An electrostatically actuated polymer microvalve equipped with a movable membrane electrode

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