THERMAL-CONVERSION OF POLY(PARA-PHENYLENE-VINYLENE) PRECURSOR FILMS -XPS AND ESR STUDIES

The conversion of the precursor into poly(phenylene-vinylene) (PPV) wa s studied by means of photoelectron spectroscopy (XPS) and electron sp in resonance (ESR) on precursor films synthesized from the polymerizat ion of pxylene-tetrahydrophenium halides. The sulfonium precursor cont aining chlorine or bromine was thermally converted to PPV and analyzed in situ using the spectrometers. It was found by XPS analysis that bo th halide precursors were thermally converted into polymer in a range of 190-250 degrees C but traces of bromine were still present at > 300 degrees C in the precursor containing Br. Furthermore, a small amount of oxygen in a ketone structure was also present in fully converted f ilms. The ESR results corroborated the XPS experiments, showing a prog ressive disappearance of the radical distribution related to sulfur si tes in a comparable temperature range. A discussion of the conversion process is given in terms of the modification of the core level spectr a from XPS and the g distributions from ESR experiments. (C) 1998 John Wiley & Sons, Ltd.