Abstract
The capillary filling speed of wetting liquids of varying viscosity and surface tension in hydrophilic
nanochannels with an elastic capping layer has been analyzed. The channels, with a height just below 80
nm, are suspended by a thin flexible membrane that easily deforms due to the negative pressure which
develops behind the moving meniscus. In the elastocapillary filling of the channels, two opposite effects compete: the decreased cross channel sections increase the flow resistance, while the Laplace pressure
that acts as the driving force becomes more negative due to the increased meniscus curvature. Although
the meniscus position shows a square root of time behavior as described by the Washburn relation, the
net result of the induced bending of the membranes is a definite increase of the filling speed. We
propose a relatively straightforward model for this elastocapillary process and present experimental
results of the filling speed of ethanol, water, cyclohexane and acetone that are found to be in good
agreement with the presented model, for membrane deflections of up to 80 percent of the original
channel height.
Original language | Undefined |
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Article number | 10.1063/1.2732539 |
Pages (from-to) | 094310 |
Number of pages | 7 |
Journal | Journal of Applied Physics |
Volume | 103 |
Issue number | WP07-01/2 |
DOIs | |
Publication status | Published - May 2007 |
Keywords
- EWI-9789
- IR-67096
- METIS-241620