SYNTHESIS OF ELECTRICAL CONDUCTIVE POLYPYRROLE FILMS BY INTERPHASE OXIDATIVE POLYMERIZATION - EFFECTS OF POLYMERIZATION TEMPERATURE AND OXIDIZING-AGENTS

Polypyrrole (PPy) films were synthesized by interphase polymerization reactions between aqueous solutions of oxidizer and organic solutions of pyrrole monomer. It was found that the conductivity and morphology of PPy films strongly depend on the diffusivity of pyrrole monomer into aqueous phase. It seems that polymerization should be carried out at lower temperatures in order to obtain homogeneous PPy films with high electrical conductivities. When PPy films were prepared with iron(III) chloride as an oxidant and toluene as an organic solvent, the conductivity increased from 2.7 to 9.7 S cm-1 and film thickness decreased largely by changing reaction temperature from 10 to -5-degrees-C. The conductivity of PPy films was also dependent on the nature of oxidizing agent. The conductivities of PPy films obtained with iron compounds as oxidizing agents decreased in the order; perchlorate, chloride > nitrate > sulfate. The result may be attributed to the difference in extent of doping by counter anions. The maximum conductivity of PPy film prepared with iron(III) perchlorate was 32.6 S cm-1.