電潤濕動態行為探討

The dynamic behavior of electrowetting

詹正輝(Cheng-Hui Chan)

指導教授 ： 曹恆光

國立中央大學/工學院/化學工程與材料工程學系/碩士(2014年)

摘要

本論文探討影響電潤濕過程中的各種變因和動態行為。由李普曼楊氏方程式可知，電壓一直是影響電潤濕效應的重要因素，影響了最終角度變化量。然而電壓除了影響接觸角的變化量之外，也影響電潤濕效應的反應時間和過程的液滴形狀變化。另外除了電壓，還有一些因素會影響電潤濕效應，像是工作流體濃度、基材表面粗糙度和介電層厚度，這在以往的論文較少被討論。當工作流體濃度越高，相同電壓下電潤濕效應的接觸角變化量亦越大，而且也影響了電潤濕效應的反應時間，然而有一個有趣的情形被觀察到，當濃度增加到一定濃度之上，角度變化量就不會再提高，類似於電潤濕飽和接觸角，我們發現濃度和電壓一樣也會產生此現象。當超過某濃度，改變濃度只會帶來電潤濕效應反應時間的變化。表面粗糙度對電潤濕效應會產生影響，當表面的粗糙度越高，電潤濕效應會越不明顯，接觸角度變化量會越少。介電層厚度也深深影響了電潤濕效應，本文使用兩種介電層，分別是氧化石墨薄膜和不鏽鋼氧化層，當介電層厚度越厚，電潤濕效應也越不明顯，接觸角度變化量亦越少。透過對上述各項因素的探討，能更有效的操控電潤濕現象。

關鍵字

電潤濕 ； 石墨烯 ； 動態行為

並列摘要

The various parameters affect the dynamic behavior of electrowetting discussed in the study. From Lippman-Young's equation, the applied voltage is an important parameter affecting electrowetting. It affects the changes of contact angle. However, the applied voltage affects not only the changes of contact angle, but also the reaction time of electrowetting and the changes of drop shape. Besides the applied voltage, there are other parameters affecting electrowetting such as the concentration of working fluid、the roughness of substrate surface、the thickness of dielectric layer. These parameters were discussed less in previous studies.
When the concentration of working fluid is increased, the changes of contact angle are larger under the same applied voltage, and the reaction time of elctrowetting is shorter. However, as the concentration is above the specific concentration, the changes of contact angle no longer change. The situation is similar to contact angle saturation induced by voltage. As the voltage is above the specific voltage, the changes of contact angle are the same. We call it saturation concentration (about 10 mM). The surface roughness also affects the electrowetting effect. With the increase of roughness, the electrowetting effect is insignificant, so the change of contact angle are smaller. At last, the thickness of dielectric layer strongly affects the electrowetting effects. Two dielectric materials are employed in this study. They are oxidation graphite films and oxidation steel films. The thicker the dielectric layer is, the more insignificant the electrowetting effect is. The changes of contact angle is smaller. Through the control of these parameters, the more effective manipulation is expected.

並列關鍵字

electrowetting ； graphene ； dynamic behavior

參考文獻

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