Electro-osmotic pumping on application of phase-shifted signals to interdigitated electrodes

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• 作者：Brian P. Cahill ; Laura J. Heyderman ; Jens Gobrecht and Andreas Stemmer
• 刊名：Sensors and Actuators B: Chemical
• 出版年：2005
• 出版时间：2005
• 年：2005
• 卷：110
• 期：1
• 页码：157-163
• 全文大小：165 K

文摘

Alternating-current (ac) electro-osmotic flow can be implemented in microfluidic pumping systems with the advantage over conventional electro-osmosis that it requires low applied potentials that can be supplied by normal batteries so that it is highly suitable for use in portable lab-on-a-chip systems. We report how the combination of applying phase shifted signals to the interdigitated electrodes and the use of a ground layer causes ac electro-osmotic flow of aqueous electrolytes. The direction of pumping may be changed by varying the phase difference. Velocities up to 100  m/s were observed for applied potentials of less than 1 V_rms. The maximum velocity was observed at phase differences of around ±90°. How surface conductivity affects ac electro-osmosis can be inferred from the effect of varying electrolyte concentration on the frequency of peak velocity.