Adhesion improvement of large area flexible PTFE foils by atmospheric pressure plasma
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| Year of publication | 2022 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Polytetrafluoroethylene (Teflon, PTFE) as an indispensable polymer has been widely used in modern society because of its excellent physical and chemical bulk properties. However, due to its low surface and weak boundary layer, the surface wettability and adhesion properties of PTFE are poor. This greatly limits the application of PTFE in the field with higher demand for the adhesion and wettability, especially in the biomedicine area. Therefore, it is very important to improve the adhesion and wettability of the PTFE surface. Nowadays, environmental protection and high efficiency are urgent needs in the industry. Plasma is the preferred option to satisfy those requirements [1,2]. The main objective of this work is to rapidly modify the surface of large area flexible PTFE foils by Diffuse Coplanar Surface Barrier Discharge (DCSBD) in order to improve the adhesion and wettability. The flexible PTFE foils were treated by the low-temperature non- equilibrium DCSBD plasma generated in ambient air, Argon and the mixture of H2/N2 (5% volume content of H2). The plasma modification of PTFE foils was done in a special closed roll-to-roll device that enables in-line plasma treatment of flexible substrates up to the width of ~ 200 mm. The adhesion test of the flexible PTFE foils was performed by 90 degree peel adhesion test. The wettability and aging behavior were assessed by water contact measurement of sessile droplets. The surface chemistry and roughness were investigated by X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM). It can be found that the adhesion and wettability of the flexible PTFE foils can be effectively improved by DCSBD plasma, however a significant effect of used working gas was observed. The mixture of H2/N2 seems to be as the most effective gas for modification of PTFE. The oxygen-containing functional group are introduced to the surface of the flexible PTFE foils after plasma treatment and the surface roughness of plasma-treated flexible PTFE foils also increases. The results of the aging behavior show the plasma-treated flexible PTFE foils exhibited only a partial recovery of the original wettability after two weeks. |
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