Piezoresistive effect of aligned multiwalled carbon nanotubes array

Abstract

There is a growing interest to exploit the mechanical properties of carbon nanotubes (CNTs) for electromechanical sensor as they exhibit supercompressibility, resilience and large elastic modulus. The paper presents the study of piezoresistive effect in aligned multi-walled carbon nanotube (CNT) array grown by chemical vapor deposition. When the array is compressed, individual carbon nanotubes start to buckle, which in turn decreases the array's electrical resistance. This behavior was found to be almost fully recoverable for the loading of up to 500 g with an increment of 50 g at an interval of 10 and 50 sec. The recorded drop in resistance during the application of the load is attributed to an increasing number of conduction channels in the nanotubes array. The change in the resistance was also found to increase linearly when 100 and 500 g load was applied at a temperature of 20 to 180°C. These results in higher values of piezoresistive effect, making MWCNTs array a very effective sensing element for pressure and strain sensor operating at elevated temperature. © 2011 Asian Network for Scientific Information.