Evaporation-induced cavitation in nanofluidic channels

Cavitation, known as the formation of vapor bubbles when liquids are under tension, is of great interest both in condensed matter science as well as in diverse applications such as botany, hydraulic engineering, and medicine. Although widely studied in bulk and microscale-confined liquids, cavitatio...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2012-03, Vol.109 (10), p.3688-3693
Main Authors: Duan, Chuanhua, Karnik, Rohit, Lu, Ming-Chang, Majumdar, Arun
Format: Article
Language:English
Subjects:
Bubbles
Cavitation flow
Condensed matter physics
Diffusion
Equipment Design
Evaporation
Evaporation rate
Liquids
Menisci
Microfluidic Analytical Techniques
Microfluidics - methods
Models, Statistical
Nanotechnology - methods
Physical Sciences
Porosity
Pressure
Surface Tension
Temperature
Vapors
Water - chemistry
Water channels
Water pressure
Xylem
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Summary:Cavitation, known as the formation of vapor bubbles when liquids are under tension, is of great interest both in condensed matter science as well as in diverse applications such as botany, hydraulic engineering, and medicine. Although widely studied in bulk and microscale-confined liquids, cavitation in the nanoscale is generally believed to be energetically unfavorable and has never been experimentally demonstrated. Here we report evaporation-induced cavitation in water-filled hydrophilic nanochannels under enormous negative pressures up to –7 MPa. As opposed to receding menisci observed in microchannel evaporation, the menisci in nanochannels are pinned at the entrance while vapor bubbles form and expand inside. Evaporation in the channels is found to be aided by advective liquid transport, which leads to an evaporation rate that is an order of magnitude higher than that governed by Fickian vapor diffusion in macro-and microscale evaporation. The vapor bubbles also exhibit unusual motion as well as translational stability and symmetry, which occur because of a balance between two competing mass fluxes driven by thermocapillarity and evaporation. Our studies expand our understanding of cavitation and provide new insights for phase-change phenomena at the nanoscale.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1014075109