Molecular orientation in cold-stretched poly(phenylene vinylene) films

Oriented poly(phenylene vinylene) (PPV) films were prepared by pre-stretching sulfonium precursors in methyl alcohol at room temperature and annealing these at 180°C. X-ray diffraction measurements show that the chain alignment and crystallinity in such PPV films increase with draw ratio. Preliminary conductivity measurements of these samples doped with ClSO3H appear to exhibit a similar dependence. This method of cold stretching, however, induces molecular orientation to a lesser degree than the more common technique of hot stretching, implying that swelling the precursor material in a polar solvent does not allow rates of strain as high as those accessed by heating.