Synthesis and texturization processes of (super)-hydrophobic fluorinated surfaces by atmospheric plasma

TL;DR

This study explores atmospheric plasma techniques to synthesize and texturize fluorinated surfaces, achieving super-hydrophobic properties through surface modification, fluorinated coatings, and nanoparticle incorporation, with plasma gas composition being a key factor.

Contribution

It presents an integrated analysis of plasma processes for creating super-hydrophobic fluorinated surfaces, highlighting the role of plasma gas and surface texturization methods.

Findings

Pure helium plasma enhances surface etching.

Adding O2 to plasma enables surface texturization.

Nanoparticle deposition achieves super-hydrophobicity with water contact angles over 150°.

Abstract

The synthesis and texturization processes of fluorinated surfaces by means of atmospheric plasma are investigated and presented through an integrated study of both the plasma phase and the resulting material surface. Three methods enhancing the surface hydrophobicity up to the production of super-hydrophobic surfaces are evaluated: (i) the modification of a polytetrafluoroethylene (PTFE) surface, (ii) the plasma deposition of fluorinated coatings and (iii) the incorporation of nanoparticles into those fluorinated films. In all the approaches, the nature of the plasma gas appears to be a crucial parameter for the desired property. Although a higher etching of the PTFE surface can be obtained with a pure helium plasma, the texturization can only be created if O2 is added to the plasma, which simultaneously decreases the total etching. The deposition of CxFy films by a dielectric barrier discharge leads to hydrophobic coatings with water contact angles (WCAs) of 115{\textdegree}, but only the filamentary argon discharge induces higher WCAs. Finally, nanoparticles were deposited under the fluorinated layer to increase the surface roughness and therefore produce super-hydrophobic hybrid coatings characterized by the nonadherence of the water droplet at the surface.