An investigation of the surface chemical homogeneity of plasma oxidised poly(ether etherketone)

Time of flight secondary ion mass spectrometry (ToF-SIMS) has been used to probe the lateral surface chemical homogeneity of plasma-oxidised poly(ether etherketone) (PEEK). A simple numerical normalisation procedure has been used to enable the comparison of peak intensities between spectra. The results reported show a high level of spectral reproducibility in the analyses of an unoxidised PEEK film. However, when the normalisation procedure was used to analyse the SIMS data obtained from adjacent areas of a plasma-oxidised PEEK film a much greater variation in the normalised peak intensities was observed. The author argues that the latter arises because plasma-oxidation does not produce a chemically homogeneous modification in, at least, the outermost 1 mn of this polymer. Physical changes occurring in the surface of PEEK with plasma oxidation were revealed by scanning electron microscopy (SEM).