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Long Term Electrical Characterization of Thermal Cycled Carbon Nanotube Thin Films



Since the discovery of carbon nanotubes (CNTs) in 1991, numerous applications have been found for these high aspect ratio nanostructures. The high conductivity of CNTs coupled with their high aspect ratio has led to the use as conductive filler within non-conductive polymers, for low percolation nanocomposite materials. Previous research on CNTs has widely demonstrated that their electrical properties are sensitive to strain, temperature, and chemicals on an individual scale. When blended into nanocomposites, these sensitivities are preserved with an additional contributing influence from the polymer matrix. The impact on the electrical resistance due to environmental effects of these thin films, such as temperature, must be taken into account. This research focuses on the long-term changes in electrical properties of PVDF-based CNT nanocomposites due to thermal cycling. The thin films are cycled between temperatures of -70 ºC to +80 ºC repeatedly for a period of 28 weeks. In order to segregate the response of the CNTs to thermal cycling from influences from the polymer matrices, neat CNT thin films (buckypapers) are thermal cycled in addition to that of the PVDF-based nanocomposites. Furthermore, the effects from thermal expansion of the thin films are investigated by characterizing two sets of PVDF-based nanocomposites with electrodes between the glass substrate and the thin film and on the surface of the thin film. This research will allow for future tailoring of the response of these thin films to be used as multi-functional materials. Finally, this research provides insight into what the effect of anticipated environmental conditions will have on these CNT-based nanocomposites.

doi: 10.12783/SHM2015/274

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