School of Mechatronics Engineering, Harbin Institute of Technology, West Da-zhi Street 92, Harbin, Heilongjiang, PR China 150001.
Lab Chip. 2015 May 21;15(10):2181-91. doi: 10.1039/c5lc00058k.
Position-controllable trapping of particles on the surface of a bipolar metal strip by induced-charge electroosmotic (ICEO) flow is presented herein. We demonstrate a nonlinear ICEO slip profile on the electrode surface accounting for stable particle trapping behaviors above the double-layer relaxation frequency, while no trapping occurs in the DC limit as a result of a strong upward fluidic drag induced by a linear ICEO slip profile. By extending an AC-flow field effect transistor from the DC limit to the AC field, we reveal that fixed-potential ICEO exceeding RC charging frequency can adjust the particle trapping position flexibly by generating controllable symmetry breaking in a vortex flow pattern. Our results open up new opportunities to manipulate microscopic objects in modern microfluidic systems by using ICEO.
本文提出了一种通过感应电荷电渗流（ICEO）实现双极金属条表面上的颗粒位置可控捕获的方法。我们展示了电极表面上的非线性 ICEO 滑移分布，这可以解释在双层弛豫频率以上稳定的颗粒捕获行为，而在直流极限下由于线性 ICEO 滑移分布引起的强烈向上的流体阻力，没有发生捕获。通过将交流流场效应晶体管从直流极限扩展到交流场，我们揭示了固定电位的 ICEO 超过 RC 充电频率，可以通过在涡旋流模式中产生可控的对称破缺，灵活地调节颗粒的捕获位置。我们的研究结果为通过 ICEO 来控制现代微流控系统中的微观物体提供了新的机会。
