Wet spinning of pre-doped polyaniline into an aqueous solution of a polyelectrolyte

We report the preparation of highly conductive polyaniline (PANi) fibers produced via a wet-spinning process into different coagulation solvents or solutions. To the best of our knowledge, this paper shows the first successful spinning of PANi fibers into an aqueous environment where no post-doping of the fiber is needed. Aqueous solutions of different salts, small anionic molecules, small cationic molecules, polycations, and polyanions are studied. Best results are obtained using an aqueous solution of a polyanion as a coagulation bath. The resulting fibers exhibit good length, stability, and morphology. An in depth study of the relationship between the fiber properties and the concentration of a polyanion in the aqueous bath (poly(sodium 4-styrenesulfonate), PSS) is performed. It is shown that PSS solutions stabilize the PANi fibers without dramatically changing the conductivity of the fibers. It is believed that this stabilization is a result of numerous ionic interactions between cationic centers on the PANi and anionic groups on the polyanion. This new preparation method should be industrially viable.