悬空零电极介电湿润芯片的设计

Design of EWOD device with suspended ground electrode

针对目前单极板数字微流控芯片驱动液滴的效果多通过数值仿真方法验证而缺乏实验支持,本文提出将单极板结构中的零电极进行悬空设计,并通过实验对比分析了设计的悬空零电极单极板结构的芯片和传统双极板结构的芯片对液滴的驱动效果。首先,基于介电湿润原理,推导出传统双极板结构中液滴所受到的介电驱动力以及每个阻力,接着,对文中设计的悬空零电极结构的单极板数字微流控芯片中液滴的受力情况进行分析。然后,对比分析两种结构的数字微流控芯片中液滴的受力情况。最后,对两种结构的数字微流控芯片驱动去离子水微液滴的效果进行试验验证。实验结果显示:驱动同等体积大小的微液滴时,本文设计制作的悬空零电极单极板芯片比双极板结构的芯片所需的电压更低,液滴的运动速度更快;当有效驱动电压达到44V时,液滴的速度可以达到15cm/s。得到的实验结果证明了在单极板悬空零电极结构的数字微流控芯片上液滴驱动速度更高,驱动电压更低。

This paper researches how to design the suspended ground electrode of an electrowetting-on-dielectric（EWOD）based device, because most of the existing investigations for the efficiency of single-plate EWOD device were carried out by means of numerical simulations and lack of experimental results. Then, it coam- pares,the driving effectiveness for a liquid droplet by the proposed EWOD device with suspended ground elec- trode and a traditional bipolar plate device. Based upon the theory of the EWOD, the dielectric, deriving EWOD force and each resistive force of the droplet holding between the bipolar plates were derived, and the forces of the droplet sitting on the single-plate EWOD device were analyzed. Then,the forces were compared between the bipolar plate device and the single-plate EWOD device. Finally, the driving characteristics of the droplet were tested via the fabricated EWOD device. The experimental results show that the driving voltage of single-plate is more low, and its velocity is more faster than that of the bipolar plates; the velocity of 1 ptL droplet can be 15 cm/s when the driving potential is 44 VRMS. In conclusion, the obtained experimental results validate the feasibility of the single-plate EWOD device with suspended ground electrode for its faster velocity and low driving potential.