Effect of Temperature on the Voltammetric Behavior of Poly‐o‐toluidine

The voltammetric response of poly(o‐toluidine) electrochemically grown films of about 62 nm thick was investigated in the temperature range 218–293 K, using 3.7 M sulfuric acid. The peak current, i_P, corresponding to the first oxidation process decreases with temperature. The peak current depends linearly on the sweep rate at all temperatures. At about 260–270 K, a discontinuity in the i_P vs. T plot is observed. The peak potential for the anodic sweep shifts in the positive direction as the temperature is decreased and the full peak width at half‐maximum, E_W, increases as temperature is decreased. On the other hand, for the cathodic sweep, the peak potential just slightly shifts in the positive direction, and E_W does not change as the temperature is decreased. In strongly acidic solutions, the voltammetric capacity, , is found to be dependent on anion concentration rather than on pH. The temperature dependence of the voltammetric response is explained on the basis that the oxidation process is controlled by ionic movements into the polymer. As the temperature decreases, ionic movements become hindered and a decrease of the polymer voltammetric capacitive current, associated to the redox process, occurs.