Application of multi-walled carbon nanotube film strain gauge on metallic surface

In this work we investigated the possibility to use CNT film strain gauge on the metallic surface. Brass cantilever was used to investigate the tensile and compressive strain sensing property of MWCNT films. Two types of isolation layer were used between MWCNT film and brass cantilever, ink jet film and aerosol varnish. From the measurements we found higher gauge factor can be obtained by using aerosol varnish as isolation layer due to a better transfer of loading. CNT films produced by two types of MWCNTs have different conductivity and gauge factor. By choosing the suitable CNTs, compromise should thus be made between conductivity and reproducibility as well as the sensitivity depending on the different applications. MWCNT-polymer (Polyethylene oxide, PEO) composites with different MWCNT weight fractions were also produced to obtain higher and tailored gauge factor. Higher gauge factor of 10 can be achieved for MWCNT-PEO composite film with 2.5wt% MWCNTs. Tailored gauge factor can be achieved by changing the MWCNT concentration.