Direct Mechanical Measurement of the Tensile Strength and Elastic Modulus of Multiwalled Carbon Nanotubes

The discovery of fullerine-related carbon nanotube structures in 1991 [1] has renewed hopes of approaching the theoretical limit of tensile strength.Such structures grow as concentric cylinders and are nearly defect-free.Indirect measurements of the mechanical properties of these nanotubes have yielded very high moduli (Table 1).Direct tensile testing of individual tubes, however, has proved challenging, however, due to their extremely small size.We have developed a tensile testing stage for this purpose, using microfabrication techniques.This device enables the direct application of a tensile strain to individual nanotubes while they are viewed in a transmission electron microscope.Carbon nanotubes were synthesized by arc discharge using a B-doped carbon anode [2].The tensile testing device was fabricated from silicon utilizing microfabrication techniques.Tension was applied utilizing a piezoelectric manipulation holder, fabricated in-house, the details of which have been provided earlier [3][4][5].