Solution-cast polypyrrole film: the electrical and thermal properties

Polypyrrole (PPy) solution has been prepared by dissolving PPy powder in m-cresol after doping with sodium dodecylbenzenesulfonate, and free-standing film of PPy has been cast from the solution. The PPy prepared in this way has very shiny smooth surfaces and contains approximately 13% of the solvent. The activation energy of electrical conduction was found to be 0.14 eV. It has been concluded that the solvent, i.e. m-cresol, plays an important role in electrical conduction as well as the enhancement of electrical conductivity during annealing at around 120 °C. The decrease in electrical conductivity as the PPy film is heated above 140 °C is due to the loss of solvent.