Novel conducting polymer poly [bis(phenylamino)disulfide]: Synthesis, characterization, and properties

A bis(phenylamino)disulfide was prepared through the reaction of S,Cl, with aniline, and its configuration was confirmed with elemental analysis, Fourier transform infrared (FTIR), Fourier transform Raman (FT-Raman), and H-1 NMR spectroscopy. A novel conducting polymer, poly [bis(phenylamino)disulfide] (PPAD), was synthesized from bis(phenylamino)disulfide by both chemical and electrochemical polymerization. The structure of this polymer, in which the side-chain disulfide bonds were linked to the nitrogen atoms of the main-chain polyaniline, was characterized with FTIR, FT-Raman, gel permeation chromatography, electron spectroscopy, and X-ray photoelectron spectroscopy. A four-probe measurement revealed that the electrical conductivity of PPAD was 1.8 x 10(-2) to 2.1 x 10(-3) S cm(-1), depending on the doping agents and the pH of the medium for either chemical synthesis or electrochemical synthesis. The conductivity, molecular weight, and spectroscopic properties of the polymer, in comparison with those of polyaniline, showed decreases in the polaron delocalization, structural order, and doping level of the main chain because of the steric hindrance of side-chain S-S bonds. The cyclic voltammograms of the polymer and the monomer showed that the redox reactions (doping/undoping processes) of the main chain (pi-conjugated system) occurred in almost the same potential range of -0.3 to 0.3 V versus an Ag/AgCl (saturated KCI) electrode as that of thiol (thiolate anion)/ disulfide of the side chain in PPAD: the bond cleavage (reduction) and formation (oxidation) reactions of the disulfide bond in the polymer became easier and more reversible than those of the monomer. These results suggested that this conducting organodisulfide polymer might be a candidate material for energy-storage devices such as lithium secondary batteries, proton-exchange batteries, and electrochemical capacitors. (C) 2004 Wiley Periodicals, Inc.