Brazil. Researchers at the Federal University of Rio de Janeiro have prepared hybrid silica-polyaniline materials by reverse emulsion polymerization for epoxy-based anticorrosive coatings.
Polyaniline doped with dodecylbenzenesulfonic acid (PAni.DBSA) was prepared by reverse emulsion polymerization of aniline in toluene medium in the presence of SiO2 nanoparticles.
The presence of cetyltrimethylammonium bromide (CTAB) during aniline polymerization results in hybrid material with a smaller particle size, as indicated by dynamic light scattering analysis and scanning electron microscopy. Also the electrical conductivity of such a hybrid is a higher order, compared to the preparation without CTAB. In addition, a more orderly PAni chain is obtained as indicated by the redshift of the transition band π-polaron observed by UV-vis spectroscopy and greater crystallinity observed by X-ray diffraction analysis.
The anticorrosive properties of the carbon steel substrate coated with epoxy resin containing 5% by weight of PAni.DBSA and the corresponding SiO2-based hybrid materials were evaluated in 3.5% NaCl solution by electrochemical impedance spectroscopy. The resistance of the coating increases in an order for the epoxy system containing hybrid PAni.DBSA / SiO2 prepared in the presence of CTAB, thus confirming the anticorrosive efficacy of this hybrid.
Source: http://onlinelibrary.wiley.com/doi/10.1002/app.45505/abstract?campaign=woletoc
