Blends were obtained by impregnation of an insulating polymer matrix,
poly(vinyl chloride), with an oxidant, FeCl3, followed by exposure to
pyrrole vapor. The redox properties of films of the blends obtained by
this method were studied by cyclic voltammetry and impedance spectros
copy. The results show that thin films (20 mum) are more electroactive
than thick films (100 mum) although the proportion of polypyrrole is
the same for both (ca. 38%). This electroactive behavior is in agreeme
nt with morphology observations, which show different phase separation
mechanisms as a function of the film thickness: a spinodal mechanism
for the thin film and a binodal mechanism for the thick film.