Thermal Properties of Doped Polythiophene

Polythiophene was chemically synthesized, undoped using aqueous ammonia and then re-doped using FeCl(3) and iodine. Doping concentration was changed by changing the duration of doping process. FTIR results indicate the complex formation between polythiophene and each of the dopants. Elemental analysis results for FeCl(3) doped samples show that as the duration increases concentration of Fe(+) ions increases. In case of iodine doped samples atom equivalent of iodine adsorbed per thiophene unit increases with doping duration. TGA analysis shows that FeCl(3) doped samples are thermally stable compared to iodine doped samples. Results of differential thermal analysis indicate that Tg values vary with dopant as well as with dopant concentrations. Reduction in Tg values for all the FeCl(3) doped samples indicate that FeCl(3) acts as plasticizer while increase in Tg values for iodine doped samples indicate anti-plasticizer behaviour of iodine in polythophene.