Polyaniline (PANi) is unique among conducting polymers because of its reversible electronic properties. Protonation with a strong acid (“doping”) produces the conducting form, whereas deprotonation by a base (“dedoping”) produces the insulating form. It can then be “redoped” with the same or a different acid. The dopant influences properties such as conductivity and solubility, while also determining the morphology of PANi nanomaterials during their synthesis. We have prepared polyaniline nanofibers in 1 M HCl and HClO₄. These have both been dedoped and subsequently redoped with HCl, HClO₄, 10-camphorsulfonic acid (CSA), and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA). Scanning electron microscopy images show that no significant changes in morphology (i.e. fiber diameter) are induced by redoping with either the same acid or a different acid than used when first synthesized. Further, UV-Vis and FTIR spectra indicate that there is no degradation of the molecular structure. Therefore, dopant cycling could be used to modify certain properties independently of the nanoscale morphology pre-determined by the initial dopant.