A Novel Polydopamine/ <i>n</i> ‐Octadecanethiol Nanocomposite Coating via Covalent Bonding for Favorable Copper Corrosion Resistance

ABSTRACT To address copper corrosion challenges, we developed a novel composite coating integrating polydopamine (PDA) and n ‐octadecanethiol (ODT) through an effective fabrication strategy. A rapid deposition process (6 min) for PDA was achieved via Ni 2+ ‐catalyzed electrochemical oxidation, followed by in situ ODT grafting through Michael addition reactions. Comprehensive characterization using X‐ray photoelectron spectroscopy and FTIR confirmed covalent bonding between thiol groups of ODT and PDA. The resultant coating demonstrated hydrophobicity (water contact angle: 105°) with good mechanical resilience, maintaining structural integrity after 100 abrasion cycles. Electrochemical analysis in 3.5 wt% NaCl solution revealed enhanced corrosion protection performance: corrosion current density reduced to 0.09 μA cm −2 (1.5 orders of magnitude lower than bare copper), charge transfer resistance elevated to 116.8 kΩ·cm 2 (28‐fold enhancement), and corrosion inhibition efficiency reached 96.7%. This work provides fundamental insights into molecular‐level interactions in composite organic coatings and advances the design principles for next‐generation biomimetic anticorrosion systems.