Sulphosuccinic acid as a novel dopant for solution processable polyaniline

This work reports on the use of sulphosuccinic acid (SSA), as a new organic dopant for polyaniline (PANI). The SSA doped PANI gives good conductivity and forms dispersions in both polar and non-polar solvents. PANI-SSA can also form aqueous dispersion without the use of any dispersion aids or stabilizers. Doping of PANI is carried out through two techniques, viz. (1) aqueous synthesis of emeraldine base of PANI (PANI-EB) from hydrochloric acid doped PANI (PANI-HCI) salt followed by protonic acid doping (in aqueous solution) with SSA and (2) in situ doping during polymerization of aniline in acid solution of SSA. The conductivity studies revealed that PANI-SSA re-doped from method (1) has a conductivity of 4.2 S/cm, which is four times higher than that of PANI-HCI and one order of magnitude higher than that of PANI-SSA synthesized by in situ method (2). The correlation between conductivity, microstructure evolution and crystallinity for the samples prepared using two different methods is also discussed.