Experimental Evidence for the Dominance of vuv Photons in Remote Hydrogen Plasma Treatments

Abstract

AbstractThe flux of vacuum ultraviolet (VUV) and ultraviolet (UV) photons from a hydrogen plasma was detected by fluorescence measurements of sodium salicylate sheets with and without a MgF2 window. In order to expose the samples to the same photon flux in all experiments, the power input to the microwave plasma source was adjusted. Polyethylene (PE), polypropylene (PP), and polystyrene (PS) were treated with VUV radiation or with a remote hydrogen plasma. The mass loss and the CH-absorption loss were recorded by in situ quartz crystal micro balance and by in situ IR reflection absorption spectroscopy, respectively. The VUV irradiation and plasma treatment caused similar effects in the case of PE, PP showed an increased polymer ablation in plasma treatments, and for PS a negligible loss in mass and CH absorption was detected in plasma and VUV treatments.