Open AccessJournal Article
Condensation on Slippery Asymmetric Bumps
TLDR
A conceptually different design approach is presented—based on principles derived from Namib desert beetles, cacti, and pitcher plants—that synergistically combines these aspects of condensation and substantially outperforms other synthetic surfaces.Abstract:
Controlling dropwise condensation is fundamental to water-harvesting systems, desalination, thermal power generation, air conditioning, distillation towers, and numerous other applications. For any of these, it is essential to design surfaces that enable droplets to grow rapidly and to be shed as quickly as possible. However, approaches based on microscale, nanoscale or molecular-scale textures suffer from intrinsic trade-offs that make it difficult to optimize both growth and transport at once. Here we present a conceptually different design approach—based on principles derived from Namib desert beetles, cacti, and pitcher plants—that synergistically combines these aspects of condensation and substantially outperforms other synthetic surfaces. Inspired by an unconventional interpretation of the role of the beetle’s bumpy surface geometry in promoting condensation, and using theoretical modelling, we show how to maximize vapour diffusion fluxat the apex of convex millimetric bumps by optimizing the radius of curvature and cross-sectional shape. Integrating this apex geometry with a widening slope, analogous to cactus spines, directly couples facilitated droplet growth with fast directional transport, by creating a free-energy profile that drives the droplet down the slope before its growth rate can decrease. This coupling is further enhanced by a slippery, pitcher-plant-inspired nanocoating that facilitates feedback between coalescence-driven growth and capillary-driven motion on the way down. Bumps that are rationally designed to integrate these mechanisms are able to grow and transport large droplets even against gravity and overcome the effect of an unfavourable temperature gradient. We further observe an unprecedented sixfold-higher exponent of growth rate, faster onset, higher steady-state turnover rate, and a greater volume of water collected compared to other surfaces. We envision that this fundamental understanding and rational design strategy can be applied to a wide range of water-harvesting and phase-change heat-transfer applications.read more
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References
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Journal ArticleDOI
Electromigration-triggered programmable droplet spreading
TL;DR: In this paper, the authors proposed a temporospatial control of droplet spreading by mediating current intensity via the electromigration of oxygen adatom, which can be used to program the spreading behavior of droplets.
Journal ArticleDOI
Bioinspired micro- and nanostructures used for fog harvesting
Hongwen Sun,Yiwen Song,Bo Zhang,Yunzhe Huan,Chenyang Jiang,Heyu Liu,Tingting Bao,Shengxin Yu,Haibin Wang +8 more
TL;DR: In this article, various bioinspired surfaces for water harvesting are reviewed including plants (cactus, lotus, rice, pitaya, Cotula fallax, Eremopyrum orientale, Salsola crassa, and Gladiolus dalenii) from the aspects of fabrication processes and water collecting efficiency.
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