Synthesis and chemical properties of pyrophosphoric acid-doped polyaniline and copolymers of o-phenylenediamine with aniline and 3,4-ethylenedioxythiophene

The homopolymers of aniline (P(ANi)PA) and o-phenylenediamine (P(PDA)PA) along with the copolymers of PDA with aniline (ANi) (P(PDA/ANi)PA) and 3,4-ethylenedioxythiophene (P(PDA/EDOT)PA) were synthesized via a polycondensation reaction that was initiated with ammonium persulfate in the presence of pyrophosphoric acid (PA). Treating the polymers with an alkaline resulted in the generation of the corresponding neutral polymers. The content of the NH2 groups within the polymers, which contained a P(PDA) unit, was determined by analyzing the N-acetylated polymers using H-1 NMR spectroscopy. Elastic gels were obtained by dipping the PA cross-linked polymers into an organic solvent. The UV-Vis spectra for P(ANi)PA and P(PDA/ANi)PA exhibited absorption peaks corresponding to the cation radical (polaron) and dication (bipolaron) bands. The electrical conductivities of P(ANi)PA and P(PDA/ANi)PA were higher than those of the corresponding neutral polymers.