MODIFICATION OF VARIOUS POLYMER SURFACES USING ATMOSPHERIC PRESSURE REDUCING PLASMA

This paper presents the results of surface modification of polymers induced by atmospheric pressure non-isothermal plasma generated in reducing atmosphere. The technology based on diffuse coplanar surface barrier discharge (DCSBD) was used with the aim to achieve highly hydrophobic surfaces. One rigid (polymethylmethacrylate-PMMA) and three flexible polymers (PMMA, polytetrafluoroethylene-PTFE and polyethylene terephthalate-PET) were modified by plasma. The changes in wetting phenomena and surface free energy were observed depending on plasma treatment conditions. The most significant modification occurred on flexible PMMA and PTFE. Using pure hydrogen plasma, we were able to achieve an increase of water contact angle up to similar to 115 degrees from the original value 78 degrees (untreated PMMA). On the contrary, the water contact angle on PTFE decreased to similar to 91 degrees from the value 109 degrees (untreated PTFE). Observed etching process on polymer surfaces and the changes in surface roughness were detected by a scanning electron microscopy (SEM) and atomic force microscopy (AFM).