Combination of ac electroosmosis and dielectrophoresis for particle manipulation on electrically-induced microscale wave structures
Combination of ac electroosmosis and dielectrophoresis for particle manipulation on electrically-induced microscale wave structures
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DOI：
10.1088/0960-1317/25/3/035003
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发表时间：
2015-03-01
影响因子：
2.3
通讯作者：
Chang, Hsien-Chang
中科院分区：
文献类型：
--
作者：
Chung, Cheng-Che;Glawdel, Tomasz;Chang, Hsien-Chang
提出了一种利用电辅助光刻技术在规则的叉指电极阵列上制作可控微尺度波结构的简单方法。使用传统的多层光刻技术制造平滑波结构是极其困难的，如果不是不可能的话。制作的波结构仔细测量使用光学轮廓仪和测量的波轮廓中使用的电场的数值模拟和评估的参数影响制作的波结构。结果表明，结合光滑波结构和IDE阵列提供了独特的能力，包括颗粒的浓度，聚集和分离的颗粒操纵。通过组合的波结构和IDE阵列操纵的粒子运动取决于所施加的频率由交流电渗（ACEO）、介电泳（DEP）或两者的组合来控制。在较低频率（类似于30 kHz）下，ACEO占主导地位，并且颗粒被驱动沿波结构的谷沿着移动;而在较高频率（类似于200 kHz）下，DEP力占主导地位，其将颗粒集中在波结构的峰处。此外，改变交流波形从正弦波到方波允许粒子运动的动态控制。大小相关的颗粒分离的波结构也证明了0.5 μ m和2 μ m的颗粒，分离成两个群体的阻力和DEP力的联合作用时，被泵送通过ACEO流的混合物。
This work presents a simple method to fabricate controllable microscale wave structures on the top of regular interdigitated electrode (IDE) arrays using electrically-assisted lithography techniques. Smooth wave structures are extremely difficult, if not impossible, to fabricate using traditional multilayer photolithography technology. The fabricated wave structures were carefully measured using an optical profiler and the measured wave profiles were used in the numerical simulation of electrical field and for evaluating the parameters influencing the fabricated wave structure. It is demonstrated that the combined smooth wave structure and IDE array offer unique capability for particle manipulation including particle concentration, aggregation and separation. Particle motion manipulated via the combined wave structure and IDE array is governed by ac electroosmosis (ACEO), dielectrophoresis (DEP) or a combination of both depending on the applied frequency. At lower frequencies (similar to 30 kHz), ACEO dominates and particles are driven to move along the valleys of the wave structures; while at higher frequencies (similar to 200 kHz), DEP force dominates which concentrates particles at the peaks of the wave structures. In addition, varying the ac waveform from sine-wave to square-wave allows for dynamic control of particle motion. Size-dependent particle separation over the wave structure is also demonstrated for a mixture of 0.5 mu m and 2 mu m particles that are separated into two populations by the joint effects of drag and DEP forces when being pumped to flow via ACEO.