交流电渗粒子收集的研究

Research on the microparticles collection caused by AC electroosmosis

针对低浓度微纳粒子快速准确收集这一MEMS领域瓶颈问题展开了相关研究.实验研究发现,在对称电极芯片上施加低压低频交流电信号,样品中的微纳粒子收集到电极表面固定区域.以交流电场机制为基础,建立了交流电渗对称电极的二维模型及等效电路,推导了交流电渗作用下的微流体流动速度公式,对比研究了介电泳、重力以及浮力作用下微纳粒子的运动速度.通过数值仿真计算,分析了交流电渗作用下微纳粒子在对称电极上的收集位置,研究了介电泳力对于微纳粒子收集的影响,并对仿真与实验进行了对比分析.研究表明,在交流电场机制中低压低频条件下,交流电渗起主导作用,能够快速准确地进行微纳粒子收集.

The low concentration of microparticles collected in micro-electromechanical systems （MEMS） was studied. It was found in experiments that when applying low voltages and low frequencies on symmetrical electrodes, microparticles could be collected in a fixed area. Based on AC electric field, the authors established a 2D model of the symmetrical electrodes and a homotactic circuit, deduced the microfluidic velocity expression, and analyzed mi- croparticle velocities based on their dielectrophoresis, buoyancy and gravity. By means of a numerical simulation, the collection position of the microparticles and the influence of dielectrophoresis were analyzed and the simulation was compared with the experiment. The study showed that AC electroosmosis is the dominant force when low volta- ges and frequencies are applied.