Yao Changzhuang, Zhang Jingjing, Xue Zihan, Yu Kang, Yu Xinping, Yang Xiaoxiao, Qu Qiulin, Gan Wenbiao, Wang Jingming, Jiang Lei
CAS Key Laboratory of Bio-inspired Materials and Interface Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
Future Technology College, University of Chinese Academy of Sciences, Beijing 100190, P. R. China.
ACS Appl Mater Interfaces. 2021 Jan 27;13(3):4796-4803. doi: 10.1021/acsami.0c20073. Epub 2021 Jan 15.
Hydrodynamic drag not only results in high-energy consumption for water vehicles but also impedes the increase of vehicle speed. The introduction of a low-viscosity gas lubricating film is assumed to be an effective and promising method to reduce hydrodynamic drag. However, the poor stability of the gas film and massive extra energy consumption restricts the practical application of the gas lubricating method. Herein, inspired by the microhairs with low surface energy wax covering the abdomen of water spiders, superhydrophobic sphere surfaces were designed. Attributed to numerous neighboring nanoneedle branches with low surface energy chemicals, an air-entrained cavity with a large surface area was captured and stabilized by the superhydrophobic sphere, changing its shape from a sphere to a streamlined body. The cavity continued attaching to the superhydrophobic sphere without bursting at a depth of 70.0-90.0 cm underwater and reduced the hydrodynamic drag by more than 90%. This work provides a simple, cost-effective, and energy-efficient way to stabilize the underwater gas-liquid interface to achieve a reduction in the hydrodynamic drag.
水动力阻力不仅会导致水上交通工具的高能量消耗，还会阻碍航速的提高。引入低粘度气体润滑膜被认为是一种有效且有前景的降低水动力阻力的方法。然而，气膜稳定性差和大量额外的能量消耗限制了气体润滑方法的实际应用。在此，受水蜘蛛腹部覆盖有低表面能蜡质的微毛启发，设计了超疏水球体表面。由于众多带有低表面能化学物质的相邻纳米针状分支，超疏水球体捕获并稳定了一个具有大表面积的夹带空气的腔体，使其形状从球体变为流线型物体。该腔体在水下70.0 - 90.0厘米深度处持续附着在超疏水球体上而不破裂，并将水动力阻力降低了90%以上。这项工作提供了一种简单、经济高效且节能的方法来稳定水下气液界面，以实现水动力阻力的降低。
