Self-assembled necklace-like polyaniline nanochains from elliptical nanoparticles

High quality necklace-like polyaniline nanochains assembled by elliptical nanoparticles have been synthesized in chitosan aqueous solution by a facile dispersion polymerization method. The synthetic procedure is very simple and easy to scale up. The necklace-like nanochains coated by a layer of chitosan are typical doped polyaniline in its emeraldine salt form, which is easy to form stable polyaniline dispersion in water. Open-circuit potential measurements show that the rate of polymerization of aniline has a substantial decrease due to the steric effects of chitosan. The synthetic parameters, such as reaction times, and the concentrations of chitosan, aniline, and dopant acid, have profound influences on the sizes and morphologies of polyaniline nanostructures. A new self-assembly process of elliptical nanoparticles has been proposed for the formation of necklace-like polyaniline nanochains with fluctuant diameters, which is different from that of other one-dimensional polyaniline nanostructures including nanofibers and nanotubes.