Redox processes in thick films of polypyrrole/dodecylsulfate in the presence of alkali and tetramethylammonium chlorides

A complete understanding of the mechanism of charge transport in conducting polymers is essential to the design and optimization of these materials. In this work we present a systematic study of the redox behavior of thick polypyrrole/dodecylsulfate films in aqueous solutions of alkali and tetramethylammonium chlorides. The results suggest that under these experimental conditions alkali cations retain most of their solvation shell when entering the polymer. The transformation of the redox state starts from the solution side of the polymer and moves towards the electrode. The size of the hydrated cation determines whether the counter ions move as a uniform conductive front or whether they prefer moving through some pores in the polymer. The polymer was found to be irreversibly altered after the first redox cycle.