Investigation of Double Walled Carbon Nanotubes for Mass Sensing

This paper deals with studying the mass sensing characteristics of Double Walled carbon Nanotubes (DWCNT) using a continuum mechanics based approach. The interlayer separation in the form of Van der Waals interaction is modelled using characteristic spring element. The inner and outer walls of the nanotube are modelled as elastic beams with a spring element connecting the two layers. Two types of boundary conditions, i.e. cantilever and bridged are considered for the purpose of analysis. This analysis explores the resonant frequency shift of Double walled Carbon Nanotubes caused by the changes in the size in terms of length and masses. The results have shown that the dynamic characteristics are influenced by the change in length as well as masses attached to the centre and at the tip of DWCNT. The results also indicate that the mass sensing characteristics of DWCNT based nano balances can reach upto 0.1 Zeptogram. This investigation is further useful in the applications involving oscillators and sensors based on nano electromechanical devices vibrating at very high frequencies in the order of THz.