Surface texturized graphene oxide coating on Ti6Al4V by integrated femtosecond laser

Abstract

Graphene oxide (GO) coating has the advantages of high specific surface area and easy functional modification, and has great application prospects in orthopedic implants. However, its poor osteogenic properties limit its application and need to be further improved. Studies have shown that periodic nanostreaks on the surface of long bone during development are beneficial to improve osteogenic properties and promote periosteal tissue formation. Therefore, based on the idea of duplex modification combining surface coating and surface texture technology, this paper uses femtosecond laser to construct periodic structure on the surface of GO coating on titanium alloy substrate, and controls the surface micro-nano morphology and chemical composition of GO coating. The surface morphology, crystal structure and chemical composition were characterized and confirmed by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and three-dimensional laser confocal microscopy. Using this technique, a uniform and complete GO coating is prepared and periodic nanofringes (i.e. laser-induced periodic surface structures) are formed on its surface under laser action without damaging the substrate material. In the case of a scan speed of 0.005m/s, the period changes from 924 nm to 442 nm when the laser power is increased from 0.4 W to 8W. Raman spectrum results show that the degree of graphitization increases and the disorder decreases under laser action. XPS and FTIR confirmed the removal of oxygen-containing groups and the conversion of Csp³ to Csp² in the GO coating.