Polyaniline was dissolved mechanically into NMP solvent. Polyaniline molecular chains aggregate with the help of NMP, and show compact coil conformation giving rise to a low viscosity. The polyaniline solution added with LiCl gives higher viscosities than that without LiCl due to the strong interaction such as hydrogen bonding between polyaniline and NMP. The addition of LiCl destroys or eliminates the aggregation and polyaniline chain has expanded coil conformation exhibiting higher viscosity. Polyaniline solution was extruded and wet pun into chilled water. various fibers were obtained by changing draw ratios and dried in a vacuum oven in a certain time interval. After drying, the fibers were thermally extended at 210℃ and investigated by using WAXD. The fibers spun with high draw ratios do not exhibit a higher crystallinity or orientation compared with the as-spun fiber. But fibers extended at 210℃ exhibit a higher crystallinity and orientation with increasing extension ratio due to the formation of microcrystallite resulted from the physical crosslinking of polyaniline chains. The polyaniline solution showed the phase change with time. As the time went on until the gelation point, the polyaniline film casted had larger pores by the aggregation of molecules but smaller voids formed by dipping the film into the anti-solvent. the fiber spun just before the gelation point showed the high modulus and tensile strength.Consequently, it was found that the fiber cross-section morphology and the mechanical properties were strongly dependent on the wet-spinning conditions.
