The spectral and morphological studies of the conductive polyaniline thin film derivatives by the in situ copolymerization

Abstract

Thin film of copolymers of poly(aniline-co-2-iodoaniline) are obtained by in situ copolymerization of aniline and 2-iodoaniline as the startup monomers by chemical oxidation upon varying the molar feed to ratio of monomers to procure the different compositions. In the UV–Vis study the characteristic bands at 281 nm, 315 nm for copolymer and homopolymer, are observed, respectively, which are mainly due to π–π* (pi to pi) transition. The blue shift in the band indicates that there is a decrease in the extent of conjugation system along the copolymer. The properties of copolymer could be modified by varying the monomer ratio in copolymerization reactions. The 1H NMR studies reveal the actual structural details of these polymers.TEM images of polyaniline and copolymer films at high magnification show a flat- shaped tubular morphology. Surface profile of the polymers has been studied by AFM which suggest that copolymer has smooth surface while homopolymer having non-uniform surface. The particle size varies in the range of 5–10,000 nm for polyaniline while in case of copolymer it lies in a narrow range of 100–150.