A kinetic study of in situ polyaniline–gold composite film formation

Chloroaurate acid (HAuCl₄) was used as an oxidant and aniline (ANI) was used as a reducing agent to prepare a polyaniline–gold (PANI-Au) composite film by in situ polymerization. The formation of the composite film was monitored using a quartz crystal microbalance (QCM). The effects of the concentrations of HAuCl₄ and ANI as well as the reaction temperature on the formation of the PANI-Au composite film are discussed. The kinetics of the reaction were investigated by the QCM technique. The results indicate that the kinetics of the reaction are of order 0.5 with respect to HAuCl₄ and 1.5 with respect to aniline. The film growth rate increased with increasing ANI, HAuCl₄ concentration and reaction temperature. The activation energy calculated from the temperature dependence of the growth rate was 40.32 ± 0.15 kJ/mol. In situ UV-visible spectra of the reaction process were obtained and compared to the reaction process using the QCM technique.