A low power 50 Hz argon plasma for surface modification of polytetrafluoroethylene

The characteristics of a low power 50 Hz argon plasma for surface treatment of polytetrafluoroethylene (PTFE) film is presented in this article. The current-voltage behavior of the discharge and time-varying intensity of the discharge showed that a DC glow discharge was generated in reversed polarity at every half-cycle. At discharge power between 0.5 and 1 W, the measured electron temperature and density were 2-3 eV and similar to 10(8) cm(-3), respectively. The optical emission spectrum of the argon plasma showed presence of some 'impurity species' such as OH, N-2 and H, which presumably originated from the residual air in the discharge chamber. On exposure of PTFE films to the argon glow plasma at pressure 120 Pa and discharge power 0.5 to 1 W, the water contact angle reduced by 4% to 20% from the original 114 degrees at pristine condition, which confirms improvement of its surface wettability. The increase in wettability was attributed to incorporation of oxygen-containing functional groups on the treated surface and concomitant reduction in fluorine as revealed by the XPS analysis and increase in surface roughness analyzed from the atomic force micrographs. Ageing upon storage in ambient air showed retention of the induced increase in surface wettability.

Automated summary

This article presents the characteristics of a low power 50 Hz argon plasma used for surface treatment of polytetrafluoroethylene (PTFE) film. The experimental results show that under specific conditions, the argon glow plasma can improve the surface wettability of PTFE film, which is mainly attributed to the introduction of oxygen-containing functional groups on the treated surface and reduction in fluorine.