TIME-RESOLVED INVESTIGATIONS OF THE ANION INTERCALATION IN CONDUCTINGPOLYMERS BY MICROELECTRODES

The reversible redox process of electrochemically formed polyaniline i s accompanied by an intercalation of anions and protons. The rate of i ngress and egress of anions depends on the size of the anions, eg p-to luenesulfonate is much slower than anions like ClO4- or HSO4-. Because of the large current densities (especially during reduction of the fi lm) a separation of these fast anions requires the use of microelectro des. In this work small inorganic anions are compared, the mobility de creases in the sequence Cl- > HSO4- > ClO4- > NO3- > H2PO4- and the eg ress of the latter is 100 times slower than the egress of Cl-. The inf luence of size, electric field, and polarizability is discussed. (C) 1 997 published by Elsevier Science Ltd.