Insulator‐based dielectrophoresis (iDEP) exploits the electric field gradients formed around insulating structures to manipulate particles for diverse microfluidic applications. Compared to the traditional electrode‐based dielectrophoresis, iDEP microdevices have the advantages of easy fabrication, free of water electrolysis, and robust structure, etc. However, the presence of in‐channel insulators may cause thermal effects because of the locally amplified Joule heating of the fluid. The resulting electrothermal flow circulations are exploited in this work to trap and concentrate nanoscale particles (of 100 nm diameter and less) in a ratchet‐based iDEP microdevice. Such Joule heating‐enabled electrothermal enrichment of nanoparticles are found to grow with the increase of alternating current or direct current electric field. It also becomes more effective for larger particles and in a microchannel with symmetric ratchets. Moreover, a depth‐averaged numerical model is developed to understand and simulate the various parametric effects, which is found to predict the experimental observations with a good agreement.

中文翻译：

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基于绝缘体的介电泳微器件中纳米粒子的焦耳加热电热富集

基于绝缘体的介电泳 (iDEP) 利用绝缘结构周围形成的电场梯度来操纵粒子以用于各种微流体应用。与传统的基于电极的介电泳相比，iDEP 微器件具有易于制造、无需电解水、结构坚固等优点。然而，通道内绝缘体的存在可能会由于局部放大的焦耳热而引起热效应。流体。在这项工作中，利用由此产生的电热流循环在基于棘轮的 iDEP 微型器件中捕获和浓缩纳米级颗粒（直径为 100 nm 或更小）。发现这种纳米粒子的焦耳加热使电热富集随着交流或直流电场的增加而增长。对于较大的颗粒和具有对称棘轮的微通道，它也变得更有效。此外，开发了深度平均数值模型来理解和模拟各种参数效应，发现该模型可以很好地预测实验观察结果。