TY - JOUR
T1 - Liquid Imbibition in Ceramic-Coated Carbon Nanotube Films
AU - Zhao, Hangbo
AU - Jacob, Christine
AU - Stone, Howard A.
AU - Hart, A. John
N1 - Funding Information:
Financial support to H.Z. and A.J.H., and for experiments was provided by the MIT Center for Clean Water and Clean Energy supported by the King Fahd University of Petroleum and Minerals, the Air Force Office of Scientific Research (FA9550-16-1-0011), a Seed Grant from the MIT Energy Initiative, and faculty startup funds from the MIT Department of Mechanical Engineering. C.J. was supported by the Lockheed Martin Doctoral Fellowship program. Funding for the ALD system was provided in part by the MIT Department of Mechanical Engineering Papallardo Fund. We thank Justin Beroz for valuable discussions and Yue Guan for assistance with the experimental setup. Catalyst deposition and plasma treatment were performed at the MIT Microsystems Technology Laboratories (MTL). Electron microscopy was performed at the MIT Center for Materials Science and Engineering (CMSE).
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/12/6
Y1 - 2016/12/6
N2 - Understanding of the liquid imbibition dynamics in nanoporous materials is important to advances in chemical separations, phase change heat transfer, electrochemical energy storage, and diagnostic assays. We study the liquid imbibition behavior in films of ceramic-coated vertically aligned carbon nanotubes (CNTs). The nanoscale porosity of the films is tuned by conformal ceramic coating via atomic layer deposition (ALD), enabling stable liquid imbibition and precise measurement of the imbibition dynamics without capillary densification of the CNTs. We show that the imbibition rate decreases as the ceramic coating thickness increases, which effectively changes the CNT-CNT spacing and therefore decreases the permeability. We derive a model, based on Darcy's law, that incorporates an expression for the permeability of nanoscale post arrays, and we show that the model fits the experimental results with high accuracy. The tailorable porosity, along with controllable surface wettability and mechanical stability of coated CNTs, suggest their suitability for application-guided engineering, and for further investigation of imbibition behavior at finer length scales.
AB - Understanding of the liquid imbibition dynamics in nanoporous materials is important to advances in chemical separations, phase change heat transfer, electrochemical energy storage, and diagnostic assays. We study the liquid imbibition behavior in films of ceramic-coated vertically aligned carbon nanotubes (CNTs). The nanoscale porosity of the films is tuned by conformal ceramic coating via atomic layer deposition (ALD), enabling stable liquid imbibition and precise measurement of the imbibition dynamics without capillary densification of the CNTs. We show that the imbibition rate decreases as the ceramic coating thickness increases, which effectively changes the CNT-CNT spacing and therefore decreases the permeability. We derive a model, based on Darcy's law, that incorporates an expression for the permeability of nanoscale post arrays, and we show that the model fits the experimental results with high accuracy. The tailorable porosity, along with controllable surface wettability and mechanical stability of coated CNTs, suggest their suitability for application-guided engineering, and for further investigation of imbibition behavior at finer length scales.
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U2 - 10.1021/acs.langmuir.6b03661
DO - 10.1021/acs.langmuir.6b03661
M3 - Article
C2 - 27934531
AN - SCOPUS:85002656936
SN - 0743-7463
VL - 32
SP - 12686
EP - 12692
JO - Langmuir
JF - Langmuir
IS - 48
ER -