Polymer-based in-channel active microvalves have been proposed and fabricated. The valves are operated by pneumatic/thermopneumatic actuation. In this microvalve, polymer monolith, which acts as flow stopper, is formed inside microchannel using photopolymezation technique to achieve possible size miniaturization, batch fabrication, and easy integration.
Two types of microvalves are proposed and fabricated; latch type and normally-open type. The threshold pressures to move the polymer monolith are measured about 77 kPa for latch type and 22 kPa for normally-open type. For both latch type and normally-open type, flow rates linearly increase with the channel pressure in ‘Open State’ and the flow leakage rate in ‘Close State’ is negligible (below 0.04μL/min at 12 kPa).
Thermopneumatic operation of the normally-open type valve is measured. In this case, the actuation chamber is filled with water. The valve closes by applying power on actuation chamber and opens again by turning-off power. The power consumption is about 165 mW at operation voltage of 5 V.
