STRAIN SENSING BY USING PIEZORESISTIVITY OF CARBON-NANOTUBE/FLEXIBLE-EPOXY COMPOSITE

Carbon nanotube (CNT) has good electrical conductivity. Addition of a few percentages of carbon nanotube to polymer yields electrical conductivity but hardly affects the mechanical properties of polymer. This conductive polymer may be useful for sensing applications such as strain sensors and chem-resist sensors. Many researchers have reported on the electrical conductivity, but the electrical resistance change under strain of the carbon nanotube composites is not fully investigated. In this study, the electrical resistance change under strain of CNT/flexible-epoxy composites was investigated experimentally and then the feasibility as large-strain sensors was demonstrated. The mechanism of the electrical resistance change under strain of CNT/polymer composites was discussed by using electrical circuit simulation based on a percolation network model and tunnelling effect between CNTs.