Locally Resolved Analysis of Polymer Surface Functionalization by an Atmospheric Pressure Argon Microplasma Jet with Air Entrainment

Local analysis was performed of the chemical modification of polymeric surfaces induced by an atmospheric pressure microplasma jet operated with argon and small additions of air (1%). In particular, radial profiles were determined of water contact angle measurements and of the chemical surface composition using X-ray photoelectron spectroscopy. Special emphasis was given to the effects of air entrainment. Contact angle profiles significantly vary with treatment time. For longer treatment, the narrow primary profiles are superimposed by much wider secondary profiles of different shapes. That indicates the existence of different modification mechanisms. One possible reason for that is additional oxygen admixture to the radial afterglow. According to the analysis of nitrogen incorporation, substantial radial variations are found for the portion of gas phase oxygen and alkyl surface radicals, respectively.