【摘 要】
：
Microchannel plates (MCP),2.1 cm in diameter,0.40 mm thick,and with 3 million uniform holes 7 microns in diameter,have been used for pumping ethanol,2-propanol,methanol,acetone and water.Pumping start
【机 构】
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College of Bioscience and Biotechnology and the Hunan Provincial Key Laboratory of Phytohormones and
【出 处】
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第八届全国微全分析系统学术会议、第三届全国微纳尺度生物分离分析学术会议暨第五届国际微化学与微系统学术会议
论文部分内容阅读
Microchannel plates (MCP),2.1 cm in diameter,0.40 mm thick,and with 3 million uniform holes 7 microns in diameter,have been used for pumping ethanol,2-propanol,methanol,acetone and water.Pumping started at dc voltages as low as 6 V,and a pumping rate of 15-18 ml/min was achieved at 200-250 V for ethanol.The pumping rate was found to be directly proportional to the voltage drop,△V,applied across the channel plate at voltages ≥ 100 V,in agreement with the conventional electro-osmotic equation.Highly reproducible results were given by several MCPs continuously working in ethanol for over one week.Enhancing pumping was realized by stacking of several MCPs in various configurations.In addition to the surface charge induced by surface dissociation and specific adsorption,an additional space charge governed by the field effect in the n-type MCP semiconductor device was found to play an important role in the electro-osmotic pumping.This new mechanism also explains well for the intriguing phenomena described in a recent publication[1] that MCP shows a unique characteristic of directional preference in pumping with net flow consistently induced toward the nearest electrode regardless of polarity of the voltage potential applied.Other electrohydrodynamic (EHD) mechanisms involved in preconditioning of the plates are also discussed.The devices have potential application in voltage controlled micropumps.
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