PTFE surface modification by Ar plasma and its characterization

Polytetrafluoroethylene (PTFE) samples were exposed to argon plasma discharge and the changes of the PTFE surface properties were studied by different methods. Surface wettability and aging of the plasma modified PTFE were derived from the contact angle measured by standard goniometry. Electrokinetical potential (ζ-potential) was determined by SurPASS Instrument. The ζ-potential and the contact angle characterize “chemistry” of the PTFE surface and also make possible to follow the aging of the PTFE surface after the plasma treatment. The surface morphology and roughness were examined by Atomic Force Microscopy (AFM). Surface concentrations of elements were determined by X-ray photoelectron spectroscopy (ARXPS). The contact angle of the modified PTFE decreases with increasing time of the plasma treatment. During the aging of the plasma modified PTFE the contact angle increases. After the plasma treatment dramatic changes in the PTFE surface morphology and roughness were observed. Also a significant increase of ζ-potential is observed, which indicates more hydrophilic surface of the modified PTFE in comparison with pristine one. With increasing time of the plasma treatment the total oxygen content in the polymer surface layer increases.