Spectroscopic Investigation of Iron Salts Doped Polyaniline

摘要

Iron salts have been doped into emeraldine base (EB) successfully using a chemical route. Both FeCl3 and FeSO4 were doped separately into EB in acetonitrile with metal ion and tetramer in the ratio of 4 : 1. The doped samples were characterized by UV-vis absorption, Mossbauer and fourier transform infrared (FTIR) spectroscopy. UV-vis spectra showed a suppression of the characteristic band of EB at 660 nm with an extended absorption towards the infrared regions for both the doped samples. FeSO4 showed electronic absorption behavior similar to the features of acid doped EB. Mossbauer spectroscopy confirmed the presence of single oxidation and high spin states of Fe(III) and Fe(II) in the respective doped polymers. No signature of Fe2+ was observed in the Fe3+ doped EB from the Mossbauer spectrum. FTIR spectroscopy showed a shift towards the lower wave number for the iron salts doped EB as compared to the pristine polymer. An increase in the intensity of the band at 1140 cm(-1) is observed, which corresponds to the electronic like absorption confirming the doping of EB.