A pneumatically-actuated three-way microvalve fabricated with polydimethylsiloxane using the membrane transfer technique

In this paper, a three-way microvalve system composed of three independent one-way valve units is presented. Each valve unit has a membrane, which is actuated by external negative air pressure. Intervals between the valve units are smaller than 780 μm, which opens up the possibility of realizing a high-density microvalve array. The small intervals were realized by providing the system with a layer of microchannels to conduct the air pressure to the valve units. In spite of the extra layer of microchannels, the device has been fabricated through a simple process by adopting polydimethylsiloxane (PDMS) as the material for the microchannel chips as well as the membrane. In particular, a newly developed technique for wafer level transfer of a PDMS membrane has been proven to be effective. Flow characteristics of the microvalve system for water are presented. The microvalve works in an on–off manner with hysteresis. No leakage has been observed in the closed state. In the open state, measured flow resistances (pressure drops) are within the range of 1.65–2.29 kPa (μl min−1)−1, and consistent with an electric circuit model.