Synthesis and characterization of polypyrrole nanofibers

Abstract

Compared to other conducting polymers in their bulk form, polypyrrole nanofibers have shown higher sensitivities and faster responses as gaseous chemical sensors. However, the lack of a consistent and simple method to mass produce these nanofibers has prevented their incorporation into commercial devices. This project has produced polypyrrole nanofibers using a novel chemical oxidative polymerization method. Important parameters of the synthesis process are: (1) supersaturated melt of iron (III) chloride hexahydrate as an oxidant, (2) temperature of 50°C, (3) high oxidant to monomer ratio, (4) methanol as a solvent for pyrrole monomers and (5) the use of a stirring bar at 700rpm. The main mechanism for the formation of nanofibers is believed to be based on the rapid formation of bipyrrole and the pyrrole oligomers, which subsequently homogeneously nucleate and serve as growth centers.