Tribological properties of carbon nanotube bundles predicted from atomistic simulations
TL;DR: In this paper, the authors investigate the responses of bundles of single-walled carbon nanotubes to compressive and shear forces between two sliding diamond surfaces and determine the forces on the atoms in the simulations using a many-body reactive empirical potential for hydrocarbons coupled to Lennard-Jones potentials.
About: This article is published in Surface Science.The article was published on 2001-07-20. It has received 98 citations till now. The article focuses on the topics: Mechanical properties of carbon nanotubes & Carbon nanotube.
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TL;DR: The exciting successes in taming molecular-level movement thus far are outlined, the underlying principles that all experimental designs must follow, and the early progress made towards utilizing synthetic molecular structures to perform tasks using mechanical motion are highlighted.
Abstract: The widespread use of controlled molecular-level motion in key natural processes suggests that great rewards could come from bridging the gap between the present generation of synthetic molecular systems, which by and large rely upon electronic and chemical effects to carry out their functions, and the machines of the macroscopic world, which utilize the synchronized movements of smaller parts to perform specific tasks. This is a scientific area of great contemporary interest and extraordinary recent growth, yet the notion of molecular-level machines dates back to a time when the ideas surrounding the statistical nature of matter and the laws of thermodynamics were first being formulated. Here we outline the exciting successes in taming molecular-level movement thus far, the underlying principles that all experimental designs must follow, and the early progress made towards utilizing synthetic molecular structures to perform tasks using mechanical motion. We also highlight some of the issues and challenges that still need to be overcome.
2,301 citations
TL;DR: In der Natur spielen gesteuerte Bewegungen auf molekularer Ebene bei vielen Prozessen eine Schlusselrolle as mentioned in this paper.
Abstract: In der Natur spielen gesteuerte Bewegungen auf molekularer Ebene bei vielen Prozessen eine Schlusselrolle. Das Schliesen der Lucke zwischen der aktuellen Generation synthetischer Verbindungen, bei denen hauptsachlich elektronische und chemische Effekte genutzt werden, und makroskopischen Maschinen, deren Funktionsfahigkeit auf der synchronisierten Bewegung von Maschinenteilen beruht, ware ein groser Erfolg. Dieses Forschungsgebiet wird derzeit intensiv bearbeitet und wachst auserordentlich schnell. Die ersten Uberlegungen zu molekularen Maschinen reichen allerdings weiter zuruck in die Vergangenheit, in eine Zeit, in der die Konzepte vom statistischen Verhalten der Materie und die Gesetze der Thermodynamik formuliert wurden. Wir umreisen hier die Erfolgsgeschichte der Bandigung molekularer Bewegungen, der Beherrschung der grundlegenden Prinzipien, an denen sich das Design zu orientieren hat, und der Fortschritte bei der Anwendung synthetischer Systeme, die durch mechanische Bewegung Aufgaben verrichten konnen. Ferner werden wir auf einige ungeloste Probleme eingehen.
507 citations
TL;DR: The improvement in FC, AW, and EP properties of nanofluids is respectively by 80, 33, and 40% compared with base oil and can be attributed to the nanobearing mechanism of graphene in engine oil and ultimate mechanical strength of graphene.
Abstract: Ultrathin graphene (UG) has been prepared by exfoliation of graphite oxide by a novel technique based on focused solar radiation. Graphene based engine oil nanofluids have been prepared and their frictional characteristics (FC), antiwear (AW), and extreme pressure (EP) properties have been evaluated. The improvement in FC, AW, and EP properties of nanofluids is respectively by 80, 33, and 40% compared with base oil. The enhancement can be attributed to the nanobearing mechanism of graphene in engine oil and ultimate mechanical strength of graphene.
362 citations
TL;DR: In this article, the tribological behavior of MoS 2 multi-wall nanotubes (MWNTs) as a potential additive in lubricating oils was evaluated in the boundary-lubrication regime under a contact pressure of 1 GPa (Hertz, max) and a sliding velocity of 0.005 m/s using a ball-on-disc tribotester.
243 citations
TL;DR: In this article, highly anisotropic tribological behavior of multi-walled nanotube films oriented in mutually orthogonal directions was examined and the average values of coefficient of friction varied from extremely high values (μ=0.795) for vertically aligned nanotubes grown on rigid substrates to very low values (m = 0.090) for distributed flat on the same substrates.
Abstract: This report examines highly anisotropic tribological behavior of multi-walled nanotube films oriented in mutually orthogonal directions. The average values of coefficient of friction varied from extremely high values (μ=0.795) for vertically aligned nanotubes grown on rigid substrates to very low values (μ=0.090) for nanotubes dispersed flat on the same substrates. The results were insensitive to humidity, in contrast to graphite materials, and indicate that nanotubes could be utilized as both low and high frictional surfaces.
128 citations
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11 Feb 1988TL;DR: In this paper, the gear predictor -corrector is used to calculate forces and torques in a non-equilibrium molecular dynamics simulation using Monte Carlo methods. But it is not suitable for the gear prediction problem.
Abstract: Introduction Statistical mechanics Molecular dynamics Monte Carlo methods Some tricks of the trade How to analyse the results Advanced simulation techniques Non-equilibrium molecular dynamics Brownian dynamics Quantum simulations Some applications Appendix A: Computers and computer simulation Appendix B: Reduced units Appendix C: Calculation of forces and torques Appendix D: Fourier transforms Appendix E: The gear predictor - corrector Appendix F: Programs on microfiche Appendix G: Random numbers References Index.
21,073 citations
TL;DR: In this article, the amplitude of the intrinsic thermal vibrations of isolated carbon nanotubes was measured in the transmission electron microscopy (TEM) and it was shown that they have exceptionally high Young's moduli, in the terapascal (TPa) range.
Abstract: CARBON nanotubes are predicted to have interesting mechanical properties—in particular, high stiffness and axial strength—as a result of their seamless cylindrical graphitic structure1–5. Their mechanical properties have so far eluded direct measurement, however, because of the very small dimensions of nanotubes. Here we estimate the Young's modulus of isolated nanotubes by measuring, in the transmission electron microscope, the amplitude of their intrinsic thermal vibrations. We find that carbon nanotubes have exceptionally high Young's moduli, in the terapascal (TPa) range. Their high stiffness, coupled with their low density, implies that nanotubes might be useful as nanoscale fibres in strong, lightweight composite materials.
5,207 citations
TL;DR: An empirical many-body potential-energy expression is developed for hydrocarbons that can model intramolecular chemical bonding in a variety of small hydrocarbon molecules as well as graphite and diamond lattices based on Tersoff's covalent-bonding formalism with additional terms that correct for an inherent overbinding of radicals.
Abstract: An empirical many-body potential-energy expression is developed for hydrocarbons that can model intramolecular chemical bonding in a variety of small hydrocarbon molecules as well as graphite and diamond lattices. The potential function is based on Tersoff's covalent-bonding formalism with additional terms that correct for an inherent overbinding of radicals and that include nonlocal effects. Atomization energies for a wide range of hydrocarbon molecules predicted by the potential compare well to experimental values. The potential correctly predicts that the \ensuremath{\pi}-bonded chain reconstruction is the most stable reconstruction on the diamond {111} surface, and that hydrogen adsorption on a bulk-terminated surface is more stable than the reconstruction. Predicted energetics for the dimer reconstructed diamond {100} surface as well as hydrogen abstraction and chemisorption of small molecules on the diamond {111} surface are also given. The potential function is short ranged and quickly evaluated so it should be very useful for large-scale molecular-dynamics simulations of reacting hydrocarbon molecules.
3,588 citations
TL;DR: With properly chosen parameters, the model provides a remarkably accurate ``roadmap'' of nanotube behavior beyond Hooke's law.
Abstract: Carbon nanotubes subject to large deformations reversibly switch into different morphological patterns. Each shape change corresponds to an abrupt release of energy and a singularity in the stress-strain curve. These transformations, simulated using a realistic many-body potential, are explained by a continuum shell model. With properly chosen parameters, the model provides a remarkably accurate ``roadmap'' of nanotube behavior beyond Hooke's law.
2,458 citations
TL;DR: The results demonstrate the nature of rheology, on nanometer scales, in composite media and flow-induced anisotropy produced by the cutting process and suggest that nanotubes have excellent mechanical properties.
Abstract: A simple technique is described here that produces aligned arrays of carbon nanotubes. The alignment method is based on cutting thin slices (50 to 200 nanometers) of a nanotube-polymer composite. With this parallel and well-separated configuration of nanotubes it should be possible to measure individual tube properties and to demonstrate applications. The results demonstrate the nature of rheology, on nanometer scales, in composite media and flow-induced anisotropy produced by the cutting process. The fact that nanotubes do not break and are straightened after the cutting process also suggests that they have excellent mechanical properties.
1,511 citations