Organic-inorganic hybrid coatings modified with cerium ions will be prepared by the sol-gel process in order to perform a structural and electrochemical investigation. The effect of different concentrations of Ce(III) and Ce(IV) ions in the inorganic phase will be studied focusing on the following aspects: formation and structure of the hybrid network, anti-corrosion properties and the "self-healing" effect. The organic-inorganic hybrid coatings, based on methyl polymethacrylate (PMMA) covalently bonded with the inorganic silica phase, containing different concentrations of cerium, will be deposited on carbon steel and aluminum alloy substrates by dip coating. The structural characterization will be carried out by nuclear magnetic resonance spectroscopy (NMR) 29Si and 13C, X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS), small angle X-ray scattering (SAXS), combined with morphological analysis by atomic force microscopy (AFM), scanning electron microscopy (FEG-SEM) and optical microscopy. For analysis of thermal properties thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) will be used. The corrosion protection efficiency of the coatings and the "self-healing" effect of artificially damaged samples will be investigated before and after immersion in saline and saline/acid medium by electrochemical impedance spectroscopy (EIS), polarization curves and the scanning vibrating electrode technique (SVET), the latter performed during the internship abroad.
News published in Agência FAPESP Newsletter about the scholarship: