Stable polyaniline dispersions prepared in nonaqueous medium: synthesis and characterization

Peroxodisulfate-induced polymerization of aniline at 10 degreesC in acidic (HCl) nonaqueous medium using dimethyl sulfoxide (DMSO) as the solvent, readily produced polyaniline (PANI) in a stable dispersion form. The stability of the dispersion of PANI in the nonaqueous (DMSO) medium is much enhanced when the same is synthesized in the presence of a support polymer, poly(vinyl alcohol) (PVA) dissolved in the solvent. Results of studies on HCl-doped PANI prepared in DMSO medium by UV-VIS and FTIR spectroscopy support that the doped PANI so obtained is structurally similar to that of doped PANI prepared likewise in acidic aqueous medium. PANI and PANI-PVA composite as prepared in DMSO medium and the relevant isolated dry products were further characterized thermally, employing differential scanning calorimetry (DSC) and thermogravimetry (TG) and morphologically, employing transmission electron microscopy (TEM). HCl-doped PANI prepared separately in DMSO and aqueous media shows electrical conductivity values of 1.07 and 12.0 S cm(-1), respectively, the polymer prepared in nonaqueous medium (DMSO) being measurably poorer in electrical conductivity, (C) 2001 Elsevier Science B.V. All rights reserved.