Spectroelectrogravimetry of the electrical conductivity activation in poly(o-toluidine) films

The study of the first stages of the transformation of conducting films from the insulating to the conducting form by oxidation is essential to understand the electrical conductivity activation of these kinds of films. This work examines this process induced by cyclic voltammetry in poly(o-toluidine) (POT) films synthesized in H2SO4 solution. In situ electrochemical quartz crystal microbalance (EQCM) and vis-NIR spectroscopy provide singular information complemented with the global response of current. We propose an electrochemical mechanism for the POT electrical conductivity activation by correlation of mass and spectroscopic data. On the one hand, anions are inserted during the formation of conducting polarons (PC), which have a spectral signal at 840 nm. On the other hand, protons are expulsed when the isolated polarons (P*) detected at 420 nm are oxidized.