Chemical synthesis of highly electrically conductive polypyrrole

Polypyrrole has been preparede by chemical polymerization in FeCl3 solution with various solvents. Using methanol as a solvent, along with suitable polymerization conditions, the polypyrrole obtained shows an electrical conductivity as high as 190 S/cm. It is found that the oxidation potential of the solution strongly affects the polymerization process and conductivity. The optimum value of oxidation potential (versus SCE) to produce a highly conductive polypyrrole is approximately 500 mV. When the oxidation potential of FeCl3 in methanol solution is controlled by adding FeCl2 before the reaction, the conductivity of the polypyrrole can be increased up to 220 S/cm, comparable to values obtained by electrochemical polymerization.