Chemical synthesis of coral-like nanowires and nanowire networks of conducting polypyrrole

Coral-like nanowires and nanowire networks of conducting polypyrrole (PPy) were synthesized by chemical oxidation polymerization of pyrrole (Py) monomers in a dodecyl-benzene sulfonic acid (DBSA) aqueous solution with FeCl3 as oxidant and poly(vinyl-alcohol) (PVA) as additive. The morphology of PPy was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the morphology of the as-prepared PPy was significantly affected by the concentration of DBSA and pyrrole monomer as well as by the addition of poly (vinyl-alcohol). Coral-like nanowires were produced in a dilute solution with 0.07 M DBSA and 0.07 M pyrrole. But when the concentration of DBSA and pyrrole is higher than 0.1 M, only granular PPy was obtained. Interestingly, coral-like nanowire network morphology was formed with PVA as an additive in the solution. The results indicate that PPy nanowires could be obtained at slow reaction and aggregation rate in the dilute solution or with adding PVA. The conductivity of the compressed pellets of the PPy powder with coral-like nanowire network morphology was 43.18 S/cm, which is much higher than that of the PPy with granular morphology. Elemental analysis, FTIR and X-ray diffraction (XRD) characterized the structure of the resulting PPy. (C) 2003 Elsevier B.V. All rights reserved.