Highly crystalline and thin polyaniline nanofibers oxidized by ferric chloride

Highly crystalline polyaniline (PANI) nanofibers with 16–23 nm in diameter were successfully prepared by using FeCl3·6H2O as the oxidant in the presence of inorganic acids (e.g. HCl, H2SO4, H3PO4 and HF) without any external template. It is found that the effects of the dopant structure and the molar ratio of FeCl3 to aniline on the morphology and diameter of the resulting PANI nanofibers are weak when FeCl3·6H2O was used as the oxidant. It is proposed that low redox potential of FeCl3 results in thin nanofibers with ∼20 nm in average diameter, indicating that FeCl3 is an excellent oxidant to prepare really nano-scaled fibers or tubes of PANI or its derivatives via a self-assembly process.