Electrothermally actuated inline microfluidic valve

A normally open electrothermally actuated inline microvalve that has been developed, fabricated and tested with liquids is presented. These actuators use high volumetric expansion of a sealed patch of Paraffin heated above its melting point, providing large displacements and forces while using low power. The inline valve is surface micromachined on top of preformed flexible microfluidic channels using a low temperature fabrication process; therefore it is suitable for integration with microfluidic networks requiring actuation of a large number of independent valves under electrical control. Complete closure of sealed microchannels has been observed with power as low as 40 mW. Response times of 15 ms have been measured. Breakdown of the inline valve occurs at an upstream pressure of 23 psig. (C) 2003 Elsevier Science B.V. All rights reserved.