PH value dependence of the protocalorimetric and optical absorption spectra for polyaniline thin films

Summary form only given. Polyaniline is a very attractive conducting polymer because it exhibits good stability and the redox mechanisms involve the exchange of protons and electrons. Photocarorimetric spec troscopy (PCS) using thermistor is applied to study the heat generation by nonradiative processes in electrodeposited polyaniline films together with the optical absorption. Poly-aniline films were deposited on ITO glasses by constant-potential electrolysis (+0.7V versus Ag/AgCl electrode) in aqueous solution containing 0.5M aniline in 1.0M HCl (1-5 min.). NaOH was added in order to investigate the pH dependence of PCS and optical absorption on polymerization. Although the optical absorption spectra showed several peaks, PCS showed monotonous changes against photon energy. It shows that the increasing of the heat generation by nonradiative processes is different from that of the optical absorption. Also the photon energy dependence of the yield of thermal deactivation is related to the pH values.