Swimmers at interfaces enhance interfacial transport
Swimmers at interfaces enhance interfacial transport
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DOI：
10.1039/d4sm00140k
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发表时间：
2024-06-21
期刊：
影响因子：
3.4
通讯作者：
Stebe，Kathleen J.
中科院分区：
文献类型：
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作者：
Deng，Jiayi;Molaei，Mehdi;Stebe，Kathleen J.
远离平衡的流体界面的行为在自然界和工业中起着核心作用。活跃的游泳者被困在界面上，可以改变流体边界处的输运，这具有深远的意义。游泳者可以被困在不同配置的界面处，并在这些表面粘附状态下持续游泳。细菌的自我推进运动使它们成为理想的模型游泳者，以了解这种影响。我们最近的特点是游泳的界面捕获铜绿假单胞菌PA 01推动模式移动。游泳者通过固定的接触线吸附在界面处，固定了界面处细胞体的角度并限制了它们的运动。因此，游泳者被困在不同配置的界面处，并在这些表面粘附状态下持续游泳。我们观察到，大多数界面捕获的细菌沿沿着圆形路径游动。流体界面通常也形成不可压缩的二维层。这些效应影响游泳者产生的流动。在我们以前的工作中，我们已经可视化的界面流周围的推动细菌和描述的流场使用两个偶极流体动力学模式;一个应力波模式，其对称性不同于散装，和另一个散装模式独特的不可压缩流体界面。在此基础上，本文通过理论分析和实验研究了游泳者诱导的示踪剂位移和游泳者-游泳者对的相互作用。通过模拟和实验比较，确定了多个界面游泳者与圆周运动的设置可以显着提高界面上的示踪剂的运输或促进界面上的其他游泳者的混合。这项研究显示了游泳者在流体界面处的生物混合的重要性，并确定了仿生活性胶体设计中的重要因素，以增强界面传输。
The behavior of fluid interfaces far from equilibrium plays central roles in nature and in industry. Active swimmers trapped at interfaces can alter transport at fluid boundaries with far reaching implications. Swimmers can become trapped at interfaces in diverse configurations and swim persistently in these surface adhered states. The self-propelled motion of bacteria makes them ideal model swimmers to understand such effects. We have recently characterized the swimming of interfacially trapped Pseudomonas aeruginosa PA01 moving in pusher mode. The swimmers adsorb at the interface with pinned contact lines, which fix the angle of the cell body at the interface and constrain their motion. Thus, swimmers become trapped at interfaces in diverse configurations and swim persistently in these surface adhered states. We observe that most interfacially trapped bacteria swim along circular paths. Fluid interfaces also typically form incompressible two-dimensional layers. These effects influence the flow generated by the swimmers. In our previous work, we have visualized the interfacial flow around a pusher bacterium and described the flow field using two dipolar hydrodynamic modes; one stresslet mode whose symmetries differ from those in bulk, and another bulk mode unique to incompressible fluid interfaces. Based on this understanding, swimmer-induced tracer displacements and swimmer–swimmer pair interactions are explored using analysis and experiment. The settings in which multiple interfacial swimmers with circular motion can significantly enhance interfacial transport of tracers or promote mixing of other swimmers on the interface are identified through simulations and compared to experiment. This study shows the importance of biomixing by swimmers at fluid interfaces and identifies important factors in the design of biomimetic active colloids to enhance interfacial transport.