Increase of one-to-one particle encapsulation yield using dielectrophoretic alignment technique with boxcar-type electrodes
Increase of one-to-one particle encapsulation yield using dielectrophoretic alignment technique with boxcar-type electrodes
复制标题
DOI：
10.1299/transjsme.21-00300
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
K. Mabuchi;K. Tatsumi;R. Kuriyama;K. Nakabe
中科院分区：
文献类型：
--
作者：
K. Mabuchi;K. Tatsumi;R. Kuriyama;K. Nakabe
我们开发了一种技术，通过应用使用棚车型电极的介电泳颗粒排列技术，可以提高一对一颗粒封装的产量。当粒子在电极区域流动时，棚车型电极产生的介电泳力使粒子周期性地加速和减速。此外，介电泳力以恒定频率开启和关闭。在空间和时间上周期性地施加在粒子上的力可以使它们沿流向以均匀的间隔排列。在本研究中，棚车型电极安装在产生油包水液滴的流聚焦通道上游区域的微通道中。通过将产生介电泳力的施加电压的开关周期调整为液滴生成的周期，可以将每个颗粒单独封装在液滴中。首先基于一维模型描述了使用周期性力的粒子排列原理。然后讨论了流聚焦通道中的流动结构和液滴生成特性与流体表面张力和壁润湿性的关系。我们测量了在棚车电极区域中流动的颗粒的速度分布，以评估液滴生成对颗粒运动和对准性能的影响。结果表明，颗粒可以在液滴产生引起的脉动流中排列，并且每个颗粒可以被封装在不同的液滴中。通过测量含有特定数量颗粒的液滴的概率函数进一步证明了这一点，结果表明，在颗粒数密度为0.4的研究条件下，可以实现100%的一对一颗粒封装。此外，与随机供应颗粒的情况相比，吞吐量增加了 46%。
We developed a technique which can increase the yield of one-to-one particle encapsulation by applying the dielectrophoretic particle alignment technique using boxcar-type electrodes. Dielectrophoretic force generated by the boxcar-type electrodes accelerate and decelerate the particles periodically as they flow in the electrode region. Further, the dielectrophoretic force is turned on and off at constant frequency. The force exerted on the particle periodically over space and time can align them in the streamwise direction with even interval. In this study, the boxcar-type electrodes were installed in the microchannel in the region upstream of the flow-focusing channel in which the water-in-oil droplets were generated. By adjusting the on-off period of the applied voltage generating the dielectrophoretic force to the period of the droplet generation, each particle could be separately encapsulated in the droplets. The principle of particle alignment using periodic force was first described based on a one-dimensional model. The flow structure and the characteristics of the droplet generation in the flow-focusing channel was then discussed in relation to the surface tension of the fluids and the wettability of the wall. We measured the velocity distribution of the particles flowing in the boxcar electrode region to evaluate the effects of the droplet generation on the motion of the particles and the alignment performance. The results showed that the particle could be aligned in the fluctuating flow caused by the droplet generation, and each particle can be encapsulated in different droplets. This was further demonstrated by measuring the probability function of the droplets containing specific number of particles, which showed that 100% yield of one-to-one particle encapsulation can be achieved under the investigated condition of particle number density of 0.4. Moreover, the throughput increased 46% compared to the case of having the particles supplied randomly.