Ultrasonically Assisted Macrocyclic Ring Compound Coatings for Corrosion Protection of Copper in 3.5% NaCl Solution

Macrocyclic ring compounds are potential corrosion inhibitors due to their high planarity, rigidity, and presence of many heteroatoms such as nitrogen, oxygen, phosphorus, and sulfur. However, their application as corrosion inhibitors has been faced with the challenge of insolubility in most organic and aqueous solvents. To overcome this challenge and to harness the untapped hydrophobic property of these compounds, this research, via ultrasonication method, dispersed a macrocyclic ring compound known as free-based phthalocyanine (Pc) to fabricate a corrosion-resistant coating on the Cu surface. The Cu samples were coated through a 24 h immersion by self-assembly method in different systems of sonicated and nonsonicated solutions of the compound in dimethyl sulfoxide (DMSO). The effect of sonication and immersion duration on the coating morphology, compactness, and consequent corrosion inhibition was analyzed. Electrochemical and surface imaging techniques revealed higher corrosion protection in 3.5% NaCl for the Pc-coated Cu samples after sonication compared to the nonsonicated systems.