Capillarity in lithographically patterned micro channels

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Javed, H., 2013. Capillarity in lithographically patterned micro channels. PhD, Nottingham Trent University.

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Abstract

The spontaneous capillary-driven filling of micro channels is important for a wide range of applications. Reporting for the first time for vertically mounted open top channels, in this work the theory for capillary rise in channels of rectangular cross-section has been tested and verified, taking into account the effects of surface topography assuming a Wenzel state. The theory has been tested via capillary rise experiments using polydimethylsiloxane oils of viscosity 96.0, 48.0, 19.2 and 4.8 mPa s within the 400μm and 600μm closed square glass tubes and SU8 open top smooth walled rectangular cross-section channels having width 400μm and 600μm and depth 135μm. It has been shown that capillary rise heights in plane open top walled channels (with roughness factor of 1) can be fitted using the exact numerical solution and that these are similar to fits using the analytical visco-gravitational solution. The viscous friction contribution was found to be higher than predicted by theory assuming a non-rigidified liquid–air boundary, but far below that for a rigidified boundary, which is recently reported for imbibition into horizontally mounted open micro channels. It has also been observed that fingers of liquid spreading along the internal edges of the smooth walled channels in advance of the main body of liquid consistent with wetting expectations. These fingers were observed to be thicker and larger in size for wider and shallower channels.

Item Type:	Thesis
Creators:	Javed, H.
Date:	2013
Rights:	This work is the intellectual property of the author, and may also be owned by the research sponsor(s) and/or Nottingham Trent University .It may be copied up to 5% of this work for private study, or personal, non-commercial research. Any re-use of the information contained within this document should be fully referenced, quoting the author, title, university, degree level and pagination. Queries or requests for any other use, or if a more substantial copy is required, should be directed in the owner(s) of the Intellectual Property Rights.
Divisions:	Schools > School of Science and Technology
Record created by:	EPrints Services
Date Added:	09 Oct 2015 09:33
Last Modified:	09 Oct 2015 09:33
URI:	https://irep.ntu.ac.uk/id/eprint/30