Magnetocapillary microrobots: hunting, harvesting and transporting objects at fluid interfaces

磁毛细管微型机器人：在流体界面狩猎、收获和运输物体

• 批准号: 366087427
• 负责人: Professor Dr. Jens Harting
• 金额: --
• 依托单位: Départment de Physique
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/366087427?language=en
• 关键词: Magnetocapillary; microrobots; hunting; harvesting; transporting

A tremendous amount of research was invested recently in the fundamental understanding of biological and artificial microswimmers which has led to a remarkable improvement of our knowledge about the behaviour of biological swimmers such as bacteria or sperm, or artificial systems based for example on colloids which can actively propel due to chemical or thermal gradients.In this project we aim at a fundamental understanding of an alternative class of artificial swimmers which was recently realised experimentally by the group of N. Vandewalle in Liege, Belgium. An assembly of paramagnetic particles trapped at a fluid-fluid interface can be used to create a "magnetocapillary swimmer'': Due to the competition of attractive capillary forces stemming from a deformation of the liquid interface by the gravitation force and repulsive magnetic dipolar interactions in case of an applied static magnetic field, a stable particle assembly emerges. By modulating the external static magnetic field via a smaller linearly-polarized magnetic field, the local equilibirum becomes distorted resulting in a directed motion of the entire particle assembly. We will combine simulations and analytical treatment to study assemblies of paramagnetic particles trapped at a fluid-fluid interface. Our lattice Boltzmann simulations will be based on an already existing solver that can handle two fluids with a well defined surface tension, as well as suspended particles and magnetic interactions. The analytical treatment will be based on the Najafi-Golestanian three-sphere model extended by capillary-, interface- and magnetic forces. A particular attention will be devoted to the influence of the particle shape, size and number, the scalability of the problem between micro- and nano- ranges as well as the design of the magnetic fields on the properties of swimmers. We will explore the controlled swimmer motion for hunting, harvesting and transporting of cargo particles. This opens potential applications of the magneticapillary swimmers as microrobots e.g. for the precise and controllable cleaning of interfaces or the transport and deposition of specific objects. At last we will focus on the interaction of multiple magnetocapillary swimmers: We have already shown that a swimmer reaches its maximum speed at a well defined resonance frequency of the external magentic field. The specific value of this frequency depends not only on the fluid- but also on the particle properties. By varying the size of the particles comprising different swimmers, we will be able to create swarms of microrobots with very complex interactions,but precisely tunable individual motion.

最近，人们在对生物和人工微型游泳器的基本理解上投入了大量的研究，这使得我们对生物游泳器（例如细菌或精子）或基于胶体的人工系统（例如可以由于化学或热梯度而主动推进的胶体）的行为有了显着的了解。在这个项目中，我们的目标是对另类人工游泳器的基本了解，该类最近由该小组通过实验实现 位于比利时列日的 N. Vandewalle。 捕获在流体-流体界面上的顺磁性粒子的集合可用于创建“磁毛细管游动者”：由于在施加静态磁场的情况下，由于重力引起的液体界面变形引起的毛细管吸引力和排斥性磁偶极相互作用的竞争，出现了稳定的粒子集合。通过较小的线性极化磁场调制外部静态磁场 场中，局部平衡变得扭曲，导致整个粒子集合的定向运动。我们将结合模拟和分析处理来研究流体-流体界面处捕获的顺磁性粒子的组装。我们的晶格玻尔兹曼模拟将基于现有的求解器，该求解器可以处理具有明确表面张力的两种流体，以及悬浮颗粒和磁相互作用。分析处理将基于 由毛细管力、界面力和磁力扩展的纳杰菲-戈勒斯坦三球模型。将特别关注颗粒形状、尺寸和数量的影响、微米和纳米范围之间问题的可扩展性以及磁场设计对游泳者特性的影响。我们将探索用于狩猎、收获和运输货物颗粒的受控游泳者运动。 这开启了潜力 磁毛细管游泳器作为微型机器人的应用，例如用于精确、可控地清洁界面或特定物体的运输和沉积。最后，我们将重点关注多个磁毛细管游泳者的相互作用：我们已经证明，游泳者在外部磁场的明确定义的共振频率下达到其最大速度。该频率的具体值不仅取决于流体，还取决于颗粒特性。由 通过改变组成不同游泳者的粒子的大小，我们将能够创建具有非常复杂的相互作用但可精确调节个体运动的微型机器人群。