Mean redox potentials of polyaniline determined by chronocoulometry

Polyaniline film has various domains with different pi -conjugated lengths. Each domain has an individual redox potential (E-i') and the potential is distributed around a mean redox potential (E degrees). The doping levels (Y ) at various oxidation potentials (E) can be expressed theoretically using E(i)degrees, E degrees and E. Four polyaniline films were electrodeposited on a Pt electrode from four acid solutions: sulfuric, hydrochloric, perchlo ric and benzenesulfonic acid. The redox charge at various oxidation potenti als (E) is determined chronocoulometrically, and the charge gives the dopin g level (M. By simulating the obtained Y-E plots with a newly developed the oretical equation, E degrees is determined for the four polyanilines. The l owest E degrees is obtained for the polyaniline film doped by perchlorate i on. This implies that the film has the longest mean pi -conjugated length.