Mathematical Institute, University of Oxford, Woodstock Road, Oxford, UK.
Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, UK.
J R Soc Interface. 2019 Sep 27;16(158):20190323. doi: 10.1098/rsif.2019.0323. Epub 2019 Sep 4.
We show how anisotropic, grooved features facilitate the trapping and directed transport of droplets on lubricated, liquid-shedding surfaces. Capillary action pins droplets to topographic surface features, enabling transport along the feature while inhibiting motion across (or detachment from) the feature. We demonstrate the robustness of this capillary-based mechanism for directed droplet transport on slippery surfaces by combining experiments on synthetic, lubricant-infused surfaces with observations on the natural trapping surface of a carnivorous pitcher plant. Controlling liquid navigation on synthetic surfaces promises to unlock significant potential in droplet-based technologies. Our observations also offer novel insight into the evolution of the Nepenthes pitcher plant, indicating that the 'pitfall' trapping mechanism is enhanced by the lubricant-infused, macroscopic grooves on the slippery peristome surface, which guide prey into the trap in a way that is more tightly controlled than previously considered.
我们展示了各向异性、有槽特征如何促进受润滑、液滴脱落表面上液滴的捕获和定向传输。毛细作用将液滴固定在地形表面特征上，从而能够沿特征传输，同时抑制跨越（或脱离）特征的运动。我们通过将合成的、注有润滑剂的表面上的实验与肉食性猪笼草的天然捕获表面上的观察相结合，证明了这种基于毛细作用的定向液滴传输机制在光滑表面上的稳健性。控制合成表面上的液体导航有望为基于液滴的技术解锁重大潜力。我们的观察结果也为猪笼草的进化提供了新的见解，表明“陷阱”捕获机制通过在光滑的唇缘表面上注有润滑剂的宏观槽得到增强，这些槽以比以前认为的更严格的方式引导猎物进入陷阱。
