Single-wall carbon nanotubes tensile strength

Carbon Nanotubes (CNTs), the third allotrope of carbon next to diamond and graphite, were discovered in 1991. Since then, their exceptional properties, such as extremely high tensile strengths (150-180 GPa) and modulus (640 GPa to 1 TPa), "ballistic thermal conduction (>3000 W/mK for individual tubes) and exceptional electrical conductivity, have been unveiled. These properties are directly attributed to their unique structure. CNTs are long cylinders of covalently bonded carbon atoms, which look somewhat like graphene sheets that have been rolled-up into seamless tubes. The tube ends may be capped by hemi-fullerenes. Single-walled carbon nanotubes (SWCNTs) comprise only one such cylinder, while multi-walled carbon nanotubes (MWCNTs) contain a set of coaxial cylinders, see Figure 1.3. 

Li F, Cheng H M, Bai S, Su G, Dresselhaus M S, Tensile strength of single-walled carbon nanotubes directly measured from their macroscopic ropes , Appl Phys Lett,... 

Carbon nanotubes (CNTs) have remarkable modulus, tensile strength, electrical and thermal conductivities. However, the promising characteristics of CNTs have not easily found their way into applications, partly because of the difficulty in dispersing tubes into individual units. Single-walled carbon nanotubes (SWNTs) are especially difficult to disperse they tend to be synthesized in the form of bundles that are difficult to separate into individual tubes due to high van der Waals interactions. 

The first carbon nanotubes discovered in nature, such as those produced in Iijima s experiments, were multiwalled nanotuhes (MWNT). Multiwalled nanotuhes consist of a number of concentric carbon cylinders, a set of tubes nested inside each other. They are somewhat complex systems that are relatively difficult to study. An important step forward in research on carbon nanotuhes occurred in 1993, when scientists learned how to make single-walled nanotubes (SWNT). Using the simpler SWNTs, scientists have learned quite rapidly a great deal about the electrical conductivity, tensile strength, flexibility, toughness, and other physical properties of carbon nanotuhes. 

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