Nanocomposite strain sensors: Study of electrical and thermal properties

The strain sensing ability of single-walled carbon nanotubes (SWNTs) in buckypaper are explored using Raman spectroscopy. This sensing ability is also examined based on electrical properties using SWNTs in buckypaper, a nanocomposite (2% wt.) from National Aeronautics and Space Administration (NASA), and a PVDF-DWNT (polyvinylidene-fluoride double-walled) composite (0.1% wt.). The voltage and resistance change is measured by a four-point probe setup; with the voltage or resistance calculated using Ohm's law. Compressive and tensile forces are applied using an MTS servohydraulic testing machine. The effect of temperature on the NASA specimen is also studied. Results will show an approximately linear resistance change in the buckpaper and NASA specimen when subjected to tension and compression forces, while the PVDF sample will not show this because the % wt. is below the percolation value (0.19%) necessary to achieve conductivity. A linear relationship between temperature and change in resistance in NASA specimen is shown.