The optimum HCl concentration for the in situ polyaniline film formation

The chemical oxidation of aniline with ammonium persulphate (APS) in aqueous hydrochloric acid solutions to form polyaniline (PANI) films has been studied using the quartz crystal microbalance (QCM) technique. The effect of hydrochloric acid concentration on PANI film deposition was studied. The acid has an effect on the yield and the growth rate of the polymer film deposition. The yield has an optimum value when hydrochloric acid equals similar to0.1 M HCl. This was justified by measuring the UV-Vis absorption for the formed films on glass supports immersed into solutions have the same experimental condition like that used in QCM experiments. Degradation for the formed PANI films during the polymerization was observed at high concentrations of HCl. The degradation quantity depends on the concentration of the acid and the temperature of polymerization. (C) 2003 Published by Elsevier B.V.