Synthesis and characterization of poly (2,2’ bithiophene) via chemical oxidative polymerization

Abstract

Synthesis of poly (2,2’ bithiophene) was carried out by chemical oxidative polymerization. Ferric chloride hexahydrate was used as oxidant. The resulting polybithiophene (PBT) powder was of reddish brown colour. It possesses different structures and properties, depending on the specific reaction conditions. The FeCl3/bithiophene system was examined with respect to the critical reaction parameters which include reactant stoichiometry, temperature, time and reaction medium. The PBT nanostructures were systematically characterized by IR and UV-Vis spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). PBT nanowires were obtained by dissolving bithiophene monomer in 1 mL of acetone and polymerized at FeCl3/bithiophene molar ratio of 30:1 for 30 sec. SEM revealed that the PBT nanowire synthesized at 50 °C, exhibited better morphology and yield than those prepared at temperatures of 40 °C and 60 °C. The polymer was observed to undergo degradation reactions involving two steps, viz. loss of dopant followed by degradation of polymer backbone. PBT has thermal stability of up to 200 °C which offer potential usage for low temperature applications.