A novel multi-channel silicon-based piezoelectric micropump with active piezoelectric valve array

Abstract

In order to only use one piezoelectric micropump to simultaneously drive and control multi-channel flow fluids of complex microfluidic systems in biological, chemical and medical applications, and then improve the integration and reduce the size of systems, principle and structure of a multi-channel silicon-based piezoelectric micropump with active piezoelectric valve array are proposed and realized. The micropump is composed of one pumping unit and four active piezoelectric valves with annular boundaries, which form active piezoelectric valve array by uniformly distributing around pumping unit. All valves are connected to pumping unit by corresponding fluid channels and they can realize bidirectional fluid flowing. Therefore, pump can suck fluid from any one or more valves through pumping unit and can discharge fluid to the other one or more valves, which form its six working modes. Silicon-based pump body is processed by photoetching and the micropump is fabricated by fixing circular piezoelectric unimorph actuators on the silicon-based pump body. Flow rate model is established, the flow characteristics under each working mode are experimentally tested. Results show that the micropump can realize simultaneously multi-channel fluid input and output, when it works under three-in and single-out, it has the maximum flow rate and output pressure; the flow rate model can predict its flow rate, the maximum relative error between experimental test result and numerical simulation result is 9.99%; the micropump has high flow control accuracy, when amplitude of driving voltage varies from 35 V to 36 V with step of 0.1 V, it has the minimum change of flow rate of 1 μL min−1, the maximum flow rate deviation of 5 μL min−1 and the maximum relative standard deviation of flow rate control of 0.175%. Therefore, the micropump provide feasible scheme for piezoelectric micropumps to be applied in complex microfluidic systems with multi-channel flow fluids, such as lab-on-chip.