Gauthier Anaïs, Lajoinie Guillaume, Snoeijer Jacco H, van der Meer Devaraj
Physics of Fluids group and Max Plank Center Twente, Mesa + Institute and Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics and Max Plank Center Twente for Complex Fluid Dynamics, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands.
Soft Matter. 2020 Apr 29;16(16):4043-4048. doi: 10.1039/c9sm02363a.
Drops deposited on an evaporating liquid bath can be maintained in an inverse Leidenfrost state by the vapor emanating from the bath, making them levitate and hover without effective friction. These perfectly non-wetting droplets create a depression in the liquid interface that sustains their weight, which generates repellent forces when they approach a meniscus rising against a wall. Here, we study this reflection in detail, and show that frictionless Leidenfrost drops are a simple and efficient tool to probe the shape of an unknown interface. We then use the menisci to control the motion of the otherwise elusive drops. We create waveguides to direct and accelerate them and use parabolic walls to reflect and focus them. This could be particularly beneficial in the scale up of droplet cryopreservation processes: capillary interactions can be used to transport, gather and collect vitrified biological samples in absence of contact and contamination.
沉积在蒸发液池上的液滴可通过液池散发的蒸汽维持在逆莱顿弗罗斯特状态，使其悬浮且无有效摩擦地悬停。这些完全不润湿的液滴在液体界面上形成一个凹陷以支撑其重量，当它们靠近靠壁上升的弯月面时会产生排斥力。在此，我们详细研究这种反射，并表明无摩擦的莱顿弗罗斯特液滴是探测未知界面形状的一种简单而有效的工具。然后我们利用弯月面来控制原本难以捉摸的液滴的运动。我们创建波导来引导和加速它们，并使用抛物面壁来反射和聚焦它们。这在扩大液滴冷冻保存过程规模方面可能特别有益：毛细管相互作用可用于在无接触和无污染的情况下运输、聚集和收集玻璃化的生物样本。
