Polypyrrole-latex coatings on ito windows electrochemical and spectroelectrochemical studies

Summary form only given. The electrochemical and spectroelectrochernical studies of polypyrrole-latex coatings of 1 or 3 /spl mu/m thickness, on ITO windows in aqueous and organic media indicate a low electrochrornic effect and a strong capacitive effect. The best contrast was close to 0. 15 unit of absorbance and the average capacitance was 7.5 mF.cm/sup -2//spl mu/m/sup -1/. The range of potential to have a stable behaviour was 1 V. The response time was mostly function of the electrolyte conductivity. The RC constant was from 0.23 s for a film of 1 /spl mu/m in acetonitrile 0.25 M LiClO/sub 4/ to 3.1 s in propylene carbonate 0.3 M LiClO/sub 4/. Electrolyte influence was studied by chronocoulometry in water: HiClO/sub 4/, NiClO/sub 4/; H/sub 2/SO/sub 4/, Na/sub 2/SO/sub 4/; H/sub 3/PO/sub 4/; in propylene carbonate and acetonitrile LiClO/sub 4/. The stability of polypyrrole coatings was studied upon repetitive cyclic voltammetry. The best result was obtained in propylene carbonate. Films only lost 2.5% of charge (C) after 7000 cycles. Polypyrrole-latex coatings have no interest for electrochromic devices by itself, but it can be used as a first conducting layer for displays or electroluminescent diodes. Polypyrrole latex is also very interesting for condensers and for high power capacitors.