Electronic Smart Materials Based on Carbon Nanotube Sensors/Actuators

"Emitech, Inc. proposes an innovative approach aimed at the development of carbon nanotube (CNT)-based thin film actuators/sensors possessing gravimetric work density up to 24000 J/kg per cycle, operating at frequencies up to 1 MHz, and at temperatures upto 700 C. This new concept is based on the quantum chemical effect of nanotube dimension change under charge doping/injection.The ability to move the position of CNT Fermi level through varying the voltage applied to the gate electrode (field effect) allows to control the doping charge through shifting Fermi level with respect to the CNT charge neutrality point.Two-in-one (actuation-sensing) scheme is implemented through using field-effect geometry, where actuation takes place when varying the voltage applied to the gate electrode, with sensing being achieved by monitoring current flowing through the nanotube.Direct charge injection scheme is implemented through using carbon nanotubes as (liquid or solid) electrolyte-filled electrodes of a super-capacitor. CNT actuators of this kind have advantage of low operational voltage beneficial for many applications. Thin-film actuators based on CNTs are anticipated to gain an advantage over piezoelectric films, shape memory alloys, and active polymers in:Much higher strain and strain energy density; Wider operational frequency and operational temperature range; Ability to simply control the actuator/detector operation range and signal level; Enhanced chemical stability; Simple and robust fabricationtechnique.The current multi-million dollar market for the thin-film actuators/detectors stands up for their numerous applications in military and consumer electronics, medicine, and space industry. The advanced features inherent to CNT-based actuators are believedto make them elemental devices to build up a new generation of nano-electromechanical systems (NEMS) beneficial to the whole field of emerging technologies."