AN ELECTROCHEMICAL ACTIVE VALVE

A novel electrochemical microactuator was developed, which operates as an active valve. The microactuator consists of an electrochemical cel l and a membrane that deflects because of the pressure of oxygen gas g enerated by electrolysis. Relatively large pressures (up to tens of ba rs) can be reached with only low energy consumption (in the mu W range ). In a first prototype a Cu/aq. 1M CuSO4/Pt system was used in an ele ctrochemical cell with dimensions 2x 2 x 1 mm(3), fabricated with sili con micromachining and thin film deposition techniques. When the actua tor was driven at 1.6 V and currents below 50 mu A, pressures of 2 bar could be obtained within seconds, causing membrane deflections in the 30 to 70 mu m range. It was found that, in order to improve the perfo rmance of the microactuator, it will be necessary to replace the Cu/Cu 2+ electrode. A possible alternative is the Sb/Sb-oxide electrode. Thi s system was studied by cyclic voltammetry and the first results are p romising. (C) 1997 Published by Elsevier Science Ltd.