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Published June 17, 2014 | public
Journal Article Open

Physicochemical Characteristics and Droplet Impact Dynamics of Superhydrophobic Carbon Nanotube Arrays


The physicochemical and droplet impact dynamics of superhydrophobic carbon nanotube arrays are investigated. These superhydrophobic arrays are fabricated simply by exposing the as-grown carbon nanotube arrays to a vacuum annealing treatment at a moderate temperature. This treatment, which allows a significant removal of oxygen adsorbates, leads to a dramatic change in wettability of the arrays, from mildly hydrophobic to superhydrophobic. Such change in wettability is also accompanied by a substantial change in surface charge and electrochemical properties. Here, the droplet impact dynamics are characterized in terms of critical Weber number, coefficient of restitution, spreading factor, and contact time. Based on these characteristics, it is found that superhydrophobic carbon nanotube arrays are among the best water-repellent surfaces ever reported. The results presented herein may pave a way for the utilization of superhydrophobic carbon nanotube arrays in numerous industrial and practical applications, including inkjet printing, direct injection engines, steam turbines, and microelectronic fabrication.

Additional Information

© 2014 American Chemical Society. Received: October 3, 2013; Revised: May 25, 2014. Publication Date (Web): May 27, 2014. This work was supported by The Office of Naval Research under grant #N00014-11-1-0031 and The Fletcher-Jones Foundation under grant #9900600.The authors gratefully acknowledge support and infrastructure provided for this work by the Charyk Laboratory for Bioinspired Design at the California Institute of Technology, the Kavli Nanoscience Institute at the California Institute of Technology, the Molecular Materials Research Center of the Beckman Institute at the California Institute of Technology, and the Analytical Facility Division of Geological and Planetary Sciences of the California Institute of Technology. The authors also acknowledge C. Y. Shu and A. Ghosh for their valuable assistance in conducting the droplet impact dynamic experiments, B. J. Lyon for the assistance in conducting the superhydrophobic lifetime measurement, and Prof. George Rossman for providing an access to the Raman spectrometer.

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Supplemental Material - la501360t_si_001.pdf


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August 20, 2023
August 20, 2023