Lubricant-Infused Surfaces for Low-Surface-Tension Fluids: The Extent of Lubricant Miscibility

Abstract

Lubricant-infused surfaces (LISs) and slippery liquid-infused porous surfaces (SLIPSs) have shown remarkable success in repelling low-surface-tension fluids. The atomically smooth, defect-free slippery surface leads to reduced droplet pinning and omniphobicity. However, the presence of a lubricant introduces liquid–liquid interactions with the working fluid. The commonly utilized lubricants for LISs and SLIPSs, although immiscible with water, show various degrees of miscibility with organic polar and nonpolar working fluids. Here, we rigorously investigate the extent of miscibility by considering a wide range of liquid–vapor surface tensions (12–73 mN/m) and different categories of lubricants having a range of viscosities (5–2700 cSt). Using high-fidelity analytical chemistry techniques including X-ray photoelectron spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, and two-dimensional gas chromatography, we quantify lubricant miscibility to parts per billion accuracy. Furthermore, we quantify lubricant concentrations in the collected condensate obtained from prolonged condensation experiments with ethanol and hexane to delineate mixing and shear-based lubricant drainage mechanisms and to predict the lifetime of LISs and SLIPSs. Our work not only elucidates the effect of lubricant properties on miscibility with various fluids but also develops guidelines for developing stable and robust LISs and SLIPSs.

Ultralow Icing Adhesion of a Superhydrophobic Coating Based on the Synergistic Effect of Soft and Stiff Particles

“…When the ice adhesion on surface is small enough, the ice accretion is easily removed from the surface by natural forces, such as wind, vibration, or centrifugal force . Recently, three kinds of surfaces have been developed, including superhydrophobic surfaces, , slippery liquid-infused porous surfaces, , and hydrated or nonfreezing surfaces. , For superhydrophobic surfaces, the reduction of ice adhesion is attributed to a small contact area of ice droplets on the superhydrophobic surface, resulting from a large water contact angle . However, high roughness is usually required to obtain a large water contact angle for superhydrophobic surfaces, which easily leads to an increase of ice adhesion strength (even in the range of 100–500 kPa).…”

Life Span of Slippery Lubricant Infused Surfaces

“…From a theoretical perspective, we estimate the amount of oil retained in the CuO structure by considering that, irrespective of the oil viscosity, the lubricant fills the CuO microstructures (structure height h ≈ 2 μm, solid fraction φ ≈ 0.023). Thus, at initiation of the experiments, the SLIPSs have ≈2 mL/m 2 (≈3.8 g/m 2 ) of lubricant per unit condenser surface area …”

Scalable Slippery Omniphobic Covalently Attached Liquid Coatings for Flow Fouling Reduction

“…At high salinity and high shear forces, the durability of the LIS and SLIPS needs further quantification. Although many studies have quantified the depletion mechanisms of the lubricant in LIS and SLIPS coatings, ,, few have investigated flow conditions . Past work has investigated lubricant loss in a microfluidic channel and a relative flow speed of 8.3 mm/s.…”

“…57,58 few have investigated flow conditions 59. Past work has investigated lubricant loss in a microfluidic channel and a relative flow speed of 8.3 mm/s.…”