Recently, we published some X-ray absorption studies
where the potential of this method in surface chemical
analysis of polymers was successfully demonstrated. They
were summarized in Ref. t. In detail, we have shown that
one may differentiate between partially crystalline and
amorphous states at the surface of poly(ethylene terephthalate),.
The chemical and conformational response of
preferentially oriented polymer surfaces to oxygen plasma
treatments was investigated with poly(propylene) and
poly(ethylene terephthalate) 34. Moreover, the chemical
and structural effects of a chromium metallization on the
surface chemistry of poly(ethylene terephthalate) and
poly(bisphenol-A-carbonate) could be studied to some
extent 4' .
5"
In this communication the degradation phenomena,
occurring at the surface of aromatic polymers, which are
the result of oxygen DC plasma treatments are analysed,
again using Near Edge X-ray Absorption Fine Structure
(NEXAFS) spectroscopy 6. As is known, plasma treatment is
one approach to improve the surface properties of pol~,mers
with respect to adhesion of metals or polymers, etc.. The
whole matter is, of course, also of technological importance.
Interesting questions are to what extent an oxygen plasma
treatment degrades the polymer surface and how to analyse
it. We found NEXAFS spectroscopy to be an instructive
tool for monitoring effects due to plasma treatment.
* To whom correspondence should be addressed
Phenyl rings are often building units of technologically
relevant polymers. Concerning the "fate' of these phenyl
rings in the course of an oxygen plasma treatment it is well
known that, even when using the most advanced XPS
instrumentation s. it is a very difficult task to extract the
phenyl ring sub peak from the C 1 s XP spectra in a reliable
manner. Because in NEXAFS spectroscopy the C 1 s ---,
r*phenyl ring resonance is one of the most prominent
spectral features this special issue is exploited in this study
to monitor the effects of plasma treatment. Once again,
NEXAFS spectroscopy is proved to be a powerful extension
to XPS in surface chemical analysis of polymers.