With four-probe and laser light scattering techniques, we have studied the dependencies of the conductivity and the particle sizes of p-toluene sulfonic acid doped polypyrrole on the mechanical grinding time. As the chemically synthesized polypyrrole was mechanically grounded in a mortar from 0 to 8 hours, its conductivity decreased from 607 to 10 S/m while and its particle size decreased from 27 to 4 m. If the mechanical grinding continued, the conductivity of the polymer was found to be up to 1680 S/m. Our results have demonstrated that mechanical grinding is an effective method to control the conductivity of the p-toluene sulfonic acid doped polypyrrole.
