Novel Schiff base derivatives: Enhanced corrosion protection for copper in NaCl solutions – Electrochemical insights and theoretical analysis

Abstract

This study investigates the corrosion inhibition properties of two recently synthesized Schiff bases, namely 4-bromo-2-(((2-((2-hydroxyethyl)amino)ethyl)imino)methyl)phenol (BHA) and phenyl-2-(((2-((2-hydroxyethyl)amino)ethyl)imino)methyl)phenol (PHA), for copper in a 3.5 wt% NaCl solution. The novelty of this work lies in the use of these Schiff bases, which have not been previously studied in this context, thereby providing new insights into their potential as effective copper corrosion inhibitors. The inhibition performance of the Schiff bases was evaluated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The potentiodynamic polarization results demonstrated high corrosion inhibition efficiencies of 85.16 % for PHA and 82.78 % for BHA at a concentration of 1 mM, indicating a mixed-type inhibition process with cathodic predominance. The adsorption of these inhibitors on the copper surface was found to follow the Langmuir adsorption isotherm, and the adsorption constants (K_ads) and Gibbs free energies (ΔG*_ads) were calculated. Quantum chemical calculations, in conjunction with Monte Carlo (MC) and molecular dynamics (MD) simulations, provided further insight into the adsorption mechanisms and supported experimental findings, thus offering a comprehensive understanding of the inhibitors’ efficacy.