Pumping Liquids and Particles Using AC Electroosmosis

• Main Authors: Chun-HsienWu, 吳俊賢
• Other Authors: Tzong-Shyng Leu
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/82609581532716818978

碩士 === 國立成功大學 === 航空太空工程學系碩博士班 === 98 === Recently AC Electroosmosis (ACEO) has been applied for fluid transport, mixing and micro/nano particles concentrating. ACEO pumping effects happen when ac signals are applied to arrays of asymmetric interdigitated microelectrodes. Net fluid flow is induced by asymmetric fluid vortices which are caused by asymmetric electrode geometries. Biased Polarization AC Electroosmosis (B-P ACEO) is another type of ACEO. Instead of ac sinusoidal signal, dc-biased ac signals are used in B-P ACEO. Based on the electrodes with positive or negative biasd ac signals, Faradic charge and capacitive charging mechanisms occurs. Net fluid flow is formed by different biased polarizations. This thesis reports that pumping effect by B-P ACEO is more efficient than conventional ACEO with the same electrode geometry. This thesis also studies the difference between symmetric electrode and asymmetric electrode of B-P ACEO by difining surface velocity (Vs) which is particle’s velocity along the surface of electrodes. The dependence of surface velocity (Vs) and frequency is descried for the same signal and fluid with conductivity at 0.00024 S/m. Experiments present that there are characteristic frequency on both B-P ACEO and ACEO. Finally, this paper presents that asymmetric electrode Type II of B-P ACEO has the highest surface velocity (Vs) for all driven signals.