A novel microvalve using the electrokinetic motion of electrically induced Janus droplet (EIJD) is presented in this paper. The device is fabricated by injecting an EIJD with the diameter of approximately 80 μm into a microchamber connecting several microchannel branches. The EIJD is developed from an oil droplet covered by Al2O3-nanoparticles under electric field. The microvalve is controllable by electric field. Under an electric field, the Janus droplet undergoes electrokinetic motion in the microchamber, moves to one branch channel and blocks its entrance. By switching the electric field direction, the Janus droplet detaches from this entrance and moves to block another branch channel. In this way, the flow direction in the microvalve changes. In this research, the electrokinetic motion of the EIJD in a circular microchamber under the switching electric field was studied first. The result indicates that the Janus droplet always rotates to get aligned with the electric field. Then, the performance of the microvalve was investigated systematically. The results confirm the capability of such a microvalve in sealing, switching time and flow rate control. Furthermore, by comparing with the case of using a plain oil droplet in such a microvalve, it is proven that the EIJD is essential in realization of a non-leakage microvalve. The EIJD-based microvalve shown in this paper offers great potential in fabricating integrated microfluidic devices.

中文翻译：

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使用电诱导 Janus 液滴的电动运动的微型阀

本文提出了一种利用电诱导 Janus 液滴 (EIJD) 的电动运动的新型微型阀。该装置是通过将直径约为 80 μm 的 EIJD 注入连接几个微通道分支的微室中制造的。EIJD 是由在电场下被 Al2O3 纳米颗粒覆盖的油滴发展而来的。微型阀是由电场控制的。在电场作用下，Janus 液滴在微室中进行电动运动，移动到一个分支通道并阻止其进入。通过改变电场方向，Janus 液滴从这个入口分离并移动以阻塞另一个分支通道。这样，微型阀中的流动方向发生了变化。在这项研究中，首先研究了EIJD在开关电场作用下在圆形微室中的动电运动。结果表明 Janus 液滴总是旋转以与电场对齐。然后，系统地研究了微型阀的性能。结果证实了这种微型阀在密封、切换时间和流量控制方面的能力。此外，通过与在这种微型阀中使用普通油滴的情况进行比较，证明EIJD对于实现无泄漏微型阀是必不可少的。本文中展示的基于 EIJD 的微阀在制造集成微流体装置方面具有巨大的潜力。系统地研究了微型阀的性能。结果证实了这种微型阀在密封、切换时间和流量控制方面的能力。此外，通过与在这种微型阀中使用普通油滴的情况进行比较，证明EIJD对于实现无泄漏微型阀是必不可少的。本文中展示的基于 EIJD 的微阀在制造集成微流体装置方面具有巨大的潜力。系统地研究了微型阀的性能。结果证实了这种微型阀在密封、切换时间和流量控制方面的能力。此外，通过与在这种微型阀中使用普通油滴的情况进行比较，证明EIJD对于实现无泄漏微型阀是必不可少的。本文中展示的基于 EIJD 的微阀在制造集成微流体装置方面具有巨大的潜力。