Low-cost technology for high-density microvalve arrays using polydimethylsiloxane (PDMS)

In this paper, a rapid and low-cost fabrication technology for high-density microvalve arrays is presented. For proof of the concept, a pneumatically-actuated three-way microvalve system composed of three independent one-way valve units was fabricated and tested. Each valve unit has a membrane, which is actuated by external negative air pressure. Intervals between the valve units are smaller than 780 μm. These small intervals have been realized by providing the system with a layer of microchannels to conduct the air pressure to the valve units. All the parts were made of inexpensive silicone elastomer - polydimethylsiloxane (PDMS) - and rapidly fabricated with molding and spin-coating. 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).