Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
Phys Rev Lett. 2020 Jan 31;124(4):048002. doi: 10.1103/PhysRevLett.124.048002.
Catalytic colloidal swimmers that propel due to self-generated fluid flows exhibit strong affinity for surfaces. Here, we report experimental measurements of a significant dependence of such microswimmers' speed on the nearby substrate material. We find that speeds scale with the solution contact angle θ on the substrate, which relates to the associated hydrodynamic substrate slip length, as V∝(cosθ+1)^{-3/2}. We show that such dependence can be attributed to osmotic coupling between swimmers and substrate. Our work points out that hydrodynamic slip at nearby walls, though often unconsidered, can significantly impact microswimmer self-propulsion.
由于自生成流体流动而推进的催化胶体游泳者对表面表现出强烈的亲和力。在这里，我们报告了对这种微游泳者速度对附近基底材料的显著依赖性的实验测量。我们发现，速度与基底上的溶液接触角θ成比例，这与相关的流体动力基底滑移长度有关，即 V∝(cosθ+1)^{-3/2}。我们表明，这种依赖性可以归因于游泳者和基底之间的渗透耦合。我们的工作指出，尽管通常不考虑壁附近的流体动力滑移，但它可以显著影响微游泳者的自推进。
