Thermal studies on polyindole and polycarbazole

The time and temperature dependences of conductivity of electrochemically prepared polyindole and polycarbazole perchlorates are analysed to understand the aging process and mechanism of conduction. Arrhenius and Mott plots suggest a variable range hopping (VRH) mechanism for polyindole and nearest-neighbour hopping for polycarbazole. The degradation behaviour has been studied by thermogravimetry (TG) and differential thermal analysis (DTA) techniques. The thermal reactions involve loss of dopant, followed by degradation of the polymer backbone. The decomposition temperatures of polyindole and polycarbazole are higher than the values reported in the literature for polyaniline, polypyrrole and polythiophene. The energy of activation for the polymer degradation process has been calculated using three methods and the results are compared.