Two electropolymerization techniques have been used in preliminary research on polypyrrole, such as potential cycling and galvanostatic modes. The cyclic voltammograms and chronopotentiograms can describe the proceeding of the growth of polypyrrole from various aqueous solutions. The cyclic voltammetry of a polypyrrole film in an electrolyte solution can further characterize the polypyrrole films electrochemically. Some evidence has been shown of doping with cations. Polypyrrole differs with respect to the extent of oxidation, doping anions, and also reduction, doping cations. Such properties can be switched dynamically between anion and cation coupling or hopping through electrochemical oxidation and reduction of the polypyrrole backbone.