無動件式高流率電滲泵的製作與特性分析

Fabrication and Performance Study of High Flow Rate Electroosmotic Pump

賴俊伯(Chun-po Lai)

指導教授 ： 吳俊諆

國立中央大學/工學院/機械工程學系/碩士(2007年)

摘要

本文以燒結矽多孔介質製作一高流率的小型電滲泵(electroosmotic pump, EOP)，以燒結矽濾材的多孔介質作為微流道傳輸液體，濾材直徑有二種(D=4, 2.5 cm)，流道孔隙直徑約1-2 μm。此種無動件泵以電雙層(electrical double layer)效應驅動流體，可產生高壓和高流率。我們使用不同濃度(0.5-4 mM)、不同酸鹼值(pH 7.6-9.2) 的硼酸鹽水溶液為工作流體並以不同電壓(25-250 V)進行性能測試。濃度與pH值越高的工作流體能產生的流率越高。電滲泵(D=4 cm)於工作電壓250 V，可產生最大流率Qmax=32 ml/min、最大壓力差Pmax=128 kPa、每單位面積電壓產生的流率Qmax/(AV)=0.012 ml/min/(V.cm2)。
因電解反應隨著電壓增加而增強，在電極附近有氫、氧氣泡產生。藉由加入離子交換膜(Nafion)與透析膜能降低氣泡對流體傳輸的不利影響，此外使用不銹鋼電極取代負極的白金電極也能有效的壓抑氣泡，最大流率可提升15%。以並聯2片濾材(D=2.5 cm)的方式設計製作電滲泵，流率可增加2倍。縮短二電極距離增加電場強度可提升流率，於工作電壓200 V量測泵的性能如下：Qmax=18.6 ml/min、Pmax=210 kPa和Qmax/(AV)=0.023 ml/min/(V.cm2)。此電滲泵能持續不間斷的運作10小時，顯示其有相當的可靠度。

關鍵字

電滲泵 ； 燒結矽多孔介質

並列摘要

A high flowrate electroosmotic (EO) pump is fabricated from a porous sintered silica frit (two sizes with diameter D=4, 2.5 cm) as tortous microchannels (pore diameter about 1-2 μm) to transport liquid. This EO pump has no moving part, which utilizes the electric double layer (EDL) effect as driving force, can generate high back pressure and large flow rate. The working fluid is the borate solution with various range of concentrations (C=0.5-4 mM) and pH value (7.6-9.2). Moderate range of voltages (V=25-250 V) is applied to the electrode. The solution with high concentration and pH vlaue result in high flowrate. The EO pump (D=4 cm) generates maximum flowrate Qmax=32 ml/min, maximum pressure Pmax=128 kPa, and a maximum flow rate per area and per voltage Qmax/(AV)=0.012 ml/min/(V.cm2) at 250 V applied voltage.
Due to the electrolysis reaction in the solution, bubbles (hydrogen and oxigen) generate near the electrode as the applied voltage increase, and that may retard the flow transport. Several approaches are utilized to reduce bubbles flow into downstream of EO pump, including insert the Nafion and dialysis membrane in the cathode chamber and replace the Pt electrode with the stainless steel elctrode. Overall, the flowrate is increased about 15%. Next, the EO pump with smaller porous frit (D=2.5 cm) is tested. The flowrate of EO pump increase twofold by connect two units of frit in parallel. By decreasing the distance of electrode-pair the electrical field strength increase, and the pump performance enhance too, with Qmax=18.6 ml/min, Pmax=210 kPa, and Qmax/(AV)=0.023 ml/min/(V.cm2). This EO pump can continuously run for 10 hours, which show its reliability.

並列關鍵字

porous sintered silica frit ； electroosmotic pump

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