Carbon Nanotubes and Nanotube-Based Composites: Deformation Micromechanics

Abstract

The pioneering work upon the two-dimensional graphene, a one-atom thick planar sheet of sp²-bonded carbon atoms, was awarded the Nobel Prize in Physics in 2010. Carbon nanotubes (CNTs) are related nanostructures that can be envisaged as being made by rolling the two-dimensional graphene sheets into cylinders. This gives rise to fascinating materials, which have been attracting great deal of research interest in the last two decades, due to their impressive properties and wide range of potential applications. Their applications in mechanical reinforcement and electronic device are particularly promising. The excellent mechanical properties of nanotubes are related to the strong sp² hybridized carbon-carbon bonds and the perfect hexagonal structure in the graphene sheet from which they are built up, while the unique electronic properties are due largely to the one-dimensional confinement of electronic and phonon states which results in van Hove singularities in the density of states (DOS) of nanotubes (Dresselhaus et al., 2005).

Raman spectroscopy has become an important technique to both characterise the electronic structure and follow the deformation behaviour of CNTs. This technique provides insight into their intrinsic properties and the interaction of nanotubes with the surrounding environment, as well as the mechanical reinforcing efficiency of nanotubes in composites.

This chapter aims to give a brief introduction to the structure, preparation and properties of carbon nanotubes, and to review the background and main properties of nanotube Raman bands, with an emphasis on the effect of deformation upon the Raman bands. More comprehensive reviews on the physical properties and Raman spectroscopy of CNTs can be found elsewhere (Dresselhaus et al., 2002 and Dresselhaus et al., 2005).