One-Pot but Two-Step Vapor-Based Amine- and Fluorine-Bearing Dual-Layer Coating for Improving Anticorrosion and Biocompatibility of Magnesium Alloy

Hydrophobic coating is of great interest to enhance the corrosion resistance of magnesium alloy implants, which always suffer from rapid corrosion that leads to the failing application under physiological conditions. Plasma-polymerized fluorocarbon (C-F) coating has been widely studied as a substrate protection layer; however, the precise control of the deposition rate of C-F coating with fluorinated alkanes has been a challenge. In this study, a thin, uniform, pinhole-free, polymerlike, and hydrophobic C-F coating was successfully prepared using acetylene (C2H2) as a cross-linking agent, which endows the coating with tunable properties of deposition rate by incorporation of unsaturated bonds. Electrochemical corrosion and in vitro immersion test demonstrated that the C-F coating significantly slows down the corrosion rate of MgZnMn in phosphate-buffered saline solution at 37 degrees C. Furthermore, an additional layer of PPAam was deposited on the C-F coating to eliminate the adverse effect of C-F surface on cytocompatibility. Thus, such a stacked coating imparts MgZnMn with a significantly improved corrosion resistance and promotes cell adhesion and viability. Therefore, the strategy of acetylene-mediated C-F-based coating shows a great potential for tailoring ideal surface functionalities of magnesium-based medical devices.