Superlubricity

Last updated
Foam in an egg carton which simulates the atomic surface structure of graphite, commensurable due to alignment in this photo Incommensurabilite 2.jpg
Foam in an egg carton which simulates the atomic surface structure of graphite, commensurable due to alignment in this photo
Incommensurable due to twisting, so the valleys and hills don't line up Incommensurabilite 4.jpg
Incommensurable due to twisting, so the valleys and hills don't line up

In physics (specifically tribology), superlubricity is a regime of motion in which friction vanishes or very nearly vanishes. However, a "vanishing" friction level is not clear, which makes the term vague. As an ad hoc definition, a kinetic coefficient of friction less than 0.01 can be adopted. [1] This definition also requires further discussion and clarification.

Contents

Superlubricity may occur when two crystalline surfaces slide over each other in dry incommensurate contact. This effect, also called structural lubricity, was suggested in 1991 and verified with great accuracy between two graphite surfaces in 2004. [2] The atoms in graphite are oriented in a hexagonal manner and form an atomic hill-and-valley landscape, which looks like an egg-crate. When the two graphite surfaces are in registry (every 60 degrees), the friction force is high. When the two surfaces are rotated out of registry, the friction is greatly reduced. This is like two egg-crates which can slide over each other more easily when they are "twisted" with respect to each other.

Observation of superlubricity in microscale graphite structures was reported in 2012, [3] by shearing a square graphite mesa a few micrometers across, and observing the self-retraction of the sheared layer. Such effects were also theoretically described [4] for a model of graphene and nickel layers. This observation, which is reproducible even under ambient conditions, shifts interest in superlubricity from a primarily academic topic, accessible only under highly idealized conditions, to one with practical implications for micro and nanomechanical devices. [5]

A state of ultralow friction can also be achieved when a sharp tip slides over a flat surface and the applied load is below a certain threshold. Such a "superlubric" threshold depends on the tip-surface interaction and the stiffness of the materials in contact, as described by the Tomlinson model. [6] The threshold can be significantly increased by exciting the sliding system at its resonance frequency, which suggests a practical way to limit wear in nanoelectromechanical systems. [7]

Superlubricity was also observed between a gold AFM tip and Teflon substrate due to repulsive Van der Waals forces and hydrogen-bonded layer formed by glycerol on the steel surfaces. Formation of the hydrogen-bonded layer was also shown to lead to superlubricity between quartz glass surfaces lubricated by biological liquid obtained from mucilage of Brasenia schreberi. Other mechanisms of superlubricity may include: [8] (a) Thermodynamic repulsion due to a layer of free or grafted macromolecules between the bodies so that the entropy of the intermediate layer decreases at small distances due to stronger confinement; (b) Electrical repulsion due to external electrical voltage; (c) Repulsion due to electrical double layer; (d) Repulsion due to thermal fluctuations. [9]

The similarity of the term superlubricity with terms such as superconductivity and superfluidity is misleading; other energy dissipation mechanisms can lead to a finite (normally small) friction force. Superlubricity is more analogous to phenomena such as superelasticity, in which substances such as Nitinol have very low, but nonzero, elastic moduli; supercooling, in which substances remain liquid until a lower-than-normal temperature; super black, which reflects very little light; giant magnetoresistance, in which very large but finite magnetoresistance effects are observed in alternating nonmagnetic and ferromagnetic layers; superhard materials, which are diamond or nearly as hard as diamond; and superlensing, which have a resolution which, while finer than the diffraction limit, is still finite.

Superlubricity at the macroscale

In 2015, a team led by Dr. Anirudha Sumant at the Argonne National Laboratory have been able to experimentally demonstrate superlubricity at true microscale for the first time. [10] The detailed experimental investigations were supported by sophisticated computational studies. Argonne scientists used Mira [supercomputer] simulating up to 1.2 million atoms for dry environments and up to 10 million atoms for humid environments. [10] The researchers used the LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) code to carry out the computationally demanding reactive molecular dynamics simulations. This team optimized LAMMPS and its implementation of ReaxFF by adding OpenMP threading, replacing MPI point-to-point communication with MPI collectives in key algorithms, and leveraging MPI I/O. Altogether, these enhancements allowed the code to perform twice as fast as before. Dr. Sumant's research team has already acquired three US patents on superlubricity and more are in the process, which could potentially be used for applications in dry environments, such as computer hard drives, wind turbine gears, and mechanical rotating seals for microelectromechanical and nanoelectromechanical systems. Dr. Sumant gave a TEDX talk on Superlubricity. [11]

See also

Related Research Articles

<span class="mw-page-title-main">Friction</span> Force resisting sliding motion

Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction:

<span class="mw-page-title-main">Molybdenum disulfide</span> Chemical compound

Molybdenum disulfide is an inorganic compound composed of molybdenum and sulfur. Its chemical formula is MoS
2.

Whenever two objects rub together, for instance wheels on a road, gears in a motor, there is both friction and wear. Different surfaces have different amounts of friction, for instance a smooth surface compared to a rough one. How much material comes off also depends upon the surfaces, and also how much pressure is used -- for instance using sandpaper to smooth out wood. One can also add liquids such as oils or water to reduce the friction, which is called lubrication.

<span class="mw-page-title-main">Graphene</span> Hexagonal lattice made of carbon atoms

Graphene is an allotrope of carbon consisting of a single layer of atoms arranged in a hexagonal lattice nanostructure. The name is derived from "graphite" and the suffix -ene, reflecting the fact that the graphite allotrope of carbon contains numerous double bonds.

Nanotribology is the branch of tribology that studies friction, wear, adhesion and lubrication phenomena at the nanoscale, where atomic interactions and quantum effects are not negligible. The aim of this discipline is characterizing and modifying surfaces for both scientific and technological purposes.

Amir Ordacgi Caldeira is a Brazilian physicist. He received his bachelor's degree in 1973 from the Pontifícia Universidade Católica do Rio de Janeiro, his M.Sc. degree in 1976 from the same university, and his Ph.D. in 1980 from University of Sussex. His Ph.D. advisor was the Physics Nobel Prize winner Anthony James Leggett. He joined the faculty at Universidade Estadual de Campinas (UNICAMP) in 1980. In 1984 he did post-doctoral work at the Kavli Institute for Theoretical Physics (KITP) at University of California, Santa Barbara and at the Thomas J. Watson Research Laboratory at IBM. In 1994–1995 he spent a sabbatical at the University of Illinois at Urbana-Champaign. He is currently a full professor at Universidade Estadual de Campinas. He was the recipient of the Wataghin Prize, from Universidade Estadual de Campinas, for his contributions to theoretical physics in 1986.

<span class="mw-page-title-main">Marvin L. Cohen</span> American physicist

Marvin Lou Cohen is an American theoretical physicist. He is a University Professor of Physics at the University of California, Berkeley. Cohen is a leading expert in the field of Condensed Matter Physics. He is highly cited and most widely known for his seminal work on the electronic structure of solids.

William H. Bassichis is an American physicist. He has been a physics professor at Texas A&M University since 1970. He is the author of a series of undergraduate physics textbooks titled Don't Panic, which is used by some universities across North America. Before teaching at Texas A&M, Bassichis has done research at the Weizmann Institute of Science, the Centre d'études Nucléaires de Saclay, and the Lawrence Livermore Laboratory. He has also taught at MIT.

<span class="mw-page-title-main">Electron beam ion trap</span>

Electron beam ion trap (EBIT) is an electromagnetic bottle that produces and confines highly charged ions. An EBIT uses an electron beam focused with a powerful magnetic field to ionize atoms to high charge states by successive electron impact.

The Tomlinson model, also known as the Prandtl–Tomlinson Model, is one of the most popular models in nanotribology widely used as the basis for many investigations of frictional mechanisms on the atomic scale. Essentially, a nanotip is dragged by a spring over a corrugated energy landscape. A "frictional parameter" η can be introduced to describe the ratio between the energy corrugation and the elastic energy stored in the spring. If the tip-surface interaction is described by a sinusoidal potential with amplitude V0 and periodicity a then

Patrick A. Lee is a professor of physics at the Massachusetts Institute of Technology (MIT).

Spin-polarized electron energy loss spectroscopy or SPEELS is a technique that is mainly used to measure the dispersion relation of the collective excitations, over the whole Brillouin zone.

Philippe Guyot-Sionnest is a professor at the University of Chicago appointed jointly in the departments of physics and chemistry. He works in the field of colloidal semiconductors and metal nanocrystals.

In physical cosmology, warm inflation is one of two dynamical realizations of cosmological inflation. The other is the standard scenario, sometimes called cold inflation.

Bilayer graphene is a material consisting of two layers of graphene. One of the first reports of bilayer graphene was in the seminal 2004 Science paper by Geim and colleagues, in which they described devices "which contained just one, two, or three atomic layers"

Band-gap engineering is the process of controlling or altering the band gap of a material. This is typically done to semiconductors by controlling the composition of alloys, constructing layered materials with alternating compositions, or by inducing strain either epitaxially or topologically. A band gap is the range in a solid where no electron state can exist. The band gap of insulators is much larger than in semiconductors. Conductors or metals have a much smaller or nonexistent band gap than semiconductors since the valence and conduction bands overlap. Controlling the band gap allows for the creation of desirable electrical properties.

A rapidly increasing list of graphene production techniques have been developed to enable graphene's use in commercial applications.

<span class="mw-page-title-main">Discovery of graphene</span>

Single-layer graphene was first unambiguously produced and identified in 2004, by the group of Andre Geim and Konstantin Novoselov, though they credit Hanns-Peter Boehm and his co-workers for the experimental discovery of graphene in 1962; while it had been explored theoretically by P. R. Wallace in 1947. Boehm et al. introduced the term graphene in 1986.

Toshiki Tajima is a Japanese theoretical plasma physicist known for pioneering the laser wakefield acceleration technique with John M. Dawson in 1979. The technique is used to accelerate particles in a plasma and was experimentally realized in 1994, for which Tajima received several awards such as the Nishina Memorial Prize (2006), the Enrico Fermi Prize (2015), the Robert R. Wilson Prize (2019), the Hannes Alfvén Prize (2019) and the Charles Hard Townes Award (2020).

<span class="mw-page-title-main">Liliane Léger</span> French physicist

Liliane Léger née Quercy is a French physicist. Her research considers polymers and the molecular mechanisms of adhesion. She was awarded the Groupe Français d’Études et d’Applications des Polymères Prix d’Honneur in 2021.

References

  1. ↑ Müser, Martin H. (2015-01-01). "Theoretical Studies of Superlubricity". In Gnecco, Enrico; Meyer, Ernst (eds.). Fundamentals of Friction and Wear on the Nanoscale. NanoScience and Technology. Springer International Publishing. pp. 209–232. doi:10.1007/978-3-319-10560-4_11. ISBN   9783319105598.
  2. ↑ Dienwiebel, Martin; Verhoeven, Gertjan S.; Pradeep, Namboodiri; Frenken, Joost W. M.; Heimberg, Jennifer A.; Zandbergen, Henny W. (2004-03-24). "Superlubricity of Graphite" (PDF). Physical Review Letters. American Physical Society (APS). 92 (12): 126101. Bibcode:2004PhRvL..92l6101D. doi:10.1103/physrevlett.92.126101. ISSN   0031-9007. PMID   15089689.
  3. ↑ Liu, Ze; Yang, Jiarui; Grey, Francois; Liu, Jefferson Zhe; Liu, Yilun; Wang, Yibing; Yang, Yanlian; Cheng, Yao; Zheng, Quanshui (2012-05-15). "Observation of Microscale Superlubricity in Graphite". Physical Review Letters. American Physical Society (APS). 108 (20): 205503. arXiv: 1104.3320 . Bibcode:2012PhRvL.108t5503L. doi:10.1103/physrevlett.108.205503. ISSN   0031-9007. PMID   23003154. S2CID   119192523.
  4. ↑ Superlubricity through graphene multilayers between Ni(111) surfaces
  5. ↑ Graphite super lube works at micron scale Philip Robinson, Chemistry World, 28 May 2012
  6. ↑ Socoliuc, A.; Bennewitz, R.; Gnecco, E.; Meyer, E. (2004-04-01). "Transition from Stick-Slip to Continuous Sliding in Atomic Friction: Entering a New Regime of Ultralow Friction". Physical Review Letters. American Physical Society (APS). 92 (13): 134301. Bibcode:2004PhRvL..92m4301S. doi:10.1103/physrevlett.92.134301. ISSN   0031-9007. PMID   15089616.
  7. ↑ Socoliuc, Anisoara; Gnecco, Enrico; Maier, Sabine; Pfeiffer, Oliver; Baratoff, Alexis; Bennewitz, Roland; Meyer, Ernst (2006-07-14). "Atomic-Scale Control of Friction by Actuation of Nanometer-Sized Contacts". Science. American Association for the Advancement of Science (AAAS). 313 (5784): 207–210. Bibcode:2006Sci...313..207S. doi:10.1126/science.1125874. ISSN   0036-8075. PMID   16840695. S2CID   43269213.
  8. ↑ Popov, Valentin L. (2020). "Contacts With Negative Work of "Adhesion" and Superlubricity". Frontiers in Mechanical Engineering. 5. doi: 10.3389/fmech.2019.00073 .
  9. ↑ Zhou, Yunong; Wang, Anle; Müser, Martin H. (2019). "How Thermal Fluctuations Affect Hard-Wall Repulsion and Thereby Hertzian Contact Mechanics". Frontiers in Mechanical Engineering. 5. doi: 10.3389/fmech.2019.00067 .
  10. 1 2 Berman, Diana; Deshmukh, Sanket A.; Sankaranarayanan, Subramanian K. R. S.; Erdemir, Ali; Sumant, Anirudha V. (2015-06-05). "Macroscale superlubricity enabled by graphene nanoscroll formation". Science. 348 (6239): 1118–1122. doi: 10.1126/science.1262024 . ISSN   0036-8075.
  11. ↑ "Superlubricity-near zero friction from nanodiamonds | Anirudha Sumant | TEDxNaperville". YouTube. 2018-11-30. Retrieved 2022-04-01.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.