Mechanical properties of carbon nanotubes

A variety of outstanding experimental results on the elucidation of the ela stic properties of carbon nanotubes are fast appearing. These are based mai nly on the techniques of high-resolution transmission electron microscopy ( HRTEM) and atomic force microscopy (AFM) to determine the Young's moduli of single-wall nanotube bundles and multi-walled nanotubes, prepared by a num ber of methods. These results are confirming the theoretical predictions th at carbon nanotubes have high strength plus extraordinary flexibility and r esilience. As well as summarising the most notable achievements of theory a nd experiment in the last few years, this paper explains the properties of nanotubes in the wider context of materials science and highlights the cont ribution of our research group in this rapidly expanding field. A deeper un derstanding of the relationship between the structural order of the nanotub es and their mechanical properties will be necessary for the development of carbon-nanotube-based composites. Our research to date illustrates a quali tative relationship between the Young's modulus of a nanotube and the amoun t of disorder in the atomic structure of the walls. Other exciting results indicate that composites will benefit from the exceptional mechanical prope rties of carbon nanotubes, but that the major outstanding problem of load t ransfer efficiency must be overcome before suitable engineering materials c an be produced.