Raman and infrared spectra of polyaniline

The structure of polyaniline has been determined by Raman and infrared spectroscopy. The polyaniline prepared by the chemical or electrochemical oxidation of aniline in acidic media consists of reduced repeat units [−C6H4NHC6H4NH−] and protonated oxidized repeat units [−C6H4NC6H4N+H−]. A− or [−C6H4N+HC6H4N+H−]. 2A−, where A− is a dopant. Alkali treatment dedopes the protonated oxidized repeat units, while electrochemical reduction converts the oxidized repeat units to the reduced repeat units. The highly reduced polyaniline is sensitive to air and the reduced repeat units are changed to the oxidized repeat units [−C6H4NC6H4N−] by exposure to air.