Plasma surface modification of polymeric materials present many advantages over other treatment methods, such as wet chemical treatments and mechanical roughening, due to the versatility of the processes, effectiveness of treatments, and environmentally benign nature of plasma processes. However, plasma processes have significant drawbacks for polymer surface treatment, mainly due to the uncontrollable nature of the plasma, which contains many reactive species including electrons, excited neutral species, free radicals, vacuum ultraviolet (VUV) and ultraviolet (UV) photons, and ions. This complex nature of plasma prevents the optimization of certain desirable reactions and the minimization of undesired consequences, such as surface degradation

Recent advancements in our research center have demonstrated the many unique advantages of a low pressure plasma discharge process, low temperature cascade arc torch (LTCAT), over traditional plasma techniques, including significant reduction of damage on polymer surfaces and enhanced surface stability. In addition, LTCAT treatment is fast and effective, in the case of Ar LTCAT, 2 s exposure time was reported as the optimum treatment time for the surface modification of low density polyethylene (LDPE). In this study, LTCAT of argon with or without adding reactive gas of oxygen or water vapor was used to treat LDPE. Surface contact angle measurements using static sessile droplet method and dynamic Wilhelmy balance method were employed to investigate and characterize LTCAT treatment effects. These treatment effects include surface wettability changes, surface stability, and possible surface damages that will create low molecular weight oligomers on the treated surface. Optical emission spectroscopy was used to monitor the photo-emitting species in LTCAT. The detailed experimental data obtained in this study will be presented and discussed in the meeting.