Effect of sulphuric acid on the properties of polyaniline-HCl salt and itsbase

The effect of H2SO4 On polyaniline-HCl salt and its base was studied for di fferent concentrations of the acid (0.1, 1.0, 4.0, 8.0, 13.0 and 18.0 M) fo r a duration of one day and five days. The H2SO4 treated polyaniline sample s were characterised by conductivity and UV-vis, FT-IR and EPR spectroscopi c measurements. Due to the incorporation of H2SO4 in the polymer chain sign ificant effects on polyaniline-HCl salt were observed, while for the polyan iline base doping occurs depending on the concentration of H2SO4 The extent of doping and the incorporation of the sulphate group in the polymer chain are revealed by the spectroscopic and conductivity studies. The conversion of polyaniline base to the salt form is less efficient by H2SO4 doping whe n compared to doping by HCl. (C) 2000 Elsevier Science Ltd. All rights rese rved.