ELECTROCHEMICAL COPOLYMERIZATION OF ANILINE AND ANILINE-2,5-DISULFONIC ACID

Electrochemical copolymerization of aniline and aniline-2,5-disulfonic acid (ADSA) was carried out in HCl solutions. The presence of ADSA in hibited significantly the growth of polyaniline (PAn), although the vo ltammetry of the copolymer was still similar to that of conventional P An. As the ADSA concentration increased, the deposition rate of the co polymer decreased rapidly and finally no solid film was deposited on t he electrode surface. When the ADSA concentration was lower than simil ar to 5 mM, the depression effect of ADSA on the growth rate of the co polymer is mainly due to its stronger adsorption at the electrode surf ace. For higher ADSA concentrations, the inhibiting effect of ADSA was dominated by its termination effects, which led to more soluble oligo mers and in turn resulted in lower deposition efficiency. Electrolysis of ADSA solution might result in a water-soluble fully sulfonated PAn .