XPS and transport studies of PVA-PPy and PSt-PBTh composites

The properties of polypyrrole powder, polypyrrole poly(vinylalcohol) composite and polythiophene-polystyrene composite chemically polymerized and doped with the same oxidant FeCl3 have been studied by X-ray photoelectron spectroscopy (XPS) and measurements of the electrical conductivity. At RT, the two composites reach conductivity as high as 5 S/cm and 2 S/cm, respectively. The observed transport properties are characteristic for the hopping between bipolaronic cluster as the dominantly contributing mechanism. The existence of a Cl motion towards the surface of the film followed by a release from the composite has been put in evidence by XPS analysis which can explain the electrical instability observed for both composites.