A study of polypyrrole synthesized with oxidative transition metal ions

Polypyrrole powder and films were chemically synthesized by the reaction of AgNO3, FeCl3, Fe(NO3)3, Cu(NO3)2, or Cu(NO3)2‐AlCl3 with pyrrole in an aqueous solution or a water—toluene two‐phase system. Products were characterized by elemental analysis, IR, scanning electron microscopy with energy dispersive x‐ray analysis (SEM with EDAX), and conductivity measurements. The polypyrrole synthesized from pyrrole with FeCl3 had a composition of C4.00H3.05N0.99Cl0.25. The pressed powder had a conductivity of 2.7 × 10−2 S/cm and the film 2.8 S/cm. All the other metal salts produced films that had the same organic backbone, morphology, and conductivity as the polymer synthesized using Fe(III) salts, regardless of the considerable differences in the reduction potentials of the metal ions. The nature of the anions of the transition metal salts had no effect on the reaction. Anions, however, were retained as the counterions of the cationic polypyrrole backbone and could be easily exchanged with other anions.