SENSITIVE LOAD SENSOR BASED ON PIEZORESISTIVE PROPERTIES OF MULTI-WALLED CARBON NANOTUBE

The fabrication of a micro-electro-mechanical systems (MEMS) piezoresistive load sensor is reported. The sensor has the shape of a cantilever beam on a paper substrate. Printable multi-walled carbon nanotube (MWCNT) ink was fabricated to be used as a sensing component, because of its excellent piezoresistive and electromechanical properties.. The results show that using MWCNT ink with proper sonication duration can result in a considerable force range and gauge factor for the fabricated sensor, which are two important designing factors. The results illustrated a linear resistance change with the applied forces. The force range, force resolution, and sensitivity were found to be 25 mN, 60 mu N, and 1.6 mV mN-1, respectively. Furthermore, the effects of sonication time, number of printing, and temperature on the ink resistance are experimentally studied. Finally, in order to decrease the noise levels monolithic integration of a signal-processing circuit was used. This sensor is inexpensive, simple to fabricate, light-weighted, and disposable.