The ion exchange behavior of polypyrrole (PPy) doped with a variety of dopants (A), namely chloride, nitrate, para-toluene sulfonate (pTS(-)), and dodecyl sulfonate (DS-), was investigated by means of cyclic voltammetry (CV) in NaCl, NapTS, and AlCl3 aqueous solutions. The results show that PPy/pTS and PPy/DS films had the best anion and cation exchange ability, respectively. However, the ion exchange ability evaluated by CV charge cannot describe the exact amount of exchanged ions. For that reason, a new ion exchange experiment was designed to evaluate the amount of ions removed from NaCl aqueous solution to AlCl3 or NapTS aqueous solution. In addition, the ion exchange ratio is defined as the ratio of the charge associated with ion ejection to the synthesis charge, and can be conveniently converted to operating exchange capability (OEC). The ion exchange ratio and OEC can be used to characterize and evaluate the ion exchange ability of PPy/A films in different conditions. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 2307-2314, 2009