Positive Ion Mass Spectrometry during an Atmospheric Pressure Plasma Treatment of Polymers

A low power atmospheric pressure helium plasma torch was used to modify the surface chemistry of poly( α ‐methylstyrene), polystyrene, poly(propylene) and polyethylene. Mass spectra of the positive ions present in the plasma during the treatment revealed dominant ions with structures that reflected the structure of the polymer, e.g. C 6 H 5 C n H 2 n containing a phenyl group in the aromatic polymers and hydrocarbon structures C n H 2 n ± 1 up to n = 14 for poly(propylene). Ions up to m / z 300 were detected. X‐ray photoelectron spectroscopy showed that this treatment introduced oxygen‐containing functional groups into the surface of the polymers. magnified image