Perspective of nanotube sensors and nanotube actuators

The state of the art of nanotube sensors and nanotube actuators are overviewed according to the physical properties/effects (large aspect ratio, ultra-high elasticity, lower onset field emission, ultra-small interlayer friction, etc.) applied, number of nanotubes (single, double or multiple-array, fiber, film and bulk) involved, and configurations of nanotubes (cantilevered, supported, opened or telescoped) adopted by focusing on our recent effort at this challenging field. Deflection of cantilevered individual nanotubes based mass flow sensors, pico-Newton force sensors, and femtogram mass sensors, field emission of a cantilevered nanotube based approaching sensors, resistance variation of telescoping single nanotubes based variable resistors/position sensors, resistance variation of cantilevered dual nanotube based thermal probes, and our preliminary works on telescoping nanotube linear actuators are introduced and several typical examples are reviewed in this report.