Strength and Breaking Mechanism of Multiwalled Carbon Nanotubes Under Tensile Load

TLDR

The tensile strengths of individual multiwalled carbon nanotubes were measured using a nanostressing stage inside a scanning electron microscope, with the loading experiment performed and recorded entirely within the microscope. The nanotubes failed by rupture of the outermost layer, with tensile strengths ranging from 11 to 63 GPa and outer‑layer Young’s modulus between 270 and 950 GPa, and electron‑microscopic examination of the fragments revealed diverse structures such as ribbons, waves, and partial radial collapse.

Abstract

The tensile strengths of individual multiwalled carbon nanotubes (MWCNTs) were measured with a "nanostressing stage" located within a scanning electron microscope. The tensile-loading experiment was prepared and observed entirely within the microscope and was recorded on video. The MWCNTs broke in the outermost layer ("sword-in-sheath" failure), and the tensile strength of this layer ranged from 11 to 63 gigapascals for the set of 19 MWCNTs that were loaded. Analysis of the stress-strain curves for individual MWCNTs indicated that the Young's modulus E of the outermost layer varied from 270 to 950 gigapascals. Transmission electron microscopic examination of the broken nanotube fragments revealed a variety of structures, such as a nanotube ribbon, a wave pattern, and partial radial collapse.