Development of MWCNT-based strain sensor using flexible substrate

Highly sensitive two-dimensional strain sensor, which consists of area-arrayed fine bundles of multi-walled carbon nanotubes (MWCNTs), has been developed by applying MEMS technology. Area-arrayed MWCNT bundles were grown on a substrate by CVD technique. When a compressive load was applied to the bundle, the electrical resistance of the bundle increased monotonically due to the change of the electronic band structure of the deformed CNT. By measuring the change of the resistance of each bundle, the two-dimensional distribution of the applied pressure was detected precisely. In the previous study, it was found that MWCNT bundle deformed repeatedly in the strain range up to 60%. Thus, in this study, the deformation behaviour of the MWCNT bundle on a flexible substrate, which is effective for rough surface, was observed. It was confirmed that the MWCNT bundle coated by PDMS showed elastic deformation under the application of axial compressive load of 60%, and the allowable maximum load was 3 mN.