MORPHOLOGY OF A CONDUCTING POLYMER AND ITS RELATION TO THE ELECTRONIC-PROPERTIES

We have investigated the morphology of a heavily disordered conducting polymer, polypyrrole doped with large polymeric anions. An extensive microscopy study (scanning electron microscopy, atomic force microscop y and transmission electron microscopy) together with previously obtai ned information on the samples' electronic properties conveys to us th e following image: the observed globules of diameters between 10 and 1 00 nm originate from the polymeric dopants forming coils with the dopi ng centers concentrated on the coil surfaces and the polypyrrole surro unding the whole. In this way polypyrrole-rich ''sheets'' run through the whole sample and guarantee the electrical continuity which prevail s even in samples with polypyrrole volume fractions as low as several per cent. For the first lime, the building block of the ''fractal'' ca uliflower structure, observed also in many other electrochemically pre pared conducting polymers, could be identified.