Journal ArticleDOI
Measurements of near-ultimate strength for multiwalled carbon nanotubes and irradiation-induced crosslinking improvements.
Bei Peng,Mark A Locascio,Peter Zapol,Shuyou Li,Steven L. Mielke,George C. Schatz,Horacio D. Espinosa +6 more
TLDR
Multiwalled carbon nanotubes with a mean fracture strength >100 GPa are reported, which exceeds earlier observations by a factor of approximately three and are in excellent agreement with quantum-mechanical estimates for nanot tubes containing only an occasional vacancy defect, and are approximately 80% of the values expected for defect-free tubes.Abstract:
The excellent mechanical properties of carbon nanotubes are being exploited in a growing number of applications from ballistic armour to nanoelectronics. However, measurements of these properties have not achieved the values predicted by theory due to a combination of artifacts introduced during sample preparation and inadequate measurements. Here we report multiwalled carbon nanotubes with a mean fracture strength >100 GPa, which exceeds earlier observations by a factor of approximately three. These results are in excellent agreement with quantum-mechanical estimates for nanotubes containing only an occasional vacancy defect, and are ∼80% of the values expected for defect-free tubes. This performance is made possible by omitting chemical treatments from the sample preparation process, thus avoiding the formation of defects. High-resolution imaging was used to directly determine the number of fractured shells and the chirality of the outer shell. Electron irradiation at 200 keV for 10, 100 and 1,800 s led to improvements in the maximum sustainable loads by factors of 2.4, 7.9 and 11.6 compared with non-irradiated samples of similar diameter. This effect is attributed to crosslinking between the shells. Computer simulations also illustrate the effects of various irradiation-induced crosslinking defects on load sharing between the shells. The mechanical properties of carbon nanotubes rarely match the values predicted by theory owing to a combination of artefacts introduced during sample preparation and inadequate measurements. However, by avoiding chemical treatments and using high-resolution imaging, it is possible to obtain values of the mean fracture strength that exceed previous values by approximately a factor of three.read more
Citations
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Journal ArticleDOI
Carbon Nanotubes: Present and Future Commercial Applications
Michael De Volder,Michael De Volder,Michael De Volder,Sameh Tawfick,Sameh Tawfick,Ray H. Baughman,A. John Hart,A. John Hart +7 more
TL;DR: Although not yet providing compelling mechanical strength or electrical or thermal conductivities for many applications, CNT yarns and sheets already have promising performance for applications including supercapacitors, actuators, and lightweight electromagnetic shields.
Journal ArticleDOI
Ion and electron irradiation-induced effects in nanostructured materials
TL;DR: In this article, the authors review recent progress in the understanding of effects of irradiation on various zero-dimensional and one-dimensional nanoscale systems, such as semiconductor and metal nanoclusters and nanowires, nanotubes, and fullerenes.
Journal ArticleDOI
High-Strength Chemical-Vapor–Deposited Graphene and Grain Boundaries
Gwan Hyoung Lee,Gwan Hyoung Lee,Ryan Cooper,Sung Joo An,Sunwoo Lee,Arend M. van der Zande,Nicholas Petrone,Alexandra G. Hammerberg,Changgu Lee,Bryan Crawford,Warren C. Oliver,Jeffrey W. Kysar,James Hone +12 more
TL;DR: It is shown that the elastic stiffness of CVD-graphene is identical to that of pristine graphene if postprocessing steps avoid damage or rippling, and its strength is only slightly reduced despite the existence of grain boundaries.
Journal ArticleDOI
Merger of structure and material in nacre and bone - Perspectives on de novo biomimetic materials
TL;DR: In contrast to synthetic materials, evolutionary developments in biology have resulted in materials with remarkable structural properties, made out of relatively weak constituents, arranged in complex hierarchical patterns as discussed by the authors, which can exhibit superior levels of strength and toughness.
Journal ArticleDOI
Few layer graphene to reduce wear and friction on sliding steel surfaces
TL;DR: In this article, solution-processed graphene layers were used to reduce friction and wear on sliding steel surfaces in air (relative humidity, 30%), and small amounts of graphene-containing ethanol solution decreased wear by almost 4 orders of magnitude and friction coefficients by a factor of 6.
References
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