Carbon Nanotubes and Graphene-Based Sensors for Human and Structural Health Monitoring

Abstract

In modern life, strain sensors have become important due to their capability to detect the strain in low as well as high strain level, and to respond and convert mechanical movement into the electrical signals. Recently, the unconventional carbon-based nanostructures such as carbon nanotubes (CNTs) and graphene for strain sensing application have been widely growing due to their extremely strong mechanical properties such as stiffness and ductility, etc. as well as excellent electrical conductivity and piezoresistive characteristics. This chapter critically discusses the state-of-the-art CNT and graphene-based strain sensors which emphasize the fabrication method of strain sensors and their performances in terms of sensitivity and maximum strain, and this also presents some new concepts of the development in the smart structural and human health monitoring systems. The first section of this chapter provides a brief overview of the fundamentals of strain-sensing properties, theoretical aspects and their potential in physical and biosensing monitoring. In the next section, brief history, structure, properties and synthesis of CNTs and graphene and the fabrication of strain sensors and the measurements will be discussed in detail. Finally, the future outlook of the strain sensors in structural and human health monitoring systems and the challenges that affect the commercialization of the strain-sensing materials are addressed. This chapter contains the theory to encourage the researchers in the implementation of these methodologies and techniques in structural and human health monitoring in their research.