- 學位論文
介電液滴在交流電場下界面動態行為之探討
Dynamic Interfacial Behavior of A Dielectric Liquid Drop in AC Electric Field
若您是本文的作者，可授權文章由華藝線上圖書館中協助推廣。
摘要
本論文探討在基板上介電液滴，液滴為矽油，環境液體為混合醇水溶液，兩液體皆為低黏度，利用同心圓電極基板和外加交流電訊號，使液滴、環境液體和基板接觸線附近產生時變作用力，進而使液滴來回振動並在液液界面上產生波動行為。在其他實驗參數固定下，調變輸入交流電訊號頻率。實驗結果顯示，交流電訊號頻率和液液界面波動行為密切相關，輸入頻率在一範圍內，液液界面會產生節點(Node)與反節點(Antinode)，一固定節點與反節點數目代表一個振動膜態(Oscillation mode)，在同一振動膜態下，不同輸入頻率，會改變節點位置且隨著輸入頻率越高，節點與反節點的數目越多，則進入下一個振動膜態，在輸入電訊號頻率5~90 Hz，可陸續激發出二、四與六個節點。取液滴高度作為振幅對頻率作分析，發現並無明顯局部極大值，意即尚未激發出此液滴系統之共振模態抑或在實驗頻率下共振模態不存在於此系統中，導致此結果原因推測有二，其一為環境液體造成系統阻尼比過大，二為同心圓電極設計使液滴受非軸對稱作用力，抑制軸對稱振動波形之產生。
並列摘要
This research focus on a sessile dielectric drop immersed in an another dielectric liquid. The sessile drop and environment liquid are silicone oil and alcohol-mixture separately. By input ac electrical signal to patterned concentric electrode under the sessile drop, the drop oscillated periodically due to induced time-varying electric force concentrated on the vicinity of contact line. And the drop oscillation wave pattern on liquid interface was generated. The experimental results showed that the interface pattern highly depends on input signal frequency. And the nodes and antinodes appeared on the interface simultaneously during the drop oscillation. The fixed number of nodes and antinodes indicated that the same oscillation mode was be excited. As input frequency increased from 5 to 90 Hz, 2, 4 and 6 nodes were excited continually. In addition, resonance was not observed in our dielectric liquid system. The large damping ratio and axisymmetric electric field might result in it.
參考文獻
[1] B. Berge and J. Peseux, "Variable focal lens controlled by an external voltage: An application of electrowetting," European Physical Journal E, vol. 3, 2000.
[2] S. Kuiper and B. H. W. Hendriks, "Variable-focus liquid lens for miniature cameras," Applied Physics Letters, vol. 85, 2004.
[5] R. A. Hayes and B. J. Feenstra, "Video-speed electronic paper based on electrowetting," Nature, vol. 425, 2003.
[7] F. Mugele, "Fundamental challenges in electrowetting: from equilibrium shapes to contact angle saturation and drop dynamics," Soft Matter, vol. 5, 2009.
[10] K. S. Yun, I. J. Cho, J. U. Bu, G. H. Kim, Y. S. Jeon, C. J. Kim, and E. Yoon, "A micropump driven by continuous electrowetting actuation for low voltage and low power operations," 14th IEEE International Conference on Micro Electro Mechanical Systems, Technical Digest, 610, 2001.