Control of polyaniline electroactivity by ion size exclusion

By using an electrolytic salt solution of two anionic species differing by their ionic radius or their molecular size, it is possible to accurately co ntrol the concentration of anionic doping agent without modification of the electrolyte conductivity. The conducting polymer film is electrosynthesize d on the electrode in a solution containing small ions. Once de-doped, the film keeps the memory of the size of the doping anion and can be only re-do ped by comparable or smaller anions. After the synthesis, the film is trans ferred to another electrolyte containing heteropolyanions ensuring the cond uctivity and a variable concentration of small ions acting as dopants. Meas urement of the electroactivity of the polyaniline film is made by linear sw eep voltammetry in classical electrochemical conditions. (C) 2000 Elsevier Science S.A. All rights reserved.