Surface modification of polytetrafluoroethylene using atmospheric pressure plasma jet for medical application

Polytetrafluoroethylene (PTFE) is extensively utilized in medical devices and synthetic vascular surgery as an expanded form because of its chemical and mechanical stability. However, clinical applications in small diameter vascular grafts were limited due to lack of its haemocompatibility. In order to improve haemocompatibility or tailor the biological responses to the implant, the surface modification of PTFE was performed with two steps of treatment. After treating PTFE films in a solution of anthraguinone and sodium hydride in dry 100 °C dimethylformamide, the additional modification was performed with O2 atmospheric pressure plasma jet. The water contact angle of chemically treated PTFE was measured as 70.1°. Plasma treatment for 0.25 s decreased contact angle to 35.8°. From the analyses of XPS, plasma treatment might break down the unsaturated carbon bonds and introduce additional functional groups on the surface of the chemically modified PTFE. However, as the treatment time increased, contact angle increased and surface structure was changed, presumably due to etching of the chemical treated layer by oxygen plasma.