The ability to manipulate and control active microparticles is essential for designing microrobots for applications. This paper describes the use of electric and magnetic fields to control the direction and speed of induced-charge electrophoresis (ICEP) driven metallic Janus microrobots. A direct current (DC) magnetic field applied in the direction perpendicular to the electric field maintains the linear movement of particles in a 2D plane. Phoretic force spectroscopy (PFS), a phase-sensitive detection method to detect the motions of phoretic particles, is used to characterize the frequency-dependent phoretic mobility and drag coefficient of the phoretic force. When the electric field is scanned over a frequency range of 1 kHz–1 MHz, the Janus particles exhibit an ICEP direction reversal at a crossover frequency at ~30 kH., Below this crossover frequency, the particle moves in a direction towards the dielectric side of the particle, and above this frequency, the particle moves towards the metallic side. The ICEP phoretic drag coefficient measured by PFS is found to be similar to that of the Stokes drag. Further investigation is required to study microscopic interpretations of the frequency at which ICEP mobility switched signs and the reason why the magnitudes of the forward and reversed modes of ICEP are so different.

中文翻译：

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感应电荷电泳金属Janus粒子的频率响应

操纵和控制活性微粒的能力对于设计用于应用的微型机器人至关重要。本文介绍了如何利用电场和磁场来控制感应电荷电泳（ICEP）驱动的金属Janus微型机器人的方向和速度。在垂直于电场的方向上施加的直流（DC）磁场可保持粒子在2D平面中的线性运动。色相力谱（PFS）是一种用于检测电泳粒子运动的相敏检测方法，用于表征频率相关的电泳迁移率和电泳力的阻力系数。当在1 kHz–1 MHz的频率范围内扫描电场时，Janus粒子在〜30 kH的交叉频率下表现出ICEP方向反转，在此交叉频率以下，粒子沿朝着粒子介电面的方向移动，而在此频率之上，粒子朝金属侧朝着运动。发现通过PFS测量的ICEP隐喻阻力系数与斯托克斯阻力相似。需要做进一步的研究来研究ICEP迁移率切换信号的频率的微观解释，以及ICEP正向和反向模式的幅度如此不同的原因。