Mobility of alkali cations in polypyrrole-dodecyl sulfate

Due to the immobility of the large dodecyl sulfate anion, the mobile ions in polypyrrole-dodecyl sulfate are small ions from the solution. Virgin PP-dodecyl sulfate does not contain other ionic species, but already the first reduction causes the incorporation of cations into the membrane. Using in situ AC conductimetry on a double-band platinum electrode, we show that the insertion of cations from the solution into the PP membrane proceeds as a non-cunducting zone advancing from the solution interface toward the substrate. The model allows to estimate ion mobilities in the membrane giving 8.6×10−7 cm2s−1V−1 for K+.