Mobility of alkalications in polypyrrole-dodecyl sulfate

Summary form only given. Polypyrrole doped with dodecyl sulfate is known to be very stable and morphologically smooth material. Due to the large size of the dodecyl sulfate anion, the mobile species in this material are smaller ions. During the first reduction step after electropolymerization the only mobile ions are cations which are inserted into the membrane from the solution. The next oxidation step involves in addition to the expulsion of cations, also insertion of small anions from the solution. Spatial information from these processes can be obtained by using in situ AC conductimetry on a double band platinum electrode onto which polymer has been deposited [1]. It is shown that during the first reduction, a boundary between the conducting and non-conducting zones proceeds from the polymer-solution interface toward the metal-polymer interface. The rate of this process depends on the alkali cation present in solution and mobilities of cations can be calculated from these results. Cyclic voltammograms taken at the same conditions show considerable differences for Li/sup +/, Na/sup +/, K/sup+/, Rb/sup +/ and Cs/sup+/. The size and state of hydration of cations is discussed in the light of the experimental results.