實驗探討水滴電潤濕反應現象

Experimental Investigation of the Electrowetting Effect for A Water Droplet

吳定恭(Ting-Kung Wu)

國立虎尾科技大學/工程學院/機械與機電工程研究所/碩士(2007年)

摘要

液滴在介電層上施加適當電壓，因電荷的累積在固液介面將改變其潤濕性，該特性常被應用於生醫及透鏡製作科技領域，而介電層的性質對液滴在電潤濕效應有極大的影響，本論文將改變三種介電層材料（如TiN、NbN及Ultra 123），以開放式電潤濕實驗配置探討水滴在各種不同介電層上得反應現象，並將結論應用於水滴的傳輸運動。
研究結果發現當外加電壓跨過適當電壓值時，三種介電層材料均呈現典型的水滴接觸角反應曲線，該曲線可歸納為電潤濕反應區、穩態區及恢復區；反應區顯示當外加電壓誇過一門檻電壓時，水滴在極短時間內產生電潤濕效應，電壓持續作用時接觸角不再改變係為穩態區；電壓移除時液滴會快速恢復，三種介電層材料呈現的電潤濕反應電壓值以TiN最低僅需40V。研究結果發現，當水滴因電潤濕產生左右接觸角不對稱時，水滴會受到淨作用力牽引，產生傳輸運動，接觸角差異愈大運動愈明顯。

並列摘要

The electrowetting (EW) effect, that the wettability is hydrophilic on the surface between solid and liquid since an electric field is applied to lead to the charge accumulation, for a water droplet has been presented in the thesis. Using openly electrowetting setup to investigate the EW effect of the dielectric constant, three kinds of material were variable, including TiN, NbN, and Ultra 123. From results, an inductive curve of the contact angle versus the applied voltage is generally for these experiment dielectric layers as the applied voltage is over the threshold, which results in the hydrophilic phenomenon. The curve can be concluded into the electrowetting action zone, the stable hydrophilic zone, and the reinstating zone. From the curve, the electrowetting and reinstating time all demonstrates less than 0.25 seconds. Apart from, the threshold voltage of the TiN is lowest, around 40V, among the experimental dielectric materials.

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