| Abstract: | Polyaniline, synthesized by using potassium dichromate as the oxidant, was doped with iodine in order to increase its electrical conductivity. The iodine-doped polyanilines attained a conductivity of 1.83 × 10?3 S/cm, which was about eight orders of magnitude greater than that of intrinsic polyaniline. The iodine-doped polyanilines did not absorb moisture readily when compared to the protonic-acid-doped polyanilines. Fourier transform infrared (FTIR) and x-ray photoelectron spectroscopy (XPS) results indicated that iodine-doping reactions occurred at the N-atoms in the quinoid structural units of the polyaniline molecular chains and consequently formed the charge transfer complexes. The iodine in the iodine-doped polyanilines existed mainly in the forms of I and I anions. As the doping level increased, the relative content of I anions increased. Thermogravimetric analysis (TGA) results showed that there was about 6 wt % of iodine strongly bonded to the polyanilines since they would not evolve even at the structural decomposition temperatures of the polymer backbones. Wide-angle x-ray diffraction spectroscopy (WAXD) results revealed that the intrinsic polyaniline was an amorphous polymer but the regularity of polyaniline chains increased after iodine-doping. The iodine-doped polyanilines also showed a decrease in thermal stability. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1993–2001, 1997 |
