Silica–polyaniline hybrid materials prepared by inverse emulsion polymerization for epoxy‐based anticorrosive coating

Abstract

ABSTRACTPolyaniline doped with dodecylbenzene sulfonic acid (PAni.DBSA) was prepared by inverse emulsion polymerization of aniline in toluene medium in the presence of silica (SiO2) nanoparticles. The presence of cetyltrimethylammonium bromide (CTAB) during the aniline polymerization results in hybrid material with smaller particle size, as indicated by dynamic light scattering analysis and scanning electron microscopy. Also the electrical conductivity of such hybrid is one order higher, as compared with that prepared without CTAB. Moreover, more ordered PAni chain is obtained as indicated by the red shift of the π–polaron transition band observed by UV–vis spectroscopy and higher crystallinity observed by X‐ray diffraction analysis. Anti‐corrosive properties of carbon steel substrate coated with epoxy resin containing 5 wt % of PAni.DBSA and the corresponding SiO2‐based hybrid materials were evaluated in 3.5% NaCl solution by electrochemical impedance spectroscopy. The coating resistance increases by one order for the epoxy system containing PAni.DBSA/SiO2 hybrid prepared in the presence of CTAB, thus confirming the anticorrosion efficiency of this hybrid. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45505.