Effect of Atmospheric Cold Plasma Treatment on the Adhesion and Tribological Properties of Polyamide 66 and Poly(Tetrafluoroethylene)

Abstract

The surfaces of two engineering polymers including polyamide 66 (PA66) and polytetrafluoroethylene (PTFE) were treated by diffuse coplanar surface barrier discharges in atmospheric air. We found that plasma treatment improved the adhesion of PA66 for either polymer/polymer or polymer/steel joints, however, it was selective for the investigated adhesive agents. For PTFE the adhesion was unaltered for plasma treatment regardless the type of used adhesive. Tribological properties were slightly improved for PA66, too. Both the friction coefficient and wear decreased. Significant changes, again, could not be detected for PTFE. The occurred variation in the adhesion and tribology was discussed on the basis of the occurred changes in surface chemistry, wettability and topography of the polymer surface.

Recent Advances in Surface Activation of Polytetrafluoroethylene (PTFE) by Gaseous Plasma Treatments

“…The moderately hydrophilic character of PTFE after plasma treatments was also reported by Karoly et al [ 28 ]; however, they used a completely different discharge than previously cited authors. Plasma was sustained by a high-impedance coplanar atmospheric pressure discharge operating in air at the frequency of 10–20 kHz with a 20 kV peak-to-peak voltage and a power of 320 W. The treatment times were between 30 and 600 s. The original WCA, which was 108°, slowly decreased with increasing treatment time and dropped to about 65° after 600 s of treatment.…”

“…Interestingly, the increased wettability did not result in the better adhesion of various glues. The positive effect of the plasma treatment, as reported by Karoly et al [ 28 ], was a significant decrease in the standard deviation of the adhesive forces.…”

“…The deviation from the theoretical value was explained by the partial substitution of F from PTFE with O. Although Krumpolec et al used almost identical conditions as Karoly et al [ 28 ], no nitrogen was observed on the surface of PTFE after plasma treatment. Both authors used XPS for probing the surface composition.…”

Cold atmospheric pressure plasma: simple and efficient strategy for preparation of poly(2-oxazoline)-based coatings designed for biomedical applications

“…2a. Up to now, the treatment of PTFE by DCSBD plasma source was reported in few articles 37,38 , but the information about WCA changes was mentioned only by Károly et al 39 Here, the authors achieved a negligible decrease of WCA from initial 108° to 101° after 30 s of plasma treatment; however, their plasma setup parameters were slightly different. They used the longer distance between the sample and plasma source (0.5 mm) and lower input power (320 W) and these conditions were thus less efficient compared to our case.…”

Physicochemical Studies on the Surface of Polyamide 6.6 Fabrics Functionalized by DBD Plasmas Operated at Atmospheric and Sub-Atmospheric Pressures

“…As an alternative to the conventional chemical functionalization of fabrics, a treatment based on cold plasma, also called non-thermal plasma, emerged [ 14 , 15 , 16 , 17 , 18 , 19 ]. This dry method has the advantages of being environmentally friendly, worker friendly, operating at atmospheric or sub-atmospheric pressure, and can modify the surface of the textiles without affecting their bulk properties, in addition to being suitable for most heat-sensitive polymeric textile materials [ 20 , 21 , 22 , 23 , 24 ].…”