Synthesis and NMR characterization of a novel polyaniline derivative - Thecopolymer of 2-methoxyaniline and 3-aminobenzenesulfonic acid

The synthesis and solution-state NMR investigation of the structure of a no vel type of water-soluble polyaniline (PANI) derivative in leucoemeraldine and emeraldine oxidation states is presented. Copolymers of 3-aminobenzenes ulfonic acid and 2-methoxyaniline (PMAOMA) with various monomer molar ratio s were synthesized by chemical polymerization in a hydrochloric acid medium . Due to a large difference in the reactivities of 2-methoxyaniline (OMA) a nd 3-aminobenzenesulfonic acid (MA), the content of OMA in the copolymers w as much higher (over 0.65 of the mole fraction) than in the reaction mixtur e. Structural characterization of the reaction products was performed using one- (H-1, C-13) and two-dimensional (GHSQC and GCOSY) NMR spectroscopy. T he NMR data indicated an almost block structure of OMA sequences of variabl e length separated by shorter sequences of MA units. It was also shown that the incorporation of MA units in the copolymer chains favors the formation of a less oxidized material.