Inter- and intra-molecular synergism in designing MgO-MCC composite-based coating: An efficient inhibitor for excellent anticorrosion performance

Abstract

Polymer-based corrosion inhibitors are characterized by high efficiency, low cost, and eco-friendliness; however, their underlying mechanisms and modes of action remain poorly understood, presenting a significant challenge in optimizing their performance and effectiveness in practical applications. In this study, we successfully synthesized and thoroughly characterized a novel nanocomposite, combining magnesium oxide (MgO) nanoparticles with microcrystalline cellulose (MCC), and assessed its potential as a corrosion inhibitor for XC18 steel in an HCl 1.0 mol/L environment. The anticorrosive performance of the MgO-MCC composite for XC18 steel under harsh acidic conditions were investigated via electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and surface characterization with a scanning electron microscope (SEM). Morphological analysis suggested the formation of a protective barrier with a fiber-like architecture on the XC18 surface that hindered corrosion. The electrochemical results revealed an increased inhibition performance of MgO-MCC with increasing concentrations reaching a higher efficiency of 87% at 700 ppm. Also, EIS results displayed maximum corrosion resistance achievement in the presence of MgO-MCC-based material (about 147.50 Ω cm2) along with mixed protection mechanism. Advanced theoretical calculations based on density functional theory (DFT) and first-principles density-functional tight-binding (DFTB) were performed to understand the MgO-MCC behavior at metal interface as well as to explore the inter- and intra- molecular interactions involved in the hybrid material formation, complementing the experimental findings. The interfacial mechanism and structure engineering of MgO-MCC composite for functionalizing the surface of metal alloy were also investigated and discussed. MgO-MCC benefits from essential inter and intra-molecular interactions, leading to a robust adsorption layer. The parallel adsorption configuration and mutual interaction establish a stable hierarchical self-assembly structure and stabilize the Fe―O bonds, thus improving the chemical and physical bonding with XC18 steel surface. The results suggest that the synergistic combination of MgO nanoparticles and polar-rich MCC is a valuable approach for designing novel hybrid materials.