Shen Chong, Jiang Zhiyu, Li Lanfang, Gilchrist James F, Ou-Yang H Daniel
Department of Physics, Lehigh University, Bethlehem, PA 18015, USA.
Emulsion Polymers Institute, Lehigh University, Bethlehem, PA 18015, USA.
Micromachines (Basel). 2020 Mar 24;11(3):334. doi: 10.3390/mi11030334.
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.
对于设计用于各种应用的微型机器人而言，操纵和控制活性微粒的能力至关重要。本文描述了利用电场和磁场来控制感应电荷电泳（ICEP）驱动的金属双面微型机器人的方向和速度。在垂直于电场的方向上施加直流（DC）磁场，可使粒子在二维平面内保持直线运动。电泳力谱（PFS）是一种用于检测电泳粒子运动的相敏检测方法，用于表征电泳力的频率依赖性电泳迁移率和阻力系数。当电场在1 kHz - 1 MHz的频率范围内扫描时，双面粒子在约30 kHz的交叉频率处表现出ICEP方向反转。低于此交叉频率时，粒子向粒子的电介质侧移动，高于此频率时，粒子向金属侧移动。通过PFS测量的ICEP电泳阻力系数与斯托克斯阻力系数相似。需要进一步研究以探讨ICEP迁移率切换符号的频率的微观解释以及ICEP正向和反向模式大小差异如此之大的原因。
