Synthesis of sulfonated polyaniline by polymerization of the aniline heterodimer 4-aminodiphenylamine-2-sulfonic acid

The aniline heterodimer 4-aminodiphenylamine-2-sulfonic acid has been polym erized in aqueous ammonium persulfate solution to yield a new form of sulfo nated polyaniline (SPAn). This polymer, obtained as a green powder, is solu ble in aqueous base (violet solution) and polar solvents ( green solution, turning blue on standing). Its FTIR, UV-VIS and EPR spectra are quite simil ar to those of SPAn obtained by direct ring-sulfonation of polyaniline. The room temperature dc conductivity of the polymer is about 1.3 x 10(-5) S/cm , indicative of considerable disorder in the sample. Cyclic voltammetry in 1.0 M HCl shows two redox peaks at E-1/2.1 = 0.50 V and E-1/2.2 = 0.68 V ag ainst Ag/AgCl electrode, characteristic of SPAn. (C) 2001 Elsevier Science B.V. All rights reserved.