Publication details
Surface modification of PTFE by atmospheric pressure plasma
| Authors | |
|---|---|
| Year of publication | 2021 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Polytetrafluoroethylene (PTFE) is widely used in the engineering field because of its excellent mechanical and chemical properties. However, the lower wettability and poor adhesion greatly limit the application of PTFE, especially in biological field. Researchers are exploring various physical and chemical methods to modify the surface of PTFE to improve these disadvantages. The atmospheric pressure plasma has always been the main force in the field of surface modification due to its unique characteristics [1,2]. The main objective of this work is to modify the surface of the PTFE by Diffuse Coplanar Surface Barrier Discharge (DCSBD) and Multi-hollow Dielectric Barrier Discharge (MHDBD). The PTFE foils were treated by the low-temperature non-equilibrium DCSBD and MHDBD plasma generated in ambient air, oxygen, the mixture of H2/N2 (5% volume content of H2), and argon plasma (only DCSBD). In this work we focused on using standard “safe” gases that requires no special treatment/manipulation and thus we significantly expand the results that have been previously reported for DCSBD plasma modification of PTFE in pure hydrogen plasma [3]. The wettability and aging behavior were measured using See system. The surface chemistry is investigated by X-ray photoelectron spectroscopy (XPS). The results show that the wettability of PTFE can be effectively improved by DCSBD and MHDBD plasma. The mixture of H2/N2 plasma was the most effective gas to improve the wettability of PTFE with DCSBD. The plasma-treated PTFE samples, stored in the air for a long time, exhibited only a partial recovery of original WCA values. Furthermore, plasma-treated PTFE tubes were tested for improvement of its adhesion properties. We observed that the plasma can effectively improve the adhesion of glue joints of the PTFE tubes. Using the MHDBD plasma, we studied the modification of thin PTFE foils and the effects of different experimental parameters, such as power input, working gas flow rate, PTFE foil surface to plasma unit surface gap size. The results show that wettability improvement effect is basically the same when the distance between the PTFE foil and the ceramic surface is in the range 0.1-1 mm. It means that MHDBD can modify slight curved and uneven surfaces to same extent. The XPS analysis show that DCSBD and MHDBD plasma treatment of PTFE results in an increase of oxygen and carbon concentration, decrease of fluorine concentration and changes in presence of polar functional groups. The results of wettability changes of plasma-treated PTFE together with the XPS analysis thus support the observed adhesion improvement of plasma-treated PTFE. |