Green Fabrication of Anti-friction Slippery Liquid-Infused Metallic Surface with Sub-millimeter-Scale Asymmetric Bump Arrays and Its Application

In this work, we present a simple technique for green fabrication of slippery liquid-infused surface (SLIS) with anti-friction property on various metallic substrates using wire electrical discharge machining. Micro-crater structures were successfully obtained, and the surface had excellent liquid-repellent property after modification and infusion of silicone oil. A wide range of liquids including water, juice, coffee, tea, vinegar, albumin, glycerol, and ketchup could easily slid down the surface tilted at an angle of 10° without leaving any trace. The influences of the number of cutting step on the morphology and wettability of the surface were studied comprehensively. Further, the tribological properties of the surface were analyzed and the results showed that the SLIS had a decrease of 73.2% in friction coefficient as compared to that of the smooth surface. By studying the morphology of the worn surfaces, it is found that the SLIS had slight abrasive wear behavior. To demonstrate the precision processing ability of this technology, we fabricated slippery sub-millimeter-scale asymmetric bump arrays, and the experiment results showed that the asymmetric bump arrays had excellent water harvesting ability at low temperatures. This kind of environment-friendly precision machining technology will promote the practical applications of metallic functional materials.