Microfabrication of spray-coated SWCNT film strain gauges

The fabrication, and characterization results of single-wall carbon nanotube (SWCNT) film strain gauges for potential applications as highly sensitive strain and weighing sensors on the macro-scale are presented. A batch microfabrication process was developed for practical device construction using spray-coated SWCNTs and a conventional semiconductor process. Our test results demonstrated that the proposed SWCNT film gauges have the gauge factor range of 7.0 to 16.4 for four different gauge configurations, indicating that the maximum strain sensitivity of the prototype was approximately eight times greater than that of commercial gauges. In addition, a strain sensing mechanism was presented using equivalent circuits for electrical conduction in CNT and composite films.