Development of flexible carbon nanotube-polymer hybrid thin film for strain sensing

A strain sensing material based on carbon nanotube/polymer conductive composite layers has been fabricated by flexible transfer of density controlled carbon nanotube networks. The carbon nanotube networks are prepared by vacuum filtration and lithographically patterning photoresist on the filter membrane. The density and thickness of the carbon nanotube networks are tuned by simply controlling the volume of dilute suspension filtered through the membrane. These composites are resilient under large strain and there is a wide linear range of resistance-strain dependence. We demonstrate that the thin films with thicker CNTs networks exhibit more significant resistance-strain sensitivity under the same stain and the strain sensing material shows resistance-strain sensitivity depending only on the initial CNTs suspension volume. It may be possible to fabricate strain sensing materials in large volume for future smart device applications.