KINETICS OF THE POLYPYRROLE ELECTROGENERATION FROM AQUEOUS-SOLUTION - AN EXSITU MICROGRAVIMETRIC STUDY

Polypyrrole electrogeneration has been studied by microgravimetry, modifying electrolyte and monomer concentrations and temperature. The obtained empirical kinetics were: polymerization rate = k [pyrrole]0.6 [ClO4-]0.8. The high influence of the electrolyte was attributed to an addition of three factors: oxide generation, doping process, and electrolyte discharge. From the obtained polymer weights and the charges spent during polymerizations, polymerization current efficiencies between 4 x 10(-4) and 5 x 10(-4) (mg mC-1) were obtained. The number of electrons transferred by a monomeric unit was also calculated. Lower values than two were obtained under most of the experimental conditions. A model of interfacial reactions capable of explaining the experimental results is proposed.