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Wang H, Zhang H, Zhang X, Cao T, Shi J, Fan X. Structural superlubricity at the interface of penta-BN 2. Phys Chem Chem Phys 2024; 26:18871-18880. [PMID: 38946706 DOI: 10.1039/d4cp00619d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Two-dimensional (2D) materials have been widely used as lubricants due to their weak interlayer interaction and low shear resistance for interlayer sliding. Composed entirely of five-membered rings, penta-BN2 monolayer has excellent thermal and mechanical stability, higher hardness and a negative Poisson's ratio. In this work, we investigate the frictional properties at both the commensurate and incommensurate contacting interfaces of penta-BN2 by adopting the molecular dynamics (MD) simulation method. Our calculations demonstrate robust superlubricity at the incommensurate contacting interface of penta-BN2. The ultra-low friction is explained by the potential energy surface (PES) fluctuations, interlayer binding energy and out-of-plane motion amplitude of the sliding layer. In addition, our calculations show that the anisotropy of friction at the commensurate contacting interface is more obvious compared with that at the incommensurate contacting interface. Finally, the influences of the size of the Moiré pattern, normal force, temperature and sliding velocity on the friction are examined. Our results show that 2D penta-BN2 is a promising solid lubricant, enriching the family of 2D lubrication materials.
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Affiliation(s)
- Hao Wang
- State Key Laboratory of Solidification Processing, Center for Advanced Lubrication and Seal Materials, School of Material Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China.
| | - Hanyue Zhang
- Queen Mary University of London Engineering School, Northwestern Polytechnical University, 127 YouYi Western Road, Xi'an, Shaanxi, 710072, China
| | - Xinqi Zhang
- State Key Laboratory of Solidification Processing, Center for Advanced Lubrication and Seal Materials, School of Material Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China.
| | - Tengfei Cao
- State Key Laboratory of Solidification Processing, Center for Advanced Lubrication and Seal Materials, School of Material Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China.
| | - Junqi Shi
- State Key Laboratory of Solidification Processing, Center for Advanced Lubrication and Seal Materials, School of Material Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China.
| | - Xiaoli Fan
- State Key Laboratory of Solidification Processing, Center for Advanced Lubrication and Seal Materials, School of Material Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China.
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Sun Q, Liu W, Huang D, Huang X, Xu S, Wang J, Ye Z, Wang X, Wu S, Yue Y. Molecular dynamics study on thermal conductance between a nanotip and a substrate under vertical forces and horizontal sliding. Phys Chem Chem Phys 2023; 25:5510-5519. [PMID: 36723186 DOI: 10.1039/d2cp04655e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The heat transfer between a nanotip and its substrate is extremely complex but is a key factor in determining the measurement accuracy in tip-assisted nanomanufacturing and thermometry. In this work, the heat transfer from the nanotip to the substrate during sliding is investigated using molecular dynamics simulations. Interfacial interaction and bond formation are analyzed during the sliding process. The results show that the increase of vertical force would greatly improve the interface thermal conductance between the nanotip and the substrate. It is found that more bonds are formed and there are larger contact areas at the interface. In addition, we found that the thermal conductivity of the nanotip is another obstacle for heat transfer between the tip and substrate and it is greatly limited by the nanotip diameter near contact which is close to or even smaller than the phonon mean free path. Meanwhile, the dynamic formation and breakage of the covalent bonds during the sliding could gradually smoothen the tip apex and enhance the thermal transport at the interface. This work provides guidance for the thermal design of a nanotip-substrate system for nanoscale thermal transport measurements.
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Affiliation(s)
- Qiangsheng Sun
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Wenxiang Liu
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Dezhao Huang
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Xiaona Huang
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Shen Xu
- School of Mechanical and Automotive Engineering, Shanghai University of Engineering Science, Shanghai 201620, China
| | - Jianmei Wang
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Zhijiang Ye
- Department of Mechanical and Manufacturing Engineering, Miami University, Ohio 45056, USA
| | - Xiaosun Wang
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Shijing Wu
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Yanan Yue
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China. .,Department of Mechanical and Manufacturing Engineering, Miami University, Ohio 45056, USA
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Huang Z, Chen S, Lin Q, Ji Z, Gong P, Sun Z, Shen B. Microscopic Mechanisms Behind the High Friction and Failure Initiation of Graphene Wrinkles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:6776-6782. [PMID: 34032438 DOI: 10.1021/acs.langmuir.1c00862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Wrinkling occurs on the surfaces of large-area graphene ubiquitously. Despite that the wrinkled structures are found to degrade the lubricous property, the behind mechanisms remain less understood. Here, atomic force microscopy is adopted to characterize the friction and wear properties of graphene wrinkles (GWs) with different heights by nanoscratch tests. We verify the phenomena of high friction and reduced load-carrying capacity of wrinkles and report the observation of lubrication deterioration with increased heights. Using molecular dynamics simulations, we reveal that the contact quality at the interface is a dominant role in the friction evolution of wrinkles. The high friction of wrinkles is determined by the increased contact area and commensurability caused by the wrinkle deformation and topography changes. The wrinkle failure initiates near the root of the formed bilayer configuration due to the increased lateral stiffness and reduced atomic distance between the wrinkle layers. The increased interlocking effect results in a local shear stress of 91 GPa and induces the phase transitions of carbon atoms easily. As the wrinkle height decreases, the unstable local configuration weakens the interlocking effects and cannot fail even at a high load. This investigation sheds light on the microscopic frictional contact of GWs and provides guidance for tuning the tribological properties of graphene by controlling the wrinkle structures.
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Affiliation(s)
- Zhewei Huang
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Sulin Chen
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qiang Lin
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhe Ji
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Peng Gong
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Zhengzong Sun
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Bin Shen
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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Chatterjee A, Dubey DK, Sinha SK. Effect of Loading on the Adhesion and Frictional Characteristics of Top Layer Articular Cartilage Nanoscale Contact: A Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:46-62. [PMID: 33382944 DOI: 10.1021/acs.langmuir.0c02283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Articular cartilage is a water-lubricated naturally occurring biological interface imparting unique mechanical and ultralow frictional properties in bone joints. Although the material of cartilage, synovial fluid composition, and their lubricating modes and properties have been extensively investigated at various scales experimentally, there is still a lack of understanding of load bearing, adhesion, and friction mechanisms of the cartilage-cartilage interface from an atomistic perspective under heavy loads. In this study, the effect of loading on adhesion and frictional behavior in articular cartilage is investigated with a proposed atomistic model for top layer cartilage-cartilage contact in unhydrated conditions using molecular dynamics (MD) simulations. Pull-off tests reveal that cohesive interactions occur at the interface due to formation of heavily interpenetrated atomistic sites leading to stretching and localized pulling of fragments during sliding. Sliding tests show that friction is load- and direction-dependent with the coefficient of friction (COF) obtained in the range of 0.20-0.75 at the interface for sliding in parallel and perpendicular directions to the collagen axis. These values are in good agreement with earlier nanoscale experimental results reported for the top layer cartilage-cartilage interface. The COF reduces with an increase in load and tends to be higher for the parallel sliding case than for the perpendicular case owing to the presence of the constant number of H-bonds. Overall, this work contributes toward understanding sliding in unhydrated biointerfaces, which is the precursor of wear, and provides insights into implant research.
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Affiliation(s)
- Abhinava Chatterjee
- Mechanical Engineering Department, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Devendra K Dubey
- Mechanical Engineering Department, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Sujeet K Sinha
- Mechanical Engineering Department, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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Understanding the friction of atomically thin layered materials. Nat Commun 2020; 11:420. [PMID: 31964884 PMCID: PMC6972962 DOI: 10.1038/s41467-019-14239-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/17/2019] [Indexed: 11/08/2022] Open
Abstract
Friction is a ubiquitous phenomenon that greatly affects our everyday lives and is responsible for large amounts of energy loss in industrialised societies. Layered materials such as graphene have interesting frictional properties and are often used as (additives to) lubricants to reduce friction and protect against wear. Experimental Atomic Force Microscopy studies and detailed simulations have shown a number of intriguing effects such as frictional strengthening and dependence of friction on the number of layers covering a surface. Here, we propose a simple, fundamental, model for friction on thin sheets. We use our model to explain a variety of seemingly contradictory experimental as well as numerical results. This model can serve as a basis for understanding friction on thin sheets, and opens up new possibilities for ultimately controlling their friction and wear protection. Despite the fact that layered materials are often employed as lubricants, many of the underlying mechanisms are still controversial. Here the authors present a fundamental model for describing friction on atomically thin sheets that reveals the dynamics of strengthening and layer-number dependence of the friction.
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Shen B, Lin Q, Chen S, Huang Z, Ji Z, Cao A, Zhang Z. Double-Vacancy Controlled Friction on Graphene: The Enhancement of Atomic Pinning. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:12898-12907. [PMID: 31513424 DOI: 10.1021/acs.langmuir.9b01672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The vacancy-enhanced contact friction of graphene is mainly attributed to the vacancy-enhanced out-of-plane deformation flexibility of the graphene and the climbing of the tip out of the vacancy trap (which actually acts as a step edge). However, this mechanism does not apply for explaining the enhanced friction caused by small-sized vacancies that are unable to accommodate the tip, such as single vacancy and double vacancies, which also commonly exist in the graphene. In the present study, by performing a set of classic molecular dynamics simulations, we demonstrated that the double-vacancy defect in graphene substantially enhanced the contact friction when the tip slides over it and the pinning effect of the reconstructed lattice of the double-vacancy defect with atoms at the bottom of the tip dominated such an influence. The underlying mechanism of such an atomic pinning effect and the influence of the normal load, sliding direction, and the sliding velocity were unveiled by analyzing the obtained friction evolution and the atomic configuration and interaction between the tip and the graphene. We believe that the findings presented in this study complete the state-of-art understanding of the nanoscale friction behaviors of vacancy-defected graphene, which is essential for the implementation of their potential control.
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Liu Y, Song A, Xu Z, Zong R, Zhang J, Yang W, Wang R, Hu Y, Luo J, Ma T. Interlayer Friction and Superlubricity in Single-Crystalline Contact Enabled by Two-Dimensional Flake-Wrapped Atomic Force Microscope Tips. ACS NANO 2018; 12:7638-7646. [PMID: 30060665 DOI: 10.1021/acsnano.7b09083] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Interlayer friction between the atomic planes of 2D materials and heterostructures is a promising probe of the physics in their interlayer couplings and superlubricity. However, it is still challenging to measure the interlayer friction between well-defined 2D layers. We propose an approach of thermally assisted mechanical exfoliation and transfer to fabricate various 2D flake-wrapped atomic force microscopy (AFM) tips and to directly measure the interlayer friction between 2D flakes in single-crystalline contact. First, superlubricity between different 2D flakes and layered bulk materials is achieved with a friction coefficient as low as 10-4. The rotation angle dependence of superlubricity is observed for friction between graphite layers, whereas it is not observed between graphite and h-BN because of the incommensurate contact of the mismatched lattices. Second, the interlayer lateral force map between ReS2 layers is measured with atomic resolution, showing hexagonal patterns, as further verified by theoretical simulations. The tribological system constructed here offers an experimental platform to study interlayer couplings and friction between 2D flakes and layered bulk materials.
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Affiliation(s)
- Yanmin Liu
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084 , People's Republic of China
| | - Aisheng Song
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084 , People's Republic of China
| | - Zhi Xu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , People's Republic of China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100190 , People's Republic of China
| | - Ruilong Zong
- National Center of Electron Spectroscopy in Beijing , Beijing 100084 , People's Republic of China
| | - Jie Zhang
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084 , People's Republic of China
| | - Wenyan Yang
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084 , People's Republic of China
| | - Rong Wang
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084 , People's Republic of China
| | - Yuanzhong Hu
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084 , People's Republic of China
| | - Jianbin Luo
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084 , People's Republic of China
| | - TianBao Ma
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084 , People's Republic of China
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