Durability of Slippery Liquid-Infused Surfaces: Challenges and Advances

Slippery liquid-infused porous surfaces (SLIPS) have emerged as a unique approach to creating surfaces that can resist fouling when placed in contact with aqueous media, organic fluids, or biological organisms. These surfaces are composed of essentially two components: a liquid lubricant that is locked within the protrusions of a textured solid due to capillarity. Drops, immiscible to the lubricant, exhibit high mobility and very-low-contact-angle hysteresis when placed on such surfaces. Moreover, these surfaces are shown to resist adhesion to a wide range of fluids, can withstand high pressure, and are able to self-clean. Due to these remarkable properties, SLIPS are considered a promising candidate for applications such as designing anti-fouling and anti-corrosion surfaces, drag reduction, and fluid manipulation. These collective properties, however, are only available as long as the lubricant remains infused within the surface protrusions. A number of mechanisms can drive the depletion of the lubricant from the interior of the texture, leading to the loss of functionality of SLIPS. Lubricant depletion is one challenge that is hindering the real-world application of these surfaces. This review mainly focuses on the studies conducted in the context of enhancing the lubricant retention abilities of SLIPS. In addition, a concise introduction of wetting transitions on structured as well as liquid-infused surfaces is given. We also discuss, briefly, the mechanisms that are responsible for lubricant depletion.