Anion exchange nature of emeraldine base (EB) polyaniline (PAn) and a revisit of the EB formula

The anion exchange nature of emeraldine base (EB), which is totally unexpected from the conventional EB formula, is reported here. Based on the ion exchange experiments of this work as well as published ESCA data, EB is suggested to be a mixture of undoped emeraldine with doped emeraldine, in which the counterion is hydroxide ion. This is in contrast to the commonly held concept that identifies EB as undoped emeraldine. Accordingly, a modified EB formula is proposed.