Atomistic modeling of carbon nanotube-based mechanical sensors

This article provides an overview of our recent studies on single-walled carbon nanotube-based sensors for measuring mass, strain, pressure, and temperature at the nanoscale. The carbon nanotube in a cantilevered or bridged configuration is simulated by an atomistic modeling, the molecular structural mechanics method. The principle of sensing is based on the resonant frequency shift of a carbon nanotube resonator when it is subjected to changes in attached mass, external loading, or temperature. The results indicate that a logarithmically linear relationship exists between the resonant frequency and the attached mass when the mass is larger than 10(-20) g. The resonant frequency shifts are shown to be linearly dependent on the applied axial strain and the applied pressure, and approximate linearity exists between the resonant frequency shift and temperature. The sensing capability of carbon nanotube-based sensors far exceeds that of current microsensors and the sensitivities can be enhanced with the use of small size carbon nanotubes.