Optimum reaction conditions for in situ polyaniline films

The deposition of the polyaniline (PANI) films was monitored using the quartz crystal microbalance (QCM) technique. The films were grown from an aqueous dilute hydrochloric acid solution by the chemical oxidation of aniline using ammonium persulphate (APS) as an oxidizing agent. The effect of initial molar ratios of the APS/aniline on the yield and the thickness as well as on the growth rate of the PANI films was studied. The most efficient initial molar ratio of APS/aniline is found to be ∼1.15±0.1. This is in close agreement with the corresponding one obtained during the PANI powder formation in the bulk solution. The higher APS/aniline initial molar ratio results in a degradation of the PANI films.