Development of Carbon-Nanotube-Based Nanocomposite Strain Sensor

Abstract

This paper presents the development of carbon-nanotube-based, polymer composite films that can be used as high-sensitivity strain sensors. The films were fabricated via either melt processing or solution casting of thermoplastic polymer matrices containing low concentrations of multi-walled carbon nanotubes. The electrical resistivities of the films were measured in situ using laboratory-designed fixtures and data acquisition system. The measured resistivities were correlated with the applied strains to evaluate the sensitivity of the nanocomposite film sensor. Various types of loading mode, including tension and flexure were considered. The paper suggests that conductive network formation, thus strain sensitivity of the conductive films, can be tailored by controlling nanotube loading, degree of nanotube dispersion, and film fabrication process. The developed sensors exhibited a wide range of sensitivity, the upper limit showing nearly an order of magnitude increase compared to conventional strain gages. Military and industrial applications of the sensitivity-tunable strain sensors are presented.