CHAIN ALIGNMENT IN POLY(P-PHENYLENE VINYLENE) ON ORIENTED SUBSTRATES

We show that conjugated polymers processed via soluble precursor polymers can be oriented by forming them on highly-oriented poly(tetrafluoroethylene), PTFE. The oriented PTFE induces preferential orientation of the precursor polymers which is preserved and possibly enhanced during the thermal conversion to the final conjugated polymer. Orientation is substantially better if precursor polymers are used which have a some content of stiff segments in their backbone. We characterise the state of alignment of the polymer by polarised optical absorption measurements. We consider that orientation is confined to a thin layer adjacent to the substrate, and find from the form of the interband absorption that the extent of conjugation is enhanced in this oriented region.