Spectroscopic and Electrical Studies of Ferrous Sulphate Doped Polyaniline

Abstract

Polyaniline (PANI) has been synthesized by chemical oxidative polymerization technique with potassium dichromate oxidant in aqueous hydrochloric acid medium. After polymerization, the polymer so prepared is doped with ferrous sulphate, a transition metal salt, with tetrahydrofuran and water as solvents. The undoped/doped samples were characterized by various techniques such as UV-visible spectroscopy, FTIR spectroscopy, X-ray diffraction and dc conductivity measurements. UV-visible absorption studies revealed the presence of cation/polaron transitions and the presence of direct optical transitions. FTIR studies provide information regarding structural changes in the backbone of PANI with doping concentration. X-ray diffraction patterns of powdered polymer composites showed amorphous nature as mostly conducting polymers exhibit. The dc conductivity of PANI-ferrous sulphate composites were measured by two probe method in pellet form at room temperature (300 K) and found to increase with temperature showing the semiconductor behavior of synthesized polymer composites