Study of plasma modified-PTFE for biological applications: relationship between protein resistant properties, plasma treatment, surface composition and surface roughness.

PTFE samples were treated by low-pressure, O2 RF plasmas. The adsorption of BSA was used as a probe for the protein resistant properties. The exposure of PTFE to an O2 plasma leads to an increase in the chamber pressure. OES reveals the presence of CO, CO2 and F in the gas phase, indicating a strong etching of the PTFE surface by the O2 plasma. Furthermore, the high resolution C1s spectrum shows the appearance of CF3, CF and C-CF components in addition to the CF2 component, which is consistent with etching of the PTFE surface. WCA as high as 160° were observed, indicating a superhydrophobic behaviour. AFM Images of surfaces treated at high plasma power showed a increase in roughness. Lower amounts of BSA adsorption were detected on high power, O2 plasma-modified PTFE samples compared to low power, oxygen plasma-modified ones.