本研究為應用電濕潤（Electro-wetting on dielectrics, EWOD）原理驅動晶片上之微液滴，透過改變甘油與水的比例，研究在不同的黏滯力、表面張力、致動力下，對液滴動態行為、響應時間所造成的影響。主要實驗設計為利用共平面式（Coplanar）對稱（Symmetric）之電極設計以及微機電製程加工技術來驅動微液滴於電極表面上做特定方向的驅動。
影響液滴於電極表面動態行為因素包含：電壓、表面張力、黏滯力等，經本研究的實驗結果顯示液滴響應時間和黏滯力呈正相關。同一濃度甘油水溶液，在三種電壓大小驅動下，160 V驅動達安定時間最短，80 V居中，120 V最長，此現象與電濕潤致動力、液滴表面張力及黏滯力三者之合力有關。電濕潤現象為二階非線性系統，由中低電壓120V、80V驅動為二階過阻尼系統；高電壓160 V驅動則呈二階欠阻尼系統。經因次分析，得到一個能夠預測液滴動態行為的無因次液體性質參數 ，當 值高於3.6878時，具有表面波動的情形，當 值為14.9742時，整個系統具有最短的穩定時間0.2s。並利用線性回歸將實驗數據擬合出一個預測模型。

In this study, electro-wetting on dielectrics (EWOD) is applied to drive a droplet on coplanar electrodes. Coplanar electrodes patterned on the substrate allow a true sessile condition with no wire into the droplet. This study investigate the effects of viscosity and surface tension on spreading dynamics, including response time and spreading behaviors in response to various DC voltages, based on experiment. MEMS microfabrication with coplanar symmetric electrode design is used for fabricating the EWOD devices in this study. When a voltage is applied, the EWOD device generates symmetric electro-wetting force. The droplet is driven in a specific direction.
The main factor that affects droplet dynamic motion is the applied voltage, surface tension and viscosity. It is experimentally found that settling time of contact line (i.e., time to reach equilibrium radius) are proportional to viscosity. It is also found that settling time is dependent on the force balance between the driving electrical force, surface tension force and viscous force. The spreading behaviors of a droplet can be simplified into a model of the second-order nonlinear dynamic system. One of the main factor that affects droplet dynamic motion is the droplet sustained oscillating behavior in the height. To the best of our knowledge, this is the first detailed study of viscosity and surface wave of the spreading behaviors over a broad range of viscosities (0.9−1011 mPa·s) under various step responses.
In this study, the contact line and height dynamic behaviors of a droplet on a plane are analyzed. This study proves that the applied voltage, viscosity, surface tension of a droplet is significantly affect the droplet dynamic behaviors.

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