Magnetically controlled ferromagnetic swimmers.
Magnetically controlled ferromagnetic swimmers.
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DOI：
10.1038/srep44142
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发表时间：
2017-03-09
影响因子：
4.6
通讯作者：
Ogrin FY
中科院分区：
文献类型：
--
作者：
Hamilton JK;Petrov PG;Winlove CP;Gilbert AD;Bryan MT;Ogrin FY
微观游泳设备持有承诺，从根本上新的应用在芯片实验室和微流体技术，诊断和药物输送等在本文中，我们展示了一个新的类的自主铁磁游泳设备，驱动和控制的实验验证仅由振荡磁场。这些设备是基于一对相互作用的铁磁颗粒的不同大小和不同的各向异性属性，通过弹性链接连接，并由外部时间相关的磁场驱动。净运动是通过偶极粒子间梯度力、时间相关扭矩和流体动力学耦合的组合产生的。我们调查的动态性能的原型（3.6毫米）的铁磁游泳者在不同粘度的流体作为外部场参数（频率和振幅）的函数，并在很宽的雷诺数范围内表现出稳定的推进。我们发现，游泳的方向有依赖于所施加的外部磁场的频率和振幅，从而在鲁棒控制的速度和方向的推进。这为制造用于需要可靠致动和高度控制的各种技术应用的微型器件铺平了道路。
Microscopic swimming devices hold promise for radically new applications in lab-on-a-chip and microfluidic technology, diagnostics and drug delivery etc. In this paper, we demonstrate the experimental verification of a new class of autonomous ferromagnetic swimming devices, actuated and controlled solely by an oscillating magnetic field. These devices are based on a pair of interacting ferromagnetic particles of different size and different anisotropic properties joined by an elastic link and actuated by an external time-dependent magnetic field. The net motion is generated through a combination of dipolar interparticle gradient forces, time-dependent torque and hydrodynamic coupling. We investigate the dynamic performance of a prototype (3.6 mm) of the ferromagnetic swimmer in fluids of different viscosity as a function of the external field parameters (frequency and amplitude) and demonstrate stable propulsion over a wide range of Reynolds numbers. We show that the direction of swimming has a dependence on both the frequency and amplitude of the applied external magnetic field, resulting in robust control over the speed and direction of propulsion. This paves the way to fabricating microscale devices for a variety of technological applications requiring reliable actuation and high degree of control.