Delayed lubricant depletion of slippery liquid infused porous surfaces using precision nanostructures

Laney, S. K., Michalska, M., Li, T., Ramirez, F. V., Portnoi, M., Oh, J., Thayne, I. G. , Parkin, I. P., Tiwari, M. K. and Papakonstantinou, I. (2021) Delayed lubricant depletion of slippery liquid infused porous surfaces using precision nanostructures. Langmuir, 37(33), pp. 10071-10078. (doi: 10.1021/acs.langmuir.1c01310) (PMID:34286995)

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Abstract

Slippery liquid infused porous surfaces (SLIPS) are an important class of repellent materials, comprising micro/nanotextures infused with a lubricating liquid. Unlike superhydrophobic surfaces, SLIPS do not rely on a stable air–liquid interface and thus can better manage low surface tension fluids, are less susceptible to damage under physical stress, and are able to self-heal. However, these collective properties are only efficient as long as the lubricant remains infused, which has proved challenging. We hypothesized that, in comparison to a nanohole and nanopillar morphology, the “hybrid” morphology of a hole within a nanopillar, namely a nanotube, would be able to retain and redistribute lubricant more effectively, owing to capillary forces trapping a reservoir of lubricant within the tube, while lubricant between tubes can facilitate redistribution to depleted areas. By virtue of recent fabrication advances in spacer defined intrinsic multiple patterning (SDIMP), we fabricated an array of silicon nanotubes and equivalent arrays of nanoholes and nanopillars (pitch, 560 nm; height, 2 μm). After infusing the nanostructures (prerendered hydrophobic) with lubricant Krytox 1525, we probed the lubricant stability under dynamic conditions and correlated the degree of the lubricant film discontinuity to changes in the contact angle hysteresis. As a proof of concept, the durability test, which involved consecutive deposition of droplets onto the surface amounting to 0.5 L, revealed 2-fold and 1.5-fold enhancements of lubricant retention in nanotubes in comparison to nanopillars and nanoholes, respectively, showing a clear trajectory for prolonging the lifetime of a slippery surface.

Item Type:Articles
Additional Information:The work was conducted in the framework of the European Research Council (ERC) starting grant IntelGlazing, Grant No. 679891. We are grateful to Lloyd’s Register Foundation for an International Consortium of Nanotechnology (ICON) research grant and UCL BEAMS School for a Ph.D. studentship. Funding by the ERC grant NICEDROPS, Grant No. 714712, and MKT’s Royal Society Wolfson Fellowship is also gratefully acknowledged.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Thayne, Prof Iain
Authors: Laney, S. K., Michalska, M., Li, T., Ramirez, F. V., Portnoi, M., Oh, J., Thayne, I. G., Parkin, I. P., Tiwari, M. K., and Papakonstantinou, I.
College/School:College of Science and Engineering > School of Engineering
Journal Name:Langmuir
Publisher:American Chemical Society
ISSN:0743-7463
ISSN (Online):1520-5827
Published Online:21 July 2021

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