Protection of copper from corrosion by superhydrophobization of its surface

Copper and its alloys are widely used in industry due to their high electrical conductivity, thermal conductivity, and plasticity. However, in some neutral environments, copper undergoes corrosion, which degrades its functional properties and reduces its service life. Methods of protecting it from corrosion include treatment with inhibitors, but their environmental safety raises concerns. A promising approach is the creation of superhydrophobic (SHP) coatings, which is why we have studied the formation of SHP coatings on copper using alkylmalonic acids (AMAs) as environmentally friendly hydrophobizing agents. The copper surface was preliminarily structured using laser ablation technique to create multimodal roughness, after which it was modified with solutions of AMAs with alkyl chain lengths of C13 and C16. The resulting coatings exhibited superhydrophobic properties with contact angles (Θ_c) comparable to those of coatings based on stearic acid (C17). Additional rinsing in isopropanol with ultrasonic treatment increased Θ_c for AMAs but had no effect on stearic acid (SA). Tests under moisture condensation and in chloride-containing solutions confirmed the high protective efficiency of C16 AMA-based coatings, which was close to that of stearic acid. It was found that increasing the temperature of the hydrophobizing solution to 60°C or adding low concentrations of corrosion inhibitors (e.g., 0.1 mmol/ L 1,2,3-benzotriazole) enhanced the stability of the SHP coatings. The results demonstrate that alkylmalonic acids, especially those with long alkyl chains, can serve as an effective and environmentally friendly alternative to traditional hydrophobizing agents for protecting copper against corrosion.

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