Revisiting the Redox Transitions of Polyaniline. Semiquantitative Interpretation of Electrochemically Induced IR Bands

• Quantification of redox forms polyaniline. Octameric model for PANI transitions. Back to aniline-black structures. The transitions in acidic medium have been monitored by a combination cyclic voltammetry, situ conductance and FTIR spectroscopy. results the semiquantitative analysis strongly suggest that classical tetrameric does not satisfactorily describe actual structures polymer at different states. An octameric is revisited, with inclusion essential resonant structures, provide an appropriate prediction relative IR intensity changes aromatic C stretching (at around 1520 cm −1 ) quinoid 1590 vibrations observed FTIR, which are difficult interpret considering only 4 aniline rings. Particularly, it found emeraldine state better described as resonance hybrid bipolaronic semiquinoid (polaron lattice) while most charge transferred onset second voltammetric peak comes from additional oxidation this hybrid, becomes unstable electrochemical environment producing mineralization CO 2 release soluble quinones.