Soluble polyaniline nanofibers prepared via surfactant-free emulsion polymerization

Polyaniline nanofibers were successfully prepared using fumaric acid as the dopant and ammonium peroxydisulfate as the oxidant via surfactant-free emulsion polymerization. The influence of the polymerization parameters such as the oxidant–aniline molar ratio, the oxidant concentration, the molar ratio of fumaric acid and aniline and the fumaric acid concentration on the yield and conductivity of polyaniline was investigated on the basis of the orthogonal experimental method. The morphology, crystallinity, chemical structure and thermal stability of fumaric acid-doped polyaniline prepared under the optimal polymerization condition and the undoped polyaniline were characterized. The results demonstrated that fumaric acid-doped polyaniline has the morphology of nanofibers with a dense array of nodules, an excellent solubility in organic solvents, higher crystallinity, partially doping state and good thermal stability. But the undoped polyaniline formed granular particle agglomerations in a nearly amorphous state upon dedoping.