Hexamethylenediamine functionalized glucose as a new and environmentally benign corrosion inhibitor for copper

A bifunctional N-glycoside namely N,N′-Diglycidyl-1,6-hexanediamine (DHA) was synthesized by the facile reaction of 1,6-hexamethylene diamine and glucose and its corrosion inhibition behavior was evaluated on copper in 3.5% NaCl solution for the first time. A detailed electrochemical study using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and scanning electrochemical microscopy (SECM) was carried out to understand the mechanism of corrosion inhibition shown in the present work. The DHA showed a corrosion inhibition efficiency of >95% at a concentration of 0.27 mmol L⁻¹. The adsorption of DHA over copper surface followed the Langmuir isotherm. The surface and the electrochemical reactivity of the inhibitor-modified Cu samples in 3.5% NaCl solution was examined by the SECM technique, demonstrating the formation of a thin inhibitor film with exposure/immersion time in solution containing DHA molecules. The results of surface analysis using scanning electron microscopy (SEM) and ATR-IR spectroscopy supported the adsorption of inhibitor molecules over copper surface. The quantum chemical parameters and molecular electrostatic potential were evaluated using density functional theory, further supported the experimental findings.