Amic acid doping of polyaniline: Characterization and resulting blends

Amic acids are found to be dopants for polyaniline (Pani). In particular, polyamic acids, the precursors to polyimides, react with Pani to form an all-polymer conducting matrix composed of protonated Pani and the polyamate counteranion. The acid/base interaction provides the driving force for molecular miscibility. The doping reaction is probed further by using a model system based on a monomeric diamic acid. It is found that the conductivity in the all-polymer matrix is limited by geometric constraints between the two polymers. Upon imidization of the Pani/polyamic acid blend, the doping reaction is reversed resulting in a non-conducting Pani/polyimide blend. However, the miscibility between the two polymers is still retained forming a "frustrated" blend in which the two polymers are frozen into a homogeneous, non-equilibrium state unable to phase separate as a result of physical restrictions.