超疏水摩擦。
Superhydrophobic frictions.
机构信息
Laboratoire d'Hydrodynamique, UMR 7646 du CNRS, École Polytechnique, 91128 Palaiseau Cedex, France.
Physique et Mécanique des Milieux Hétérogènes, UMR 7636 du CNRS, École Supérieure de Physique et de Chimie Industrielles, Paris Sciences et Lettres Research University, 75005 Paris, France.
出版信息
Proc Natl Acad Sci U S A. 2019 Apr 23;116(17):8220-8223. doi: 10.1073/pnas.1819979116. Epub 2019 Apr 5.
Contrasting with its sluggish behavior on standard solids, water is extremely mobile on superhydrophobic materials, as shown, for instance, by the continuous acceleration of drops on tilted water-repellent leaves. For much longer substrates, however, drops reach a terminal velocity that results from a balance between weight and friction, allowing us to question the nature of this friction. We report that the relationship between force and terminal velocity is nonlinear. This is interpreted by showing that classical sources of friction are minimized, so that the aerodynamical resistance to motion becomes dominant, which eventually explains the matchless mobility of water. Our results are finally extended to viscous liquids, also known to be unusually quick on these materials.
与在标准固体上的缓慢行为形成鲜明对比的是，水在超疏水材料上极其具有流动性，例如，在倾斜的防水叶片上，水滴会持续加速。然而，对于更长的基底，水滴会达到一个终端速度，这个速度是由重量和摩擦力之间的平衡产生的，这使我们可以质疑这种摩擦力的性质。我们报告说，力和终端速度之间的关系是非线性的。这可以通过表明经典的摩擦力源被最小化来解释，因此运动的空气动力学阻力变得占主导地位，这最终解释了水无与伦比的流动性。我们的结果最终被扩展到粘性液体，这些液体在这些材料上也以异常快速著称。
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