Modular phoretic micro-swimmers: from individual minimal swimmers to multi-component schools

在这个项目中，我们研究了模块化的微游泳者和密切相关的现象。模块化微型游泳者从不活跃的组件自发组织，能够定向运动和货物运输。我们的模块化方法允许灵活的组合和优化组件，以提高整体性能。使用真实空间视频显微镜作为主要研究工具，迄今为止的实验仅限于准二维情况。我们研究了电渗透泵送、最小模块游泳和单组分学校教育，以获得和描述丰富的现象学。这些现象是在系统的、可控的实验边界条件变化下研究的，其结果可以参数化。这为与SPP内的几个理论项目密切合作开发定性模型提供了坚实的定量数据基础。然而，它也表明，进一步的进展将提供对包括溶剂在内的所有组分运动的完整3D描述的扩展。这将在第二个筹资期间进行尝试。我们将实施三维全息跟踪实验，并利用它来继续和扩展我们对游泳和学校教育的研究。这个实验将产生完整的3D溶剂流动，从而促进最小游泳的定量建模，包括像下坡游泳这样的高级问题。此外，许多有趣的高流量情况将变得非常详细。这包括多层蜂群和多组分蜂群中三维对流结构的形成。此外，溶剂的3D跟踪将有力地支持转向的实施。和以前一样，高流量现象和新的游泳者类型也将被全面记录和系统地描述。在这些数据的基础上，与理论的密切合作可以继续和扩展，以接近对模块化藻微游泳和相关现象的精确定量理解的总体目标。

In this project we investigate modular phoretic micro-swimmers and closely related phenomena. Modular micro-swimmers self-organize spontaneously from inactive components and are capable of directed motion and cargo transport. Our modular approach allows for a flexible composition and optimization of components in order to improve overall performance. Using real space video-microscopy as main tool of investigation, experiments have so far been restricted to quasi 2D situations. We studied electro-osmotic pumping, minimal modular swimming and single component schooling to obtain and describe a rich phenomenology. These phenomena were investigated under systematic and controlled variation of experimental boundary conditions and the resulting behavior could be parameterized. This returned a solid quantitative data base for the development of qualitative models in close collaboration with several theoretical projects within this SPP. However, it also showed that further progress will afford an extension to a full 3D description of the motion of all components including the solvent. This shall be attempted in the second funding period. We will implement a three dimensional holographic tracking experiment and use it to continue and extend our investigations of swimming and schooling. This experiment will yield the full 3D solvent flows and thus facilitate a quantitative modeling of minimal swimming including advanced issues like downhill swimming. In addition, a number of interesting high flow situations will become accessible in great detail. These include multi-layered swarms and the formation of 3D convection structures in multi-component swarms. Moreover, 3D tracking of the solvent will strongly support the implementation of steering. As before, also high flow phenomena and novel swimmer types shall be comprehensively documented and systematically characterized. Based on these data the close collaboration with theory can be continued and extended to approach the overall goal of a refined quantitative understanding of modular phoretic micro-swimming and related phenomena.