Electropolymerization: Further insight into the formation of conducting polyindole thin films

(Chemical Equation Presented). Electropolymerization is a promising route to design new functional surfaces. In this work, we investigate electropolymerization of indole at polycrystalline Pt electrode surfaces in acidic sulfuric media using in situ nanogravimetry, electrochemical impedance spectroscopy, and direct current (dc) measurements applied simultaneously to elucidate the physical model of the electrified interface during this process. Monitoring the electrode mass change with a quartz crystal nanobalance allows quantification of the overall electropolymerization kinetics and, together with the dc-response, provides further insight into the dynamics of the film formation. Complementary electrochemical impedance spectroscopy measurements quantify specific parameters characterizing the processes which involve the interfacial charge transfer during the fi lm growth. Importantly for various applications, it has been also demonstrated that the growth of polyindole thin films can be controlled using just molecular oxygen dissolved in the electrolytes.