Exploration and evaluation of embedded shape memory alloy (SMA) microvalves for high aspect ratio microchannels

This paper presents a microvalve actuated by shape memory alloy (SMA). This microvalve is designed particularly for controlling high aspect ratio polydimethylsiloxane (PDMS) channels and can be embedded into PDMS based microfluidic chips. This SMA microvalve can be designed either as a normally closed or normally open microvalve. Both designs utilize SMA wires for thermal actuation and operation to open or close microchannel flow. In this work, detailed parametric studies have been performed. The response open time of the normally open microvalve could be as low as 1 s at a flow rate of 4 μL/min, which is very short for a thermomicrovalve.