Experimental and theoretical study of hierarchical NiCo-TiO2 nanocomposite superhydrophobic surface for improving corrosion resistance

Abstract

The superhydrophobicity of surfaces is a critical characteristic to prevent the corrosion problem, as a significant challenge under corrosive environments. In the present study, the nickel-cobalt (NC) alloy micro-nano hierarchical structure, along with the insertion of TiO2 nanoparticles (NCT) prepared by the economical and facile electrodeposition and myristic acid (MA) fatty acid physically adsorbed on the surface of NCT to reduce surface energy. The stability improvement of the prepared micro-nano scale composite due to the presence of TiO2 nanoparticles preserves the superhydrophobic feature created by the hierarchical structure and the fatty acid placed on the surface. The surface morphology and roughness, and the crystal structure of electrochemical deposited films were investigated using FE-SEM, AFM and XRD techniques, respectively. Also, mechanical and chemical stability, wetting behavior, and anti-corrosion properties were evaluated. The contact angle of 153° for the optimized Christmas tree-like nanocomposite (MA/NCT-2) implies the superhydrophobic property of the prepared coating. The excellent stability of MA/NCT-2 under corrosive different conditions, along with its supreme corrosion resistance confirm the potential of MA/NCT-2 for corrosion protection. Moreover, molecular dynamic (MD) simulations were performed in this first trial to determine wettability, intrinsic propagation mechanism, and structural evolution of water nanodroplets on copper (Cu) substrate and various coatings. The pristine substrate and NCT coating electrodeposited on the surface of Cu (NCT@Cu) were used to model the composite surfaces coated with MA. The last part concerned the study of the contact of this protective material with those surfaces and its possible improved performance as a superhydrophobic coating.