Experimental and theoretical insights to enhanced inhibition of copper corrosion in a typical pickling environment by polyethylene oxide-b-polypropylene oxide copolymer-based hybrid inhibitor

Copper holds significant industrial and commercial significance due to its favourable characteristics finding extensive application in the manufacturing of electronic components, interconnects, wires, pipelines, water supply systems, and heat exchangers. Nevertheless, Cu materials are vulnerable to corrosion, especially in hostile environments containing chloride ions. Although Cu deterioration can be managed through the use of corrosion inhibitors, finding compounds that are non-toxic, available, and effective against copper corrosion is a difficult task which is the reason research on the identification of corrosion inhibitors is still ongoing. In this work, polyethylene oxide-block-polypropylene oxide (PEO-b-PPO) copolymer is explored as an inhibitor for Cu in a 5 wt% HCl solution. Gravimetric and electrochemical techniques in conjunction with surface analysis methods are employed. Computational calculations using the generalized gradient approximation with the Double Numerical Plus Polarization basis set have been performed. The effect of KI addition on the performance of PEO-b-PPO is also investigated. The results disclose that the PEO-b-PPO/KI hybrid is an excellent inhibitor. An inhibition efficiency of 90.84 % is achievable with 15 μM PEO-b-PPO/3 mM KI after 48 h of immersion at 50 °C. The calculated synergism parameter is 2.49 and indicates a strong synergism. The surface analysis results validate the deposition of a densely PEO-b-PPO/ KI protective layer on the Cu surface. The computational calculations reveal that the PEO-b-PPO copolymer interacts strongly with the Cu surface to form a protective layer. The interaction energy for PEO-b-PPO/Cu(111) is −1.12 eV and indicates enabling electronic properties of the polymer for improved interaction with copper atoms.