Integrated Dual-Functional ORMOSIL Coatings with AgNPs@rGO Nanocomposite for Corrosion Resistance and Antifouling Applications

The reduced graphene oxide/silver nanoparticle (AgNPs@rGO) nanocomposite was prepared via a simple, straightforward, and environmentally benign thermal reduction method. Dual-functional ORMOSIL (organically modified silicate) coatings with AgNPs@rGO nanocomposite were developed for corrosion and fouling inhibition of copper metals. Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible–near-infrared absorption spectrum (UV–vis–NIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) spectra indicated that the metallic silver nanoparticles (AgNPs) were successfully formed. Scanning electron microscopy (SEM), scanning probe microscopy (SPM), and transmission electron microscopy (TEM) demonstrated that the spherical AgNPs were uniformly distributed across the GO sheets with an average size of 14.9 ± 6.9 nm. Density functional theory (DFT) was used to explore the corresponding adsorption mechanism. The AgNPs@rGO nanocomposite could be well-dispersed into the ORMOSIL sols because of the strong binding strength between the AgNPs and thiol functionality of the sol precursor. Results from electrochemical tests indicated that the introduction of AgNPs@rGO nanocomposite would effectively improve the corrosion resistance of ORMOSIL coatings in a simulated marine environment. The well-dispersed performance of AgNPs@rGO nanocomposite in the coating was favorable to filling the original defect and enhancing the complication of penetration path. Combining the merits of flexible PDMS and AgNPs@rGO nanocomposite into the sol–gel coating greatly improved the corrosion resistance of the hybrid coating. The antifouling test indicated that the ORMOSIL coating with AgNPs@rGO nanocomposite showed excellent antibacterial and antialgae properties. The ORMOSIL coatings filled with AgNPs@rGO nanocomposite have promising applications in the protection of copper metal from corrosion.