Surface modification and degradation performance of Ag-immobilized polydopamine-coated zinc wires

In this study, silver-containing polydopamine (PDA-Ag) coatings with ~1-5 wt% Ag were successfully deposited on Zn wires via a mussel-inspired, immersion-assisted polymerization approach. Surface characterization confirmed the formation of a continuous, homogeneous, and well-adhered coating layer approximately 720 nm thick. XPS and EDS analyses further verified the uniform distribution of silver nanoparticles within the PDA matrix on the wire surface. Electrochemical investigations demonstrated that the PDA-Ag5 coating exhibited the highest corrosion resistance, as evidenced by a reduced corrosion current density and increased charge-transfer resistance. In contrast, excessive Ag incorporation adversely affected the coating's protective performance. Altogether, the results indicate that controlling Ag content plays a critical role in improving coating uniformity and enhancing the corrosion protection of biodegradable Zn wires.