Polyaniline co-doped with dodecyl benzene sulfonic acid and zwitterionic-based ionic liquids prepared by inverse emulsion polymerization

Abstract

Sulfonate zwitterionic ionic liquids with methyl-imidazolium (mim.ZIL) or triphenylphosphonium (PPh3.ZIL) as the cations were mixed with dodecylbenzenesulfonic acid (DBSA) and used as co-doping agent for the synthesis of polyaniline (PANI) by inverted emulsion polymerization approach in toluene medium. The ZIL-DBSA combination resulted in PANI with higher DC conductivity (σDC) values and the better response was obtained with mim.ZIL/DBSA in a molar ratio of 1.0, with σDC corresponding to around 8 S cm−1. The presence of cetyl trimethylammonium bromide (CTAB) during the synthesis caused an additional improvement of the conductivity, reaching values as high as 16.3 and 14.0 for PANI prepared in the presence of mim.ZIL and PPh3.ZIL, respectively. Electromagnetic interference shielding effectiveness (EMI SE) of PANI samples prepared with different conditions was also investigated in the X-band frequency range. An improved EMI SE, with electromagnetic attenuation of -55 dB was observed for PANI sample prepared in the presence of CTAB and mim.ZIL/DBSA in a molar ratio of 1.0.