CONDUCTIVITY, MAGNETIC-SUSCEPTIBILITY AND NUCLEAR-RELAXATION, AS A FUNCTION OF AGING IN POLYPYRROLE

Stability of conducting polymers is of prime importance for their use in practical applications. In this work we report conductivity, ESR ex periments and relaxation time on aged polypyrrole powder, synthesized in water by FeCl3 oxidizing polymerization of pyrrole. Samples are hea ted to 140 degrees C to accelerate the ageing process. Results give ev idence for a linear relationship between RPE linewidth and diffusion c oefficient along the chains: due to the decrease of spin mobility as a function of ageing, the ESR linewidth broadening, attributed to stron g collisions between polarons against fixed iron paramagnetic center, decreases with time.