Synthesis and characterization of chlorinated polyaniline

Summary form only given. Chlorinated polyaniline (Cl-PAn) with different Cl content has been synthesized in aqueous HCl/(NH/sub 4/)/sub 2/S/sub 2/O/sub 8/ system. The chlorination degree depends on aqueous HCl concentration in the reaction medium. The optimum condition to prepare Cl-PAn with high solubility and electrical conductivity is 6. 6 N HCl, equivalent monomer and oxidant concentration and at room temperature. This kind of Cl-PAn is 100% soluble in THF both in undoped and doped state, and its electrical conductivity is around 10/sup -4/S/cm. GPC result indicates that it has low number average molecular weight (Mn = 3523) and narrow molecular weight distribution (Mw/Mn = 2.14). Elemental analysis, FTIR, UV-Vis spectra and cyclic voltamograms of Cl-PAn are similar to those of poly (o-chloroanitine), indicating that Cl-PAn has similar structure as poly(o-chloroaniline). GC-MS and FTIR spectra demonstrate that chlorination happens at first on the monomer, then the chlorinated aniline homopolymerizes or copolymerizes with aniline. Once HCl concentration is over 7N, bi- or tri- chlorine substituted aniline can be formed, leading to great decrease in polymer yield and electrical conductivity.