Abstract
Novel microfluidic valves based on the solid–solid phase transition of a thermally responsive shape-memory polymer (SMP) have been developed. Both normally open and normally closed valves were constructed and satisfactory performances were obtained, such as an actuation time of 108 ms, a minimum necessary power of 65 mW, and a withstanding pressure of (1.1±0.3)×102 kPa. Only a small energy of 44 mJ was required to release the stored energy for valve actuation. This SMP microfluidic valve fulfills most requirements for the implementation into disposable polymer chips and thus is expected to contribute to the practical use of microfluidic devices.