Electrochemical, morphological, and spectroscopic study of poly(aniline-co-o-bromoaniline) (PA-co-o-BrA) conducting copolymer

A series of moderately conducting and soluble copolymers of poly(aniline-co-o-bromoaniline) (PA-co-o-BrA) having different compositions was obtained by in the situ copolymerization method using different concentrations of monomer units of aniline and o-bromoaniline in the feed. The physio-chemical properties of the copolymers have been studied with sophisticated instrumental techniques. The electrochemical study of the copolymers was conducted by cyclic voltammetry. The band gap of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the copolymers was evaluated by UV-vis spectroscopy. The morphological study was conducted by scanning electron microscopy and transmission electron microscopy at high magnification which shows non-uniform tubular to globular morphology of the copolymers. Surface profiles of the polymers were studied by AFM analyses, and it has confirmed the smooth surface of the copolymers while the homopolymers possesses non-uniform surfaces. The particle size distribution curve indicates that the particle sizes vary in the range of 5 to 9000 nm, and a small fraction of particles possess a size in the range of 5-10 nm.