Effect of Mortar-Pestle Grinding on Conductivity of Ferric Chloride Doped Polypyrrole

With four-probe technique, we investigated the effects of the mortar-pestle grinding on the conductivity of ferric chloride doped conducting polymer polypyrrole, which had been synthesized by in situ polymerizing the monomer pyrrole in aqueous solutions in the presence of the oxidant iron (III) chloride. As the mortar-pestle grinding duration increased from 0 to 4 hours, the conductivity of the synthesized polypyrrole was found to decrease from about 100 to 10 S/m. In the meantime, the sizes of the grinded polymeric particles were found to decrease from 40.6 to 3.36 m as the grinding duration increased from 0 to 4 hours. Our results demonstrated that the grinding shortened conjugation lengths of the polymeric chains should be responsible for the decrease in the conductivity of the polymer.