Strain Microsensors Based on Carbon Nanotube/Polyimide Thin Films

The work shows the process for the fabrication of strain sensors using a 5 µm thick polyimide film loaded with 3 % weight carbon nanotubes as piezoresistive material. The sensors were produced using standard photolithography techniques, which allowed a reliable structuring of meanders with a linewidth of 50 µm and a line aspect ratio of 1:10. The thin film sensors were tested under tensile 1% strain for their characterization. The gauge factor of the produced sensors was k ~ 30. The sensors exhibited a slight drift of their electrical resistance after repeated tensile cycles. It was also noticed that their electrical resistance is influenced by the temperature with a negative dependence. These results help to establish the possibilities of integrating polymer nanocomposites for the development of strain sensors.