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Electrowetting in carbon nanotubes
Mechanical deformations in carbon nanotubes
Electrowetting in carbon nanotubes
Liquid metals have high surface tensions and normally do not wet most solids. In particular, liquid mercury does not spontaneously wet or enter carbon nanotubes, as its surface tension of 475 mN/m is much higher than the threshold value of ~180 mN/m below which wetting can occur. However, the application of an electrical potential can lower the surface tension and cause electrowetting. We have demonstrated that the electrically activated wetting is indeed possible, which has important implications for nanofluidics, nanoprobes, and manipulation at the nanoscale. Electrowetting in carbon nanotubes may be employed to pump fluids in attoliter quantities or form metal nanowires from molten metals.
•Electrowetting in carbon nanotubes J.Y. Chen, A. Kutana, C.P. Collier, and K.P. Giapis, Science 310, 1480 (2005) (link)
Caltech news release
"Mercurial wetting", Science news clip
in Physorg.com news
in nanotechweb news
•Atomistic simulations of electrowetting in carbon nanotubes A. Kutana, K.P. Giapis, Nano Letters 6, 656 (2006) (link)
Movie of molecular dynamics simulation of mercury entering a SWNT due to electrowetting:
Mechanical deformations in carbon nanotubes
Carbon nanotubes possess remarkable mechanical properties, making them ideal candidates for use in nanoelectromechanical systems (NEMS). Detailed quantitative description of the elastic properties of nanotubes is needed for future technological applications. This work deals with molecular dynamics (MD) simulations of bending deformations in nanotubes. A transient bending regime (TBR) is discovered in single-walled nanotubes with diameters ~2 nm and above. The transient regime is characterized by a gradual and controllable flattening of the nanotube cross section at the bending site, and can be used to restrict the liquid flow in a nanotube used as a conduit for nanofluidic transport.
Additionally, large single-walled nanotubes display bending hysteresis due to van der Waals attraction between the tube walls at the kinked site.
•A. Kutana, K. P. Giapis A transient deformation regime in bending of single-walled carbon nanotubes, Phys. Rev. Lett. 97, 245501 (2006) (link)
Caltech news release
Physorg news release
This paper has also appeared in the December 25, 2006 issue of the Virtual Journal of Nanoscale Science & Technology, v. 14, issue 26, http://www.vjnano.org/
• A. Kutana, K. P. Giapis, J. Y. Chen, C. P. Collier Amplitude Response of Single-Wall Carbon Nanotube Probes during Tapping Mode Atomic Force Microscopy: Modeling and Experiment, Nano Letters 6, 1669 (2006) (link)
Movie of MD simulation of pure bending of a (30,30) SWNT:
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