Depletion of lubricant impregnated in a cavity of lubricant-infused surface

Abstract

A lubricant-infused surface (LIS) has been widely studied due to its potential in various industrial fields. However, the outermost lubricant layer of LIS is highly vulnerable to external shear force, which gradually degrades the slippery property. In this study, the shear flow-induced depletion of lubricant impregnated in a single cavity was experimentally investigated. The lubricant-filled three-dimensional cavity was exposed to a laminar channel flow. Temporal variations in the interfacial menisci inside the cavity were directly observed. The result showed that the depletion rate of lubricant is gradually decreased and eventually reaches a quasi-steady state after a long lapse of time. A large-scale vortex is formed near the lubricant meniscus and largely weakens the shear stress exerted on the meniscus. The formation of a large-scale vortex dramatically slows down the depletion rate of the impregnated lubricant. In addition, the effect of cavity geometry on the depletion of the lubricant impregnated in a biomimetic LIS was examined. The results revealed that a cavity with a smaller opening ratio (r/R) has better sustainability and less lubricant depletion. The present results would provide valuable insight into the design of a robust LIS system for effective and sustainable drag reduction and other applications.

Fluid manipulationviamultifunctional lubricant infused slippery surfaces: principle, design and applications

“…In 2021, Kim et al explored the loss of lubricant in the SLIPS porous substrate under the impact of continuous water flow. 134 The loss rate of lubricant will increase at first and then decrease until the lubricant is completely lost. Through this experiment, they found that the spherical cavity has better performance in retaining the lubricant because this shape can reduce the shear stress caused by water flow.…”

Recent advances of slippery liquid-infused porous surfaces with anti-corrosion

“…A low-surface-energy and low-viscosity lubricant is used to fill the surface micro/nano-pore structure to form a lubricant layer of SLIPS to make the surface molecularly smooth, which is unable to provide an effective adsorption point for contaminants or bacteria on the surface 44 (Fig. 5(b)) Tables 1 and 2.…”

Characterization of the Liquid–Lubricant Interface in a Dovetail Cavity for a Viscous Laminar Flow

“…23 Partially filled spherical cavities with lubricant exhibited a significant resistance to depletion with time compared to a cylindrical groove. 24 Thus, there is a need to further examine different groove geometries.…”

“…However, most of the studies considered the meniscus to be flat, which appears to be unrealistic. − Considering the interfacial tension effect and flow dynamics at the interface, for rectangular grooves, narrower and deeper grooves aid in superior resistance to lubricant depletion with a larger L s . Partially filled spherical cavities with lubricant exhibited a significant resistance to depletion with time compared to a cylindrical groove . Thus, there is a need to further examine different groove geometries.…”