POLYMERIC STACK-ASSEMBLED MICROPUMP WITH SU-8 CHECK VALVES

Abstract

This paper presents a new concept of designing and fabricating polymeric micropumps. The micropump is made of SU-8 photoresist and polymethylmethacrylate (PMMA). The key elements of the micropump are the micro check valves, which are fabricated in a 100-μm-thick SU-8 film. The SU-8 part is designed as a disc with 10-mm diameter. The check valves are 1-mm discs suspended on a compliant orthoplanar spring with 4 arms. The cross section of the spring beam has a dimension of 100 μm × 100 μm. The pump is designed as a stack of different layers, which are made of PMMA and SU-8. The low spring constant of the SU-8 check valves allows the use of relatively low drive voltages on the order of several 10 volts for the piezodisc, which works as the pump's actuator. Pump rates up to 1 ml/min and back pressures up to 200 mm water have been achieved. The pump design shows the feasibility of our current effort to make microfluidic systems based on the lamination of different polymeric materials.