Lubricant-infused micro/nano-structured surfaces with tunable dynamic omniphobicity at high temperatures

Abstract

Omniphobic surfaces that can repel fluids at temperatures higher than 100 °C are rare. Most state-of-the-art liquid-repellent materials are based on the lotus effect, where a thin air layer is maintained throughout micro/nanotextures leading to high mobility of liquids. However, such behavior eventually fails at elevated temperatures when the surface tension of test liquids decreases significantly. Here, we demonstrate a class of lubricant-infused structured surfaces that can maintain a robust omniphobic state even for low-surface-tension liquids at temperatures up to at least 200 °C. We also demonstrate how liquid mobility on such surfaces can be tuned by a factor of 1000.

Transparent antifouling material for improved operative field visibility in endoscopy

“…Analogous oscillatory behavior in visualization is also found for the higher viscosity lubricants ( Fig. 1 E and F), but temporary visual aberrations become more pronounced because the contaminating liquid is less mobile due to viscous dissipation in the lubricant layer (23,33).…”

Fabrics coated with lubricated nanostructures display robust omniphobicity

“…Lubricant-infused nano-/micro-structured surfaces have been recently introduced as an alternative approach to omniphobic materials [1][2][22][23][25][26][27][28][29][30]. The key feature of this design is the anchoring of a lubricating liquid into a chemically similar, texturized solid substrate, thus creating a stable, smooth, defect-free and liquid-repellent interface.…”

“…Low-surface-tension liquids under pressure can penetrate the air pockets of lotus-inspired materials but they will not displace the stable lubricant interface. SLIPS can also be made optically transparent, self-healing, and tolerant to drastic changes in pressure, temperature, and pH [1,23,[28][29][30]. A suitable substrate for SLIPS must have micro-/nanoscale porosity with a strong chemical affinity for the lubricating film to ensure a complete wetting of the texturized solid by the lubricant and its stable retention in the porous network; surface area is crucial for increased capillarity and promotion of lubricant wicking, and chemical affinity provides strong adhesion to lock the lubricant onto the surface and prevent foreign materials from displacing the lubricant.…”

Fabrication of high aspect ratio silicon micro-/nano-pore arrays and surface modification aiming at long lifetime liquid-infused-type self-cleaning function

“…The first requirement is satisfied by using fine structures (large surface area), low surface energy layer (hydrophobicity, good chemical affinity) and the low surface tension liquid for easy infusion. Perfuoropolyether (PFPE, F-(CF(CF3)-CF2-O)n-CF2CF3), a lubricant of vacuum pumps, with low surface tension and immiscibility with many kinds of liquids, is usually used to satisfy the second requirement (Wong et al, 2011, Daniel et al, 2013, Zhang et al, 2014. The surface energy balance at the interface of the lubricant, foreign liquids, fine structures, and air is critical for the third requirement.…”

“…However, evaluation of the long-term performance has been hindered by the absence of a unified definition of lifetime of liquid-infused-type self-cleaning function, the absence of a standardized test method and having different criteria for the evaluation. The liquid-infused surfaces operated against various stimuli such as high shear stress to remove the lubricant (Kim et al, 2013), high temperature to increase the evaporation rate of lubricant (Wong et al, 2011) or to reduce the surface tension of the foreign liquids (Daniel et al, 2013). Then functional comparison or changing of SA is usually used as the criterion to conclude the function has preserved for long time.…”