Electrothermal enrichment of submicron particles in an insulator-based dielectrophoretic microdevice
Electrothermal enrichment of submicron particles in an insulator-based dielectrophoretic microdevice
复制标题
基于绝缘体的介电泳微型器件中亚微米颗粒的电热富集
DOI：
10.1002/elps.201700342
复制
发表时间：
2018-03-01
期刊：
影响因子：
2.9
通讯作者：
Xuan, Xiangchun
中科院分区：
文献类型：
--
作者：
Kale, Akshay;Song, Le;Xuan, Xiangchun
基于绝缘体的介电电泳（iDEP）利用通道内的障碍物和柱等来产生用于各种粒子操纵的电场梯度。然而，这种绝缘结构的存在也放大了其周围流体中的焦耳加热，导致温度梯度和湍流。这些焦耳热效应先前已被证明削弱介电泳聚焦和捕获的微米级和纳米级颗粒。我们发现，湍流涡旋能够夹带亚微米颗粒的局部富集附近的绝缘尖端的棘轮微通道。这种颗粒浓度的增加是合理的预测，通过一个全面的数值模拟的质量传输沿着与耦合的电荷，热量和流体传输。我们的模型还预测了电流和流体中的流动模式，与实验观察结果吻合得很好。
Insulator-based dielectrophoresis (iDEP) exploits in-channel hurdles and posts etc. to create electric field gradients for various particle manipulations. However, the presence of such insulating structures also amplifies the Joule heating in the fluid around themselves, leading to both temperature gradients and electrothermal flow. These Joule heating effects have been previously demonstrated to weaken the dielectrophoretic focusing and trapping of microscale and nanoscale particles. We find that the electrothermal flow vortices are able to entrain submicron particles for a localized enrichment near the insulating tips of a ratchet microchannel. This increase in particle concentration is reasonably predicted by a full-scale numerical simulation of the mass transport along with the coupled charge, heat and fluid transport. Our model also predicts the electric current and flow pattern in the fluid with a good agreement with the experimental observations.