Multifunctional surface of titanium alloy with dual-scale hierarchical micro/nanostructures fabricated by femtosecond laser processing

A facile and flexible method was introduced to fabricate a multifunctional surface with various micro/nanostructures. Ripples and hierarchical micro/nano conical structure arrays were patterned on titanium alloy sheets by adjusting the parameters of femtosecond laser, realizing the controllable processing of surface micro/nanostructures. After further chemical modification to lower surface free energy, the titanium alloy sheets covered with hierarchical micro/nano conical structure arrays and ripples were superhydrophobic and hydrophobic. The surfaces processed by femtosecond laser showed excellent durability and stability after a 15-day contact angle test and sandpaper friction measurement. Finally, three-dimensional macro devices with hierarchical micro/nanostructures were prepared by femtosecond laser, which has excellent self-cleaning performance. In addition, the light absorption efficiency of the fabricated titanium alloy sheets was much higher than that of the bare sheet at a wavelength range of 200–2500 nm, indicating the excellent light trapping ability of the fabricated surfaces. These results imply the potential applications of the fabricated hierarchical micro/nanostructures in self-cleaning and light absorption.