Surface modification of Ti6Al4V alloy by polydopamine grafted GO/ZnO nanocomposite coating

Abstract

Implant prosthetics composed of the Ti6Al4V alloy are prone to releasing harmful metal ions into surrounding tissue, as well as causing bacterial infections, in the human body. In order to address these problems, the surface of the Ti6Al4V alloy was grafted with polydopamine (PDA) and then coated with a graphene oxide/zinc oxide (GO/ZnO) nanocomposite coating by both hydrothermal growth and drop-casting methods. The phase composition, microstructure, wettability , corrosion resistance , and antibacterial activities of the nanocomposite coatings at each stage of growth were systematically analyzed. The results showed that the ZnO/PDA nanocoating and GO/ZnO/PDA nanocomposite coating demonstrated excellent wettability properties as well as antibacterial activities against Escherichia coli and Staphylococcus aureus . The introduction of GO into the ZnO/PDA nanocoating enhanced the ability of the nanocoating, which synergistically enabled the mineralization of hydroxyapatite onto the nanocomposite coating while immersed in a simulated body fluid (SBF) solution. The GO/ZnO/PDA nanocomposite coating also improved the corrosion resistance of Ti6Al4V substrate in Ringer's solution by preventing the diffusion of corrosive electrolyte ions through the coating to the Ti6Al4V substrate. • PDA pretreatment of Ti6Al4V promoted strong binding between ZnO and substrate. • GO served as a barrier blocked corrosion ions in the corrosion process. • GO/ZPT coating showed excellent corrosion resistance, and antibacterial activity.