Copolymers of aniline with anthranilic acid and two esters, ethyl and methyl anthranilate, were prepared through chemical synthesis using a variety of acids as the dopant. All polymers and copolymers were characterized by UV-Vis, Fourier transform infrared (FTIR) and Raman spectroscopies, as well as scanning electron microscopy. The data support the formation of variable amounts of phenazine-like structures due to ortho-coupling polymerization that competes with the para-coupling mode for the construction of the polymer backbone. The electrical conductivity and the solubility in a diversity of solvents were determined and correlated with the spectral data. The copolymers of aniline with anthranilic esters are more soluble than the corresponding polyanilines. In addition, the conductivity of the copolymer with methyl anthranilate doped with trifluoroacetic acid is of the same order of magnitude as that observed for the regular polyanilines. Overall, higher conductivities were obtained for all polymers and copolymers doped with hydrochloric acid and trifluoroacetic acid.
anthranilic esters; polyaniline; copolymerization; conducting polymers; Raman spectroscopy
