(722ax) Synthesis and Reversible Wettability of Conducting Polyaniline Films Consisting of Helical Microfibers

Conducting polyaniline (PAni) films consisting of helical microfibers were electrochemically deposited in acetonitrile-water electrolyte containing aniline monomer and perfluorooctanesulfonic (PFOS) acid. The films have extended network structure composed of interconnected helical PAni fibers. Typical length of the fibers is about 10-20 microns and the diameter ranges from 200-800 nm but most around 400 nm. The helical fibrous structure is supposed to form through a supermolecular templating process. The surface of the PFOS-doped PAni films exhibited superhydrophobicity with a water contact angle of 153º. Reducing the PFOS-doped PAni films in tetraethylammonium perfluorooctanesulfonate (TEAPFOS) solution by negative potential led to dedoped PAni (in leucoemeraldine base form) films, which were superhydrophilic (water contact angle close to 0º). When oxidizing the superhydrophilic dedoped PAni film by positive potential, the superhydrophobic PAni (in PFOS-doped emeraldine salt form) surface was regenerated. By controlling the electrical potential, PAni films were changed between doped state and dedoped state, resulting in reversibly switchable superhydrophobic and superhydrophilic surfaces. Details on the preparation and characterization of the conducting PAni films are presented including scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), UV-Vis spectroscopy, cyclic voltammetry (CV), contact angle, and conductivity measurements.