Jang Ling-Sheng, Lin Guo-Hua, Lin Yi-Liang, Hsu Chih-Yuan, Kan Wai-Hong, Chen Chiun-Hsun
Department of Electrical Engineering and Center for Micro/Nano Science and Technology, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan.
Biomed Microdevices. 2007 Dec;9(6):777-86. doi: 10.1007/s10544-007-9089-8.
Electrowetting on dielectric (EWOD) moving fluid by surface tension effects offers some advantages, including simplicity of fabrication, control of minute volumes, rapid mixing, low cost and others. This work presents a numerical model using a commercial software, CFD-ACE+, and an EWOD system including a microfluidic device, a microprocessor, electric circuits, a LCD module, a keypad, a power supply and a power amplifier. The EWOD model based on a reduced form of the mass conservation and momentum equations is adopted to simulate the fluid dynamics of the droplets. The EWOD device consists of the 2 x 2 mm bottom electrodes (Au/Cr), a dielectric layer of 3,000 A nitride, 500 A Teflon and a piece of indium tin oxide (ITO)-coated glass as the top electrode. The complete EWOD phenomenon is elucidated by comparing simulation with the experimental data on droplet transportation, cutting and creation. In transportation testing, the speed of the droplet is 6 mm/s at 40 V(dc). In addition, the droplet division process takes 0.12 s at 60 V(dc) in the current case. Finally, a 347 nl droplet is successfully created from an on-chip reservoir at 60 V(dc).
基于表面张力效应的介电电泳（EWOD）移动流体具有一些优势，包括制造简单、微体积控制、快速混合、低成本等。本文介绍了一种使用商业软件CFD-ACE+的数值模型，以及一个EWOD系统，该系统包括微流体装置、微处理器、电路、LCD模块、键盘、电源和功率放大器。采用基于质量守恒和动量方程简化形式的EWOD模型来模拟液滴的流体动力学。EWOD装置由2×2毫米的底部电极（金/铬）、3000埃的氮化物介电层、500埃的聚四氟乙烯以及一块涂有氧化铟锡（ITO）的玻璃作为顶部电极组成。通过将模拟结果与液滴运输、切割和生成的实验数据进行比较，阐明了完整的EWOD现象。在运输测试中，在40伏（直流）电压下液滴速度为6毫米/秒。此外，在当前情况下，在60伏（直流）电压下液滴分裂过程需要0.12秒。最后，在60伏（直流）电压下成功从片上储液器中生成了一个347纳升的液滴。
