Polyaniline nanotubes and their dendrites doped with different naphthalene sulfonic acids

Abstract

Polyaniline (PANI) nanotubes (130–250 nm in average diameter) doped with α-naphthalene sulfonic acid (α-NSA), β-naphthalene sulfonic acid (β-NSA) and 1,5-naphthalene disulfonic acid were synthesized via a self-assembly process. It was found that the formation yield, morphology (hollow or solid), size, crystalline and electrical properties of the nanostructures are affected by the position and number of –SO 3H groups attached to the naphthalene ring of NSA as well as the synthesis conditions. Moreover, these nanotubes aggregate to form a dendritic morphology when the polymerization is performed at a static state. The micelles composed of dopant or dopant/anilinium cations might act in a template-like fashion in forming self-assembled PANI nanotubes, which was further confirmed by X-ray diffraction measurements, while the aggregated morphology of the nanotubes might result from polymer chain interactions including π–π interactions, hydrogen and ionic bonds.