Chronopotentiometric and open circuit potential analisys of the redox process in poly(3-methylthiophene) (PMT)

Chronopotentiometric measurements for PMT samples show that, for film previously in the reduced state, a maximum in the potentialtime curves was observed. The maximum occurs for times between 1 and 70 ms, the exact value depends on the anodic current density applied. It is followed by a potential minimum between 100 and 1500 μCcm−2 and finally by smooth increase of the potential. For samples lightly oxidized, Q = 6.25 μCcm−2, the maximum potential disappears. In the reduction process, the decrease in the potentials is always linear. The open circuit potential (Eoc) as function of the oxidation charge curves show a strong increase in the Eoc for oxidation charge up to 1000 μCcm−2 followed by a linear increase for higher charges. Otherwise, the reduction process presents only one linear region.