XPS and transport studies of PVA-PPy and Pth-PST composites

Summary form only given. Polypyrrole-(polyvinyl alcohol- FeCl/sub 3/ or CuCl/sub 2/) and polythiophene-polystyrene-(FeCI/sub 3/) conducting polymer composites have been synthezised above the percolation threshold. Compounds reach conductivity as high as 5 S/cm and 2 S/cm respectively, at RT. In the temperature range 80-300 K, d.c. electrical conductivity is weakly activated while thermoelectrical power variations are quasi linear. A major contribution of bi-polaronic hopping between the polymeric chains is shown to take account for all these experimental results. Conductivity measurements extended from 4K to 300K are compared to those recorded for PPy powders doped at different levels. All results will be discussed in view of the existing theoretical models. The stability of the samples stored in ambiant atmosphere has then been studied by microprobe analysis, X-ray photoelectron spectroscopy (XPS) and conductivity. In the case of PPy -PVA composite, it is observed that the atomic percentage of oxygen increases with time. The existence of a Cl motion towards the surface of the film followed by a release from the composite has been put in evidence. It is shown that the N 1s high binding energy component can be attributed to positvely charged nitrogen induced by doping.