Reciprocating thermocapillary plug motion in an externally heated capillary
Ang, Yi Zhen
Date of Issue2006
School of Mechanical and Aerospace Engineering
This paper reports the concept and experimental results of reciprocating thermocapillary motion of a liquid plug in microchannels. This paper first describes a one-dimensional analytical model for the transport of microplugs in a capillary. The model considers the coupling effect between heat transfer in the capillary wall and the surface tension driven movement of the plug. Because surface tension depends on temperature, the transient temperature distribution determines the surface tension difference across a plug and thus its movement. In the experiments, we used two heaters, which were activated alternatively. The liquid plug was positioned between the two heaters. The periodic temperature gradients generated by the two heaters made the liquid plug to move back and forth. The position of the plugs was captured and evaluated using a CCD camera. This paper presents the results of this motion with different switching frequencies, viscosities and plug sizes. This actuation concept has potential applications in postprocessing stages for droplet-based microfluidics.
Microfluidics and nanofluidics
© 2006 Springer-Verlag. This is the author created version of a work that has been peer reviewed and accepted for publication by Microfluidics and Nanofluidics, Springer-Verlag. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: DOI: [http:/dx.doi.org/10.1007/s10404-006-0098-3].