Abstract
Polypyrrole films were deposited on platinum and tantalum and used as electrodes. The results indicate that these films are porous to solvent and electrolyte ions, and this porosity is responsible for the apparent reversible electrochemical behavior previously observed with many redox couples at polypyrrole on Pt. These electrochemically conducting films do exhibit electron transfer reactions with solution species, although less reversibly than at naked or film‐covered Pt. The films are unstable to oxidative conditions such as potentials > 0.6V vs. SCE or the presence of halogens.