Development of a Latchable Microvalve Employing a Low-Melting-Temperature Metal Alloy

We present the design, fabrication, and characterization of a latchable microvalve. The valve can be held in the ON- or OFF-state without consuming power. A low-melting-temperature metal alloy provides structural support to hold the valve in place when latched. The metal alloy piece liquefies when it is heated above 62 degrees C, allowing a pneumatic actuator to change the valve state. When the metal cools and solidifies, the valve is once again latched. This type of valve may be useful for portable lab-on-a-chip devices that require low-power operation and long-term fluid storage. A thin-film metal heater has been integrated into the polydimethylsiloxane device to provide localized heating for individual valve elements. Valve closing and opening response times have been simulated and verified by experiment. The burst pressure has been experimentally characterized and parameters influencing this burst pressure have been modeled.