POLYMER-EMBEDDED CARBON NANOTUBE YARNS:UNVEILING THEIR PIEZORESISTIVE RESPONSE AND SENSITIVITY THROUGH PARAMETRIC STUDIES

摘要

The ability to measure strain using embedded micron-size sensors could revolutionize structural health monitoring and allow real-time monitoring of critical areas where direct access is not possible.Carbon nanotube(CNT)yarns are microscale continuous assemblies of CNTs exhibiting a piezoresistive response that could be tapped for strain measurement.The piezoresistive response of free or unconstrained CNT yarns and their sensitivity or gauge factor have been extensively studied including the effects played by the angle of twist and porosity,strain level,strain rate and other parameters like their geometry.The piezoresistivity of CNT yarns originates from the intrinsic resistance of the carbon nanotubes,and from the inter-tube resistance including that of nanotubes in physical contact or the tunneling resistance when nanotubes are separated by a small gap.Initial results on the piezoresistive response of CNT yarns integrated or embedded in polymeric matrices forming monofilament composites where the yarns are constrained are also available5.This study includes experimental results on the piezoresistive response of polymer-embedded CNT yarns(CNT yarn monofilament composites)and the comparison with that of free CNT yarns subjected to various loading conditions.Some of the most relevant parameters that affect the piezoresistive response of free CNT yarns including the strain rate and strain level are also considered in this study.