PTFE surface etching in the post-discharge of a scanning RF plasma torch: Evidence of ejected fluorinated species

The texturization of poly(tetrafluoroethylene) (PTFE) surfaces is achieved at atmospheric pressure by using the post-discharge of a radio-frequency plasma torch supplied in helium and oxygen gases. The surface properties are characterized by contact angle measurement, X-ray photoelectron spectroscopy and atomic force microscopy. We show that the plasma treatment increases the surface hydrophobicity (with water contact angles increasing from 115 to 155°) only by modifying the PTFE surface morphology and not the stoichiometry. Measurements of sample mass losses correlated to the ejection of CF ₂ fragments from the PTFE surface evidenced an etching mechanism at atmospheric pressure. Poly(tetrafluoroethylene) (PTFE) surfaces have been texturized at atmospheric pressure by using the post-discharge of a radio-frequency plasma torch supplied in helium and oxygen gases. An etching mechanism of the surface has been highlighted by correlating the mass losses measurements to the ejection of CF ₂ fragments from the PTFE surface and to an increase in the surface hydrophobicity.