Structure-property-processing relationships of single-wall carbon nanotube thin film piezoresistive sensors

In an investigation of structure-property-processing relationships for SWCNT thin film piezoresistive sensors, the gauge factor of the sensors for a small tensile deformation (less than 2% strain) was found to be close to unity and showed negligible dependence on the film thickness and SWCNT bundle length (L) and diameter (d). However, for a large tensile deformation (20-30% strain), the film thickness and the microstructure of SWCNTs had a compounding effect on the piezoresistive behavior. A gauge factor of similar to 5 was obtained for the sensors fabricated with SWCNT bundles of short length and thin diameter (L = 549 nm and d = 3.7 nm) with thicker films. Furthermore, the gauge factor of the sensors was found inversely proportional to the excluded volume V-ex of SWCNT bundles (V-ex proportional to 1/L-2 d). (C) 2013 Elsevier Ltd. All rights reserved.