Valence band region XPS, AFM and NEXAFS surface analysis of low pressure d.c. oxygen plasma treated polypropylene
✍ Scribed by Th. Gross; A. Lippitz; W.E.S. Unger; J.F. Friedrich; Ch. Wöhll
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 443 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0032-3861
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✦ Synopsis
Biaxially stretched polypropylene (PP) foils treated with oxygen plasma at low pressure were analysed by core level and valence band region X-ray photoelectron spectroscopy (XPS), atomic force microscopy and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Applying short treatment times the XPS O~C atomic ratios are ~<0.1. Valence band electron spectroscopy for chemical analysis (ESCA) and NEXAFS spectroscopy reveal that a certain number of C-O and a smaller amount of C--O functionalities together with C=C bonds exist at a short-time treated PP surface. These species were not observed or resoh'ed by a standard core level XPS analysis of the same surface. The surface is smoothed by the plasma treatment and the C-O and C~O bonds are slightly non-statistically oriented (parallel to the surface plane). Considering the results obtained after prolonged plasma treatment, NEXAFS spectroscopy provides a direct indication for the formation of conjugated carbon double bonds in the surface region of the PP samples.