2003 Nanotechnology

NanotechnologyV 1505 Carbon Nanotube Flow Sensors. — The flow of a polar liquid over single-walled

carbon nanotube bundles induces a voltage in the sample along the direction of the flow. The observed data are fitted empirically to a logarithmic dependence of the voltage on the flow velocity over nearly six decades of velocity. The magnitude of the voltage in-duced along the nanotube depends significantly on the ionic strength of the flowing liq-uid. The potential for nanotubes as sensitive flow sensors is highlighted. It is believed that this sensor can be scaled down to length dimensions of the order of micrometers, making it usable in very small liquid volumes. The sensor also has high sensitivity at low velocities and a fast response time better than 1 ms. The nanotubes could also be used to make a voltage and current source in a flowing liquid environment, which may have interesting biomedical applications. — (GHOSH, S.; SOOD*, A. K.; KUMAR, N.; Science (Washington, D. C.) 299 (2003) 5609, 1042-1044; Dep. Phys., Indian Inst. Sci., Bangalore 560 012, India; Eng.) — W. Pewestorf

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