Hammer, Peter [UNESP]Dos Santos, F. C. [UNESP]Cerrutti, B. M. [UNESP]Pulcinelli, Sandra Helena [UNESP]Santilli, Celso Valentim [UNESP]2014-05-272014-05-272013-04-01Progress in Organic Coatings, v. 76, n. 4, p. 601-608, 2013.0300-9440http://hdl.handle.net/11449/74940Siloxane-polymethyl methacrylate hybrid films containing functionalized multiwall carbon nanotubes (CNTs) were deposited by dip-coating on carbon steel substrates from a sol prepared by radical polymerization of methyl methacrylate and 3-methacryloxy propyl-trimethoxysilane, followed by hydrolytic co-polycondensation of tetraethoxysilane. The correlation between the structural properties and corrosion protection efficiency was studied as a function of the molar ratio of nanotubes carbon to silicon, varied in the range between 0.1% and 5%. 29Si nuclear magnetic resonance and thermogravimetric measurements have shown that hybrids containing carbon nanotubes have a similar degree of polycondensation and thermal stability as the undoped matrix and exhibit and excellent adhesion to the substrate. Microscopy and X-ray photoelectron spectroscopy results revealed a very good dispersion of carbon nanotubes in the hybrid matrix and the presence of carboxylic groups allowing covalent bonding with the end-siloxane nodes. Potentiodynamic polarization curves and electrochemical impedance spectroscopy results demonstrate that CNTs containing coatings maintain the excellent corrosion protection efficiency of the hybrids, showing even a superior performance in acidic solution. The nanocomposite structure acts as efficient corrosion barrier, increasing the total impedance by 4 orders of magnitude and reducing the current densities by more than 3 orders of magnitude, compared to the bare steel electrode. © 2013 Elsevier B.V. All rights reserved.601-608engCarbon nanotubesCorrosion protectionElectrochemical propertiesHybrid coatingsPhotoelectron spectroscopySol-gel processAcidic solutionsBare steelCarbon steel substratesCarboxylic groupCorrosion barriersCovalent bondingDip coatingFunctionalizedHybrid coatingHybrid filmHybrid matrixMolar ratioNano-composite structureOrders of magnitudePolymerization of methyl methacrylatePotentiodynamic polarization curvesProtection efficiencySimilar degreeThermogravimetric measurementCarbon steelCoatingsCorrosion resistanceElectrochemical impedance spectroscopyEstersPhotoelectronsPolycondensationPolymethyl methacrylatesSolsSubstratesX ray photoelectron spectroscopyArtigo10.1016/j.porgcoat.2012.11.015WOS:000316425000012Acesso restrito2-s2.0-848741063176466841023506131997120258528696755842986818708650000-0002-3823-00500000-0002-8356-8093