Wetting ridge migration and oil wicking during condensation frosting on oil-impregnated surfaces*

Frosting/icing has adverse impacts on various industries including transportation and power generation. Conventional ice removal methods using chemical, thermal, and mechanical techniques are time-consuming, energy-intensive, costly, and environmentally harmful. Recently, nature-inspired micro-nanostructured surfaces infused with lubricant oil, referred to as slippery liquid-infused porous surfaces (SLIPS) or liquid-infused surfaces (LIS), have shown great promise not only in delaying frosting/icing but in reducing ice adhesion strength when compared to traditional lotus-leaf-inspired hierarchical surfaces. However, before we can adopt these semi-liquid semi-solid composite surfaces for anti-icing applications, the problem of oil depletion in the form of wetting ridge migration needs to be resolved. In this work, we experimentally characterize and model the wetting ridge migration, oil wicking, and oil depletion rate when water droplets freeze on textured oil-impregnated surfaces. The insights gained from this work guide the rational design of oil-impregnated surfaces that can reduce and potentially eliminate oil loss; a major bottleneck that inhibited the use of oil-impregnated surfaces in industrial applications.