AN ELECTROSTATICALLY ACTUATED POLYMER MICROVALVE EQUIPPED WITH A MOVABLE MEMBRANE-ELECTRODE

An electrostatically actuated polymer microvalve with a movable membra ne electrode is presented. The microvalve cases are made by thermal in jection molding of conductive polyamide, The movable membrane acting a s an electrode consists of two insulating layers with a conductive lay er in between. The three layers are patterned differently and transfer red from a silicon wafer to the valve case in a batch process. The cas e of the microvalve and the three-layer membrana are joined by adhesiv e injected into cavities in the case. The three-layer membrane is move d electrostatically by a suitable voltage applied between the case and the membrane, The membrane of 3 mu m thickness is attracted to the up per or the lower valve chamber, thus opening or closing the inter of t he microvalve. The microvalve has an outer diameter of 5 mm and is 3 m m thick. The membrane electrode is moved when the voltage applied is a pproximately 60-150 V. Volume flows of up to 0.2 ml s(-1) are attained at a differential pressure of 1100 hPa.