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Published May 1, 2003 | public
Journal Article Open

Thermocapillary actuation of liquid flow on chemically patterned surfaces


We have investigated the thermocapillary flow of a Newtonian liquid on hydrophilic microstripes which are lithographically defined on a hydrophobic surface. The speed of the microstreams is studied as a function of the stripe width w, the applied thermal gradient |dT/dx| and the liquid volume V deposited on a connecting reservoir pad. Numerical solutions of the flow speed as a function of downstream position show excellent agreement with experiment. The only adjustable parameter is the inlet film height, which is controlled by the ratio of the reservoir pressure to the shear stress applied to the liquid stream. In the limiting cases where this ratio is either much smaller or much larger than unity, the rivulet speed shows a power law dependency on w, |dT/dx| and V. In this study we demonstrate that thermocapillary driven flow on chemically patterned surfaces can provide an elegant and tunable method for the transport of ultrasmall liquid volumes in emerging microfluidic technologies.

Additional Information

©2003 American Institute of Physics. (Received 15 August 2002; accepted 30 January 2003; published online 4 April 2003) This work was supported by NSF-CTS-0088774, NSFDMR-9809483, NSF-DMR-0213706 and US Army ARDEC DAAE30-02-C-1141. J.M.D. gratefully acknowledges a NDSEG fellowship.


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