TY - JOUR
T1 - Evaporation Dynamics in Buried Nanochannels with Micropores
AU - Poudel, Sajag
AU - Zou, An
AU - Maroo, Shalabh C.
N1 - Funding Information:
This material is based upon work supported by, or in part by, the Office of Naval Research under contract/grant no. N000141812357. This work was performed in part at Cornell NanoScale Facility, an NNCI member supported by NSF grant NNCI-1542081.
Publisher Copyright:
Copyright © 2020 American Chemical Society.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/7/14
Y1 - 2020/7/14
N2 - Cross-connected buried nanochannels of height ∼728 nm, with micropores of ∼2 μm diameter present at each intersection, are used in this work to numerically and experimentally study droplet-coupled evaporation dynamics at room temperature. The uniformly structured channels/pores, along with their well-defined porosity, allow for computational fluid dynamics simulations and experiments to be performed on the same geometry of samples. A water droplet is placed on top of the sample causing water to wick into the nanochannels through the micropores. After advancing, the meniscus front stabilizes when evaporation flux is balanced with the wicking flux, and it recedes once the water droplet is completely wicked in. Evaporation flux at the meniscus interface of channels/pores is estimated over time, while the flux at the water droplet interface is found to be negligible. When the meniscus recedes in the channels, local contact line regions are found to form underneath the pores, thus rapidly enhancing evaporation flux as a power-law function of time. Temporal variation of wicking flux velocity and pressure gradient in the nanochannels is also independently computed, from which the viscous resistance variation is estimated and compared to the theoretical prediction.
AB - Cross-connected buried nanochannels of height ∼728 nm, with micropores of ∼2 μm diameter present at each intersection, are used in this work to numerically and experimentally study droplet-coupled evaporation dynamics at room temperature. The uniformly structured channels/pores, along with their well-defined porosity, allow for computational fluid dynamics simulations and experiments to be performed on the same geometry of samples. A water droplet is placed on top of the sample causing water to wick into the nanochannels through the micropores. After advancing, the meniscus front stabilizes when evaporation flux is balanced with the wicking flux, and it recedes once the water droplet is completely wicked in. Evaporation flux at the meniscus interface of channels/pores is estimated over time, while the flux at the water droplet interface is found to be negligible. When the meniscus recedes in the channels, local contact line regions are found to form underneath the pores, thus rapidly enhancing evaporation flux as a power-law function of time. Temporal variation of wicking flux velocity and pressure gradient in the nanochannels is also independently computed, from which the viscous resistance variation is estimated and compared to the theoretical prediction.
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U2 - 10.1021/acs.langmuir.0c00777
DO - 10.1021/acs.langmuir.0c00777
M3 - Article
C2 - 32527087
AN - SCOPUS:85088487459
SN - 0743-7463
VL - 36
SP - 7801
EP - 7807
JO - Langmuir
JF - Langmuir
IS - 27
ER -