutions, oils).

Main Results:

• Successfully created hierarchical metallic surfaces with micro- and sub-microscale roughness.
• Demonstrated pronounced superoleophobicity against various oils (canola, castor, sesame, flax, crude, engine).
• Observed high sliding angles for specific oil droplets (turpentine, olive, silicone).
• Confirmed the stability of the Cassie-like air trapping wetting state with water/ethanol solutions.

Conclusions:

• The combination of hierarchical surface relief and fluorination leads to omniphobic behavior.
• The engineered surfaces exhibit robust water and oil repellence due to stable air trapping.
• These findings offer potential for developing advanced anti-fouling and self-cleaning materials.