icrofluidic doublets in aqueous samples generated by microfabricated hermal probes

This paper describes an investigation of microfluidic actuation of doublet patterns in samples of water on blank substrates, using singular and arrayed microfabricated thermal probes. A doublet is a twodimensional flowpattern consistingof adjacent, opposing vorticeswith linear streamlines between them. In thiswork, each probe consists of a polyimide thin film cantileverwith ametal heater near the tipwhich generates a temperature gradient up to 1 ◦C/ malong its length. The probes are 360 mlong, 42–120 m wide, and 3.5 m thick, and the tips are typically <1mm away from the liquid surface. The velocity of the