Orderly self-assembly of new ionic copolymers for efficiently protecting copper in aggressive sulfuric acid solution

In this study, new ionic polymers (IPs) based on the copolymerization of rigid aromatic phenylmethyl-linked bisimidazole and dibromide derivatives are presented. The prepared IPs display orderly self-assembly in 0.5 mol/L aqueous sulfuric acid solution. Furthermore, the formed IPs aggregates with regular elliptic or circular-like shape exhibit the strong adsorption capability on the studied copper surface in aggressive acid medium, which occurs mainly via the chemical chelation bonding with cuprous ions demonstrated by the FT-IR spectroscopy, Raman spectroscopy together with XPS spectroscopy. In addition, the polarization tests at the different temperatures indicate the physisorption of the IPs aggregates on Cu surface can be presence. The electrochemical measurements show that the formed robust IPs-assemblies layers can protect the studied copper specimens efficiently with the maximal corrosion inhibition efficiency of 97.8% (IP1) and 96.8% (IP2) in aqueous sulfuric acid solution. The results are further understood by the molecular modeling and molecule dynamic simulation, and the electronic density distribution of the surveyed IPs and the optimal equilibrium configurations on Cu slab are revealed and analyzed. The results presented in this study could act as the models for guiding us to develop new organic corrosion inhibitors for metal in aggressive media.