New phenomena observed during the electrochemical reduction of conducting polypyrrole films

Properties of polypyrrole/dodecyl sulfate films were studied by different s pectro electrochemical, ex. situ alternating current conductance and IR tec hniques. It was demonstrated that the open-circuit time after the accomplis hment of the electropolymerisation has a key role in the redox behaviour of the film. Layers reduced immediately after the deposition exhibit differen t charge capacity, conductance and reducibility: once the film was reduced in this manner, it could be transformed into either the totally neutral or the quasimetallic state anymore. The pristine film can reach the quasimetal lic state only after a certain period of time at open circuit. The reductio n of this film can be interpreted by a dissociation-type first step, instea d of the classical consecutive two-step mechanism.