Studying Liquid-Infused Surfaces with Affordable Surface Features Infiltrated with Various Lubricants from Corrosion, Biofouling, and Fluid Drag Viewpoints

Drag force, corrosion, and biofouling have always been issues that disrupt the reliable operation of systems dealing with fluid flow. Inspired by nature, liquid- or solid-infused surfaces are brand-new surfaces that can address these problems. The present study examines nine comprehensive yet affordable samples with different surface structures, from the nanoscale to the microscale on the aluminum substrate. These surface structures, modified with stearic acid or octadecyltrichlorosilane, are infiltrated with various lubricants. The wetting test shows the magnificent slippery properties of fabricated surfaces with a contact angle hysteresis lower than 10°. The conducted polarization test reveals that the surface structures comprised of aluminum oxide or boehmite have good anti-corrosion properties. Moreover, the higher the viscosity of the lubricant, the better the anti-corrosion abilities. In the anti-bacterial tests, the surfaces possessing a liquid lubricant perform better than those containing solid ones; among them, those with lower viscosities are preferable. The frictional drag test carried out in an aquarium shows that for viscous working fluids, the layered-double hydroxide (LHD) surface containing silicone oil with a viscosity of 5 mPa s could provide a maximum drag reduction of 18%. By increasing the velocity of the surface, the drag reduction ability of LIS reduces. For more viscous lubricants and also solid ones, no appreciable drag reduction is achieved. For less viscous working fluid, however, the anodized surface filled with the same lubricant shows the best results with a maximum drag reduction of 15%. The surface based on LDH also shows good durability in the conducted stability tests.