Fish scale inspired design of underwater superoleophobic microcone arrays by sucrose solution assisted femtosecond laser irradiation for multifunctional liquid manipulation

The preparation of superhydrophilic/superoleophilic/underwater superoleophobic surfaces is inspired by natural surfaces such as fish scales possessing hierarchical micro/nanostructures. In this paper, we report the assembly of self-organized hierarchical microcone arrays on a nickel surface by sucrose solution-assisted femtosecond laser irradiation. The processed surface is superhydrophilic (13.47 degrees-4.01 degrees), superoleophilic (7.45 degrees-3.73 degrees), and underwater superoleophobic (135.22 degrees-166.16 degrees) which are comparable to those of fish scales. The wettabilities of the processed surfaces are tunable by adjusting the mass ratio of sucrose to water and pulse energy to control the height (1.62-10.34 mu m) and size (2.1-2.81 mu m) of the microcones. Multifunctional liquid manipulation such as microdroplet transferring, static and dynamic storage, liquid transportation and mixing is demonstrated. Our proposed method features rapidness, simplicity and ease of large-area fabrication, which may find broader applications in many fields such as microfluidic devices, fluidmicroreactors, biomedicine, biomedical scaffolds, and chemical-biological sensors.