Studies on chemical oxidative copolymerization of aniline and o-alkoxysulfonated anilines:: I. Synthesis and characterization of novel self-doped polyanilines

The chemical oxidative copolymerization of aniline (An) with o-alkoxysulfonated anilines, i.e., 1-(o-amino)-propane-3-sulfonic acid (APPrS) and 1-(o-amino)-butane-3-sulfonic acid (APBuS), was a new way to produce water-soluble and self-doped polyaniline derivatives. Poly(An-co-APPrS) and poly(An-co-APBuS) were obtained in H2SO4 acidic medium by chemical oxidation, using ammonium persulfate, of a comonomer mixture containing An and APPrS, or APBuS, in various initial ratios. The copolymers thus obtained with high or low yields, were characterized by elemental microanalysis, FTIR spectroscopy, size exclusion chromatography and conductivity measurements. Due to the electron-donating effects of the alkoxysulfonated groups, the two aniline-derivatives were easily incorporated in the macromolecular chains and strongly enhanced water-solubility of the products. The electrical conductivities of these copolymers, which depend on both self- and external-dopings, were reduced by the incorporation of alkoxysulfonated substituents compared with the one of parent polyaniline.