Solution characterization of surfactant solubilized polyaniline

Solutions of polyaniline (PANI) doped with camphor sulfonic acid (CSA) in m-cresol are studied with dynamic light scattering. Dynamic light scattering measurements performed on dilute solutions (c ⩽ c∗) show that, while some aggregation is present, PANI-CSA exists as single chains in solution at low concentrations (about 10−4–10−6) in m-cresol. The conformation of the polymer chains was studied as a function of polymer and added salt concentration. We find that the polymers extend as the polymer concentration is lowered and that the increase in the hydrodynamic radius can be expressed by a power law of the electrostatic screening length. This behavior is typical of polyelectrolytes in dilute solution, providing a basis for understanding the conformation changes of this metallic polymer in solution.