Highly ordered mesoporous silica loaded with dodecylamine for smart anticorrosion coatings

The development of nanoscience and technology has devoted significant attention to studies on hollow particles. Among these materials, mesoporous silica nanoparticles have recently attracted attention as potential nanocontainers due to their high stability, biocompatibility, large surface area, controllable pore diameter and easy surface functionalization. Mesoporous silica nanoparticles can uptake, store and release organic or inorganic molecules of various sizes, shapes and functionalities. The aim of this work is to study the use of mesoporous silica with hexagonally ordered (4-14 nm) for active corrosion protection of carbon steel. Mesoporous silica was characterized by X-ray diffraction (XRD), nitrogen adsorption isotherms, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Mesoporous silica structures were loaded with dodecylamine and embedded into an alkyd primer with a weight load ratio of 15 wt.% of mesoporous silica. Kinetics of the release of inhibitor was evaluated by electrochemical impedance measurements in aerated 0.1 mol/L NaCI solution containing 1 wt.% of mesoporous silica at different pH values (2.0, 6.2 and 9.0). The anticorrosive performance of carbon steel coated with alkyd primer loaded with 15 wt.% of mesoporous silica with entrapped dodecylamine was demonstrated by electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). Kinetics of inhibitor releasing curves showed that for pH 2.0 condition the release of inhibitor was faster in comparison to other pH conditions (9.0 and 6.2) showing that this complex porous system provides high loading capacity and efficient inhibitor release in low pH. In addition, due to the release of inhibitor during the corrosion process, well-pronounced active anticorrosion properties and self-healing were provided and confirmed by EIS and SVET measurements. Coated samples were also evaluated in a salt spray chamber and the self-healing effect was also remarkable. (C) 2015 Elsevier B.V. All rights reserved.