Jiang Tianyi, Jia Yankai, Sun Haizhen, Deng Xiaokang, Tang Dewei, Ren Yukun
School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China.
State Key Laboratory of Robotics and System, Harbin Institute of Technology, West Da-Zhi Street 92, Harbin 150001, Heilongjiang, China.
Micromachines (Basel). 2020 Dec 17;11(12):1121. doi: 10.3390/mi11121121.
Microfluidic technologies have enabled generation of exquisite multiple emulsion droplets, which have been used in many fields, including single-cell assays, micro-sized chemical reactions, and material syntheses. Electrical controlling is an important technique for droplet manipulation in microfluidic systems, but the dielectrophoretic behaviors of multiple emulsion droplets in electrical fields are rarely studied. Here, we report on the dielectrophoresis response of double emulsion droplets in AC electric fields in microfluidic channel. A core-shell model is utilized for analyzing the polarization of droplet interfaces and the overall dielectrophoresis (DEP) force. The water-in-oil-in-water droplets, generated by glass capillary devices, experience negative DEP at low field frequency. At high frequency, however, the polarity of DEP is tunable by adjusting droplet shell thickness or core conductivity. Then, the behavior of droplets with two inner cores is investigated, where the droplets undergo rotation before being repelled or attracted by the strong field area. This work should benefit a wide range of applications that require manipulation of double emulsion droplets by electric fields.
微流控技术已能够生成精致的多重乳液液滴，这些液滴已被应用于许多领域，包括单细胞分析、微型化学反应和材料合成。电控制是微流控系统中液滴操纵的一项重要技术，但多重乳液液滴在电场中的介电泳行为鲜有研究。在此，我们报道了微流控通道中双乳液液滴在交流电场中的介电泳响应。采用核壳模型分析液滴界面的极化和整体介电泳（DEP）力。由玻璃毛细管装置产生的水包油包水乳滴在低场频率下经历负介电泳。然而，在高频下，通过调节液滴壳层厚度或核的电导率可使介电泳的极性可调。然后，研究了具有两个内核的液滴的行为，其中液滴在被强场区排斥或吸引之前会发生旋转。这项工作将有益于广泛的需要通过电场操纵双乳液液滴的应用。
