New insight into the redox behavior of polyaniline

Polyaniline is one the most promising conducting polymers due to its ability to respond to environmental modifications by change in the properties. Here, we report an unprecedented redox behavior of polyaniline. Namely, propagation of reduction in thin highly organized polyaniline films immersed in acid aqueous medium (see Video 1). The films represent a homogeneous interpenetrating network of nano-sized polyaniline fibrils and water molecules. It is found that the presence of highly hydrated anions like HCOO− favors both short- and long-range ordering, as well as the propagation of reduction in the polymer.