Directed Motion of Metallodielectric Particles by Contact Charge Electrophoresis
Directed Motion of Metallodielectric Particles by Contact Charge Electrophoresis
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DOI：
10.1021/acs.langmuir.6b03361
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发表时间：
2016-12-13
期刊：
影响因子：
3.9
通讯作者：
Bishop, Kyle J. M.
中科院分区：
文献类型：
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作者：
Dou, Yong;Cartier, Charles A.;Bishop, Kyle J. M.
通过接触电荷电泳法(CCEP)研究了金属介质Janus粒子在两个平行电极之间的运动动力学。CCEP使用恒定电压反复充电和激励介电流体中的导电粒子，导致电极之间的快速振荡运动。除了粒子振荡，我们还发现微米尺度的贾纳斯粒子以高速(高达600微米/S)垂直于场运动，并且移动距离很大。我们表征了粒子的运动，并提出了一种基于电极表面电荷转移后粒子旋转诱导平移的机制。推进机制得到了揭示其旋转运动的荧光粒子实验的支持，也得到了捕捉到相关静电学和流体动力学的CCEP动力学模拟的支持。我们还表明，多个粒子之间的相互作用可以导致排斥、吸引和/或协同运动，这取决于各个粒子振荡器的位置和相位。我们的结果展示了如何利用粒子的不对称性来指导由CCEP提供动力的活性胶体的运动。
We investigate the dynamics of metallodielectric Janus particles moving via contact charge electrophoresis (CCEP) between two parallel electrodes. CCEP uses a constant voltage to repeatedly charge and actuate conductive particles within a dielectric fluid, resulting in rapid oscillatory motion between the electrodes. In addition to particle oscillations, we find that micrometer-scale Janus particles move perpendicular to the field at high speeds (up to 600 mu m/s) and over large distances. We characterize particle motions and propose a mechanism based on the rotation-induced translation of the particle following charge transfer at the electrode surface. The propulsion mechanism is supported both by experiments with fluorescent particles that reveal their rotational motions and by simulations of CCEP dynamics that capture the relevant electrostatics and hydrodynamics. We also show that interactions among multiple particles can lead to repulsion, attraction, and/or cooperative motions depending on the position and phase of the respective particle oscillators. Our results demonstrate how particle asymmetries can be used to direct the motions of active colloids powered by CCEP.