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 microcones arrays on nickel surface by sucrose solution-assisted femtosecond laser irradiation. The processed surface is superhydrophilic (13.47 o~4 .01 o ), superoleophilic (7.45 o~3 .73 o ), and underwater superoleophobic (135.22 o~1 66.16 o ), which are comparable to that of the fish scales. The wettabilities of the processed surfaces are tunable by adjusting the mass ratio of the sucrose to water and pulse energy to control the height (1.62~10.34 µm) and size (2.1~2.81 µm) of the microcones. Multifunctional liquid manipulation such as microdroplet transferring, static and dynamic storage, liquid transportation and mixing are demonstrated. Our proposed method features rapidness, simplicity and easiness of large-area fabrication, which may find broader applications in many fields such as microfluidic devices, fluid microreactors, biomedicine, biomedical scaffold, and chemical-biological sensors.-3 -preparing underwater superoleophobic surfaces by femtosecond laser microfabrication on Ti materials. As a kind of important ferromagnetic metal, nickel shows outstanding optical, catalytic, electrical, and superior resistant characteristics to corrosion, which makes it widely applicable in electronics, [19] nickel-batteries, [20] alloy, [21] and chemical catalyst. [22] However, the present fabrication on nickel material using femtosecond laser microfabrication and studying the underwater superoleophobicity are still few. Therefore, it is of great interests to produce underwater superoleophobic surfaces on nickel substrates, and study their functions and potential applications.Here, we demonstrate a facile and rapid method to fabricate large-area microcones arrays by one-step femtosecond laser irradiation on nickel targets in sucrose solutions. The prepared surfaces are superhydrophilic in air and superoleophobic in water. It is indicated that the height and size are tunable by controlling the ratio of the sucrose to the water in the solution and the laser pulse energy, leading to controllable wettabilities for water and oil. Furthermore, these processed surfaces covered with microcones arrays exhibit multiple functions, which can be used in microfluidic devices, fluid microreactors, biomedicine, biomedical scaffold, chemical, and biological sensors.
Experimental SectionMaterials: Nickel sheets with a purity of 99.99% were purchased from New Metal Material Tech. Co., Ltd., Beijing, China. The oil used in our experiment is 1, 2dichloroethane, and the chemical formula was C 2 H 4 Cl 2 . The sucrose (chemical formula is C 12 H 22 O 11 and the relative molecular mass is 342.3), milk (the color is white) and the red ink are purchased from supermarket. The sucrose solution is prepared by dissolving sucrose with a certain mass into 100g distilled water, and the mass ratio ran...