In situ electron microscopy experiments on MWNTsWalt A. de Heer, Philippe Poncharal, R. Nitsche, and Z.L. Wang
Recent experiments on multiwalled carbon nanotubes in a transmission electron microscope have produced several remarkable results. The electrical contacting process of carbon nanotube fibers with a mercury droplet was monitored. These experiments verified the quantized conductance (previously observed under ambient conditions), and showed what occurs during the nanotube fiber conditioning process. Carbon nanotubes deflect when they are electrically charged near a grounded counter electrode. From the deflections it is concluded that most of the charge resides at the tip as would be expected for a conducting needle under similar circumstances. Oscillating electric fields applied to the nanotubes cause dynamic deflections and can be adjusted to produce resonances from which elastic properties can be derived. These experiments also show that thick tubes tend to be softer than thin tubes. We also demonstrate how a nanotube can be used to weigh object in the femtogram mass range. A nano-viscosity meter is also demonstrated.
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