Polyaniline: Pernigranile, an isolable intermediate in teh conventional chemical synthesis of emeraldine

The conventional chemical oxidative polymerization of aniline to polyaniline in the emeraldine oxidation state using acidic ammonium peroxydisulfate (aniline: peroxydisulfate ≈ 4:1; aq. 1. ON HCl; ≈0 °C) was found to proceed via the intermediacy of the fully oxidized pernigraniline oxidation state (readily isolable as the base form). The intermediacy of the pernigraniline oxidation state was first detected by using a novel potential profiling technique in which the oxidation potential of the system was continuously monitored as a function of polymerization time.