Molecular assembled self-doped polyaniline copolymer ultra-thin films

A self-assembly technique and copolymerization were used to buildup a self-doped polyaniline (SPANI) ultra-thin film on an indium-tin oxide (ITO) substrate. The monomers used were aniline and its derivative MSAN (m-aminobenzenesulfonic acid). Successful MSAN/AN copolymerization and film formation were simultaneously performed in aqueous solution with the addition of oxidant (APS, ammonium persulfate). The film deposition rate of a high AN/MSAN ratio system is generally higher than that of a low AN/MSAN ratio system. Cyclic voltammetry, UV-vis spectroscopy, and oc-step instruments indicate a systematic dependence of the film thickness of these ultra-thin films on the assembly time and temperatures. The Auger depth profile reveals the elemental distribution in these films and exhibits different deposition rates between AN and NISAN. XPS N-1s, spectra also show the variation of the degree of doping. This SPANI film can be used as an electrochromic electrode in a corresponding device. Carboxyl-terminated-butadiene-acrylonitrile (CTBN) blended with LiClO4 was used as a solid polymer electrolyte. A total solid electrochromic device was assembled as ITO/SPANI/LiClO4-CTBN/PEDOT:PSS/ITO, where PEDOT:SS is poly('3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) as the counter complementary electrode. The device was pale gray at -1.5 V and blue at +1.5 V. (c) 2007 Elsevier Ltd. All rights reserved.