Grafting aryldiazonium cations to copper: Insights into wettability behavior of a highly hydrophobic coating with enhanced corrosion performance

This paper describes electrografting of various aryldiazonium salts on copper substrate. The wettability of the functionalized surface was measured to choose an aryldiazonium salt with the lowest surface free energy suitable for developing a hydrophobic surface. In this regard, a nickel film with a micro-nano structure was fabricated using an electrodeposition process followed by the modification with 4-dodecylbenzendiazonium salt. The surface morphology of the nickel coating revealed by a scanning elec-tron microscope showed pine cone-like microstructure with nano-cone arrays randomly dispersed on each micro-protrusion. The wettability of the micro-nano nickel film was increased from 7 degrees for as-prepared nickel coating to 140 degrees after modification with 4-dodecylbenzendiazonium salt and it was unchanged by storing 7 days in the air. The corrosion performance of this highly hydrophobic surface was evaluated in 3.5 wt.% NaCl solution using potentiodynamic polarization and electrochemical impe-dance spectroscopy. The results showed a significant decrease in the corrosion current density (icorr), dou-ble layer capacitance (Cdl), and a simultaneous increase of the charge transfer resistance (Rct), indicating an improvement in anti-corrosion performance.(c) 2023 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.