A study of atmospheric pressure plasma discharges for surface functionalization of PTFE used in biomedical applications

Plasma polymer surface modification is widely used in the biomedical field to tailor the surface properties of materials to improve their biocompatibility. Most of these treatments are performed using low pressure plasma systems but recently, filamentary dielectric barrier discharge (FDBD) and atmospheric pressure glow discharge (APGD) have appeared as interesting alternatives. The aim of this paper is to evaluate the potential of surface modifications realized with FDBD and APGD in different atmospheres (N(2)+ H(2) and N(2)+ NH(3) mixtures) on poly(tetrafluoroethylene) to determine the relative influence of both the discharge regime and the gas nature on the surface transformations. From XPS analysis, it is shown that the discharge regime can have a significant effect on the surface transformation; FDBDs operating in H(2)/N(2) lead to a high concentration of amino-groups with high specificity but also important damaging on the surface. Glow discharges in both H(2)/N(2) and NH(3)/N(2) lead to lower concentrations of amino-groups with lower specificity but lower surface damaging. Therefore, this simple surface treatment seems to be an effective, low cost method for the production of uniform surface modification with amino-groups that can subsequently be used to graft various chemical functionalities used for biomaterial compatibility.