Formation mechanism of polyaniline nanotubes by a simplified template-free method

PANI nanotubes with diameters of 100-150 nm with conductivities of single nanotubes as high as 30.6 S . cm(-1) were directly oxidized with APS in the absence of hard templates and acidic dopants. The high conductivity was shown to result from protons produced during the polymerization. The pH decreases with increasing polymerization time, and the morphology changes from hollow spheres to short and long tubes. It is proposed that the micelles formed by the aniline monomer in aqueous solution serve as a soft template for forming hollow spheres at the initial stage. As the polymerization proceeds, these hollow spheres are linearly aggregated and elongated to form short and long tubes.