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de Brito ACF, Sousa SMD, Morais HLOD, Costa PHMD, Medrado NV, Prado MDC, Barcelos ID, Alvarenga ÉCD, Neves BRA, Barboza APM, Manhabosco TM. Cutting-edge collagen biocomposite reinforced with 2D nano-talc for bone tissue engineering. NANOMEDICINE : NANOTECHNOLOGY, BIOLOGY, AND MEDICINE 2024; 60:102756. [PMID: 38851439 DOI: 10.1016/j.nano.2024.102756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 03/23/2024] [Accepted: 05/13/2024] [Indexed: 06/10/2024]
Abstract
The advancement of nanobiocomposites reinforced with 2D nano-materials plays a pivotal role in enhancing bone tissue engineering. In this study, we introduce a nanobiocomposite that reinforces bovine collagen with 2D nano-talc, a recently exfoliated nano-mineral. These nanobiocomposites were prepared by blending collagen with varying concentrations of 2D nano-talc, encompassing mono- and few-layers talc from soapstone nanomaterial. Extensive characterization techniques including AFM, XPS, nano-FTIR, s-SNOM nanoimaging, Force Spectroscopy, and PeakForce QNM® were employed. The incorporation of 2D nano-talc significantly enhanced the mechanical properties of the nanobiocomposites, resulting in increased stiffness compared to pristine collagen. In vitro studies supported the growth and proliferation of osteoblasts onto 2D nano-talc-reinforced nanobiocomposites, as well as showed the highest mineralization potential. These findings highlight the substantial potential of the developed nanobiocomposite as a scaffold material for bone tissue engineering applications.
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Affiliation(s)
- Ana Carolina Ferreira de Brito
- Physics Department, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, MG, Brazil; Physics Department, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil; Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil.
| | | | | | | | - Nathanael Vieira Medrado
- Departamento de Bioquímica e Imunologia, Laboratório de Sinalização Celular e Nanobiotecnologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil
| | - Mariana de Castro Prado
- Physics Department, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, MG, Brazil
| | - Ingrid David Barcelos
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Érika Costa de Alvarenga
- Departamento de Ciências Naturais, Universidade Federal de São João Del Rei, 36301-160 São João Del Rei, MG, Brazil; Departamento de Bioquímica e Imunologia, Laboratório de Sinalização Celular e Nanobiotecnologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil
| | - Bernardo Ruegger Almeida Neves
- Physics Department, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil
| | - Ana Paula Moreira Barboza
- Physics Department, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, MG, Brazil
| | - Taíse Matte Manhabosco
- Physics Department, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, MG, Brazil
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Wang L, Sun YN, Wei XD, Yin M, Chen Y, Miura H, Suzuki K, Wang C. The uniaxial zero thermal expansion and zero linear compressibility in distorted Prussian blue analogue RbCuCo(CN) 6. Phys Chem Chem Phys 2023. [PMID: 38047321 DOI: 10.1039/d3cp04563c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The uniaxial zero thermal expansion (ZTE) in distorted Prussian blue analogue (PBA) RbCuCo(CN)6 is reproduced by employing first-principles calculations, which agrees well with the experimental data. Also, the zero linear compressibility (ZLC) behavior in RbCuCo(CN)6 can be found. The special Jahn-Teller distortion introduced by Cu2+ in RbCuCo(CN)6 is noticed by investigating the change of the local structure with temperature and hydrostatic pressure. The lattice thermal conductivity (LTC) and phonon group velocity of RbCuCo(CN)6 are studied, where the LTC and phonon group velocity are significantly anisotropic. Especially, RbCuCo(CN)6 exhibits a quite low LTC, and its c-axis shows a characteristic of glasslike LTC at low temperatures. Our work facilitates a deep understanding of the coexistence mechanisms of uniaxial ZTE and ZLC properties in RbCuCo(CN)6.
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Affiliation(s)
- Lei Wang
- Department of Physics, Institute of Theoretical Physics, University of Science and Technology Beijing, Beijing 100083, China.
| | - Ya-Ning Sun
- Department of Physics, Institute of Theoretical Physics, University of Science and Technology Beijing, Beijing 100083, China.
| | - Xian-Deng Wei
- Department of Physics, Institute of Theoretical Physics, University of Science and Technology Beijing, Beijing 100083, China.
| | - Meng Yin
- Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Ying Chen
- Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Hideo Miura
- Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Ken Suzuki
- Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Cong Wang
- School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
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Arrighi A, Ullberg N, Derycke V, Grévin B. A simple KPFM-based approach for electrostatic- free topographic measurements: the case of MoS 2on SiO 2. NANOTECHNOLOGY 2023; 34:215705. [PMID: 36812541 DOI: 10.1088/1361-6528/acbe02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
A simple implementation of Kelvin probe force microscopy (KPFM) is reported that enables recording topographic images in the absence of any component of the electrostatic force (including the static term). Our approach is based on a close loop z-spectroscopy operated in data cube mode. Curves of the tip-sample distance as a function of time are recorded onto a 2D grid. A dedicated circuit holds the KPFM compensation bias and subsequently cut off the modulation voltage during well-defined time-windows within the spectroscopic acquisition. Topographic images are recalculated from the matrix of spectroscopic curves. This approach is applied to the case of transition metal dichalcogenides (TMD) monolayers grown by chemical vapour deposition on silicon oxide substrates. In addition, we check to what extent a proper stacking height estimation can also be performed by recording series of images for decreasing values of the bias modulation amplitude. The outputs of both approaches are shown to be fully consistent. The results exemplify how in the operating conditions of non-contact AFM under ultra-high vacuum (nc-AFM), the stacking height values can dramatically be overestimated due to variations in the tip-surface capacitive gradient, even though the KPFM controller nullifies the potential difference. We show that the number of atomic layers of a TMD can be safely assessed, only if the KPFM measurement is performed with a modulated bias amplitude reduced at its strict minimum or, even better, without any modulated bias. Last, the spectroscopic data reveal that certain kind of defects can have a counterintuitive impact on the electrostatic landscape, resulting in an apparent decrease of the measured stacking height by conventional nc-AFM/KPFM compared to other sample areas. Hence, electrostatic free z-imaging proves to be a promising tool to assess the existence of defects in atomically thin TMD layers grown on oxides.
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Affiliation(s)
- Aloïs Arrighi
- Univ. Grenoble Alpes, CNRS, CEA, IRIG-SyMMES, F-38000 Grenoble, France
- lnstitut Néel, CNRS, Univ. Grenoble-Alpes, F-38042 Grenoble Cedex 09, France
| | - Nathan Ullberg
- Université Paris-Saclay, CEA, CNRS, NIMBE, LICSEN, F-91191 Gif-sur-Yvette, France
| | - Vincent Derycke
- Université Paris-Saclay, CEA, CNRS, NIMBE, LICSEN, F-91191 Gif-sur-Yvette, France
| | - Benjamin Grévin
- Univ. Grenoble Alpes, CNRS, CEA, IRIG-SyMMES, F-38000 Grenoble, France
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Wang L, Chen Y, Miura H, Suzuki K, Wang C. Penta-graphene and phagraphene: thermal expansion, linear compressibility, and Poisson's ratio. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:505301. [PMID: 36265479 DOI: 10.1088/1361-648x/ac9c3e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Nonplanar penta-graphene and planar phagraphene, which are connected by carbon pentagons and penta-hexa-hepta carbon rings, respectively, are two allotropes of graphene. Graphene as a star material in two-dimensional materials has been widely studied. However, the studies around penta-graphene and phagraphene are still insufficient. We are interested in both materials' response to temperature, hydrostatic pressure, and stress. In this work, the thermal expansion, linear compressibility, and Poisson's ratio of penta-graphene and phagraphene have been investigated systematically. It is found that both materials can exhibit abnormal negative thermal expansion behavior, while their linear compressibility behavior is normal. The negative Poisson's ratio behavior only occurs in penta-graphene, which is consistent with other work. Through an analysis of the lattice vibrations and associated mode Grüneisen parameters, it is found that there are anomalies in the phonon spectra of both penta-graphene and phagraphene. It is noted that acoustic phonons contribute most to their respective anomalies, especially the transverse acoustic mode. The librational motion of the lowest-frequency optical phonon of both materials is identified and also associated with their novel properties. In general, the unique topological arrangement of carbon atoms can play a decisive role in determining the performances of penta-graphene and phagraphene.
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Affiliation(s)
- Lei Wang
- Department of Physics, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
| | - Ying Chen
- Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Hideo Miura
- Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Ken Suzuki
- Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Cong Wang
- School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
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Liu C, Lu P, Chen W, Zhao Y, Chen Y. Phonon transport in graphene based materials. Phys Chem Chem Phys 2021; 23:26030-26060. [PMID: 34515261 DOI: 10.1039/d1cp02328d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Graphene, due to its atomic layer structure, has the highest room temperature thermal conductivity k for all known materials. Thus, it is expected that graphene based materials are the best candidates for thermal management in next generation electronic devices. In this perspective, we first review the in-plane k of monolayer graphene and multilayer graphene obtained using experimental measurements, theoretical calculations and molecular dynamics (MD) simulations. Considering the importance of four-phonon scattering in graphene, we also compare the effects of three-phonon and four-phonon scattering on phonon transport in graphene. Then, we review phonon transport along the cross-plane direction of multilayer graphene and highlight that the cross-plane phonon mean free path is several hundreds of nanometers instead of a few nanometers as predicted using classical kinetic theory. Recently, hydrodynamic phonon transport has been observed experimentally in graphitic materials. The criteria for distinguishing the hydrodynamic from ballistic and diffusive regimes are discussed, from which we conclude that graphene based materials with a high Debye temperature and high anharmonicity (due to ZA modes) are excellent candidates to observe the hydrodynamic phonon transport. In the fourth part, we review how to actively control phonon transport in graphene. Graphene and graphite are often adopted as additives in thermal management materials such as polymer nanocomposites and thermal interface materials due to their high k. However, the enhancement of the composite's k is not so high as expected because of the large thermal resistance between graphene sheets as well as between the graphene sheet and matrix. In the fifth part, we discuss the interfacial thermal resistance and analyze its effect on the thermal conductivity of graphene based materials. In the sixth part, we give a brief introduction to the applications of graphene based materials in thermal management. Finally, we conclude our review with some perspectives for future research.
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Affiliation(s)
- Chenhan Liu
- Engineering Laboratory for Energy System Process Conversion & Emission Reduction Technology of Jiangsu Province, School of Energy and Mechanical Engineering, Nanjing Normal University, Nanjing, 210042, P. R. China. .,Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing, 211100, P. R. China.
| | - Ping Lu
- Engineering Laboratory for Energy System Process Conversion & Emission Reduction Technology of Jiangsu Province, School of Energy and Mechanical Engineering, Nanjing Normal University, Nanjing, 210042, P. R. China.
| | - Weiyu Chen
- College of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing, 210037, P. R. China
| | - Yunshan Zhao
- School of Physics and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Yunfei Chen
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing, 211100, P. R. China.
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Qin T, Wang Z, Wang Y, Besenbacher F, Otyepka M, Dong M. Recent Progress in Emerging Two-Dimensional Transition Metal Carbides. NANO-MICRO LETTERS 2021; 13:183. [PMID: 34417663 PMCID: PMC8379312 DOI: 10.1007/s40820-021-00710-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 07/25/2021] [Indexed: 05/17/2023]
Abstract
As a new member in two-dimensional materials family, transition metal carbides (TMCs) have many excellent properties, such as chemical stability, in-plane anisotropy, high conductivity and flexibility, and remarkable energy conversation efficiency, which predispose them for promising applications as transparent electrode, flexible electronics, broadband photodetectors and battery electrodes. However, up to now, their device applications are in the early stage, especially because their controllable synthesis is still a great challenge. This review systematically summarized the state-of-the-art research in this rapidly developing field with particular focus on structure, property, synthesis and applicability of TMCs. Finally, the current challenges and future perspectives are outlined for the application of 2D TMCs.
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Affiliation(s)
- Tianchen Qin
- College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, People's Republic of China
| | - Zegao Wang
- College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, People's Republic of China.
| | - Yuqing Wang
- Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus, Denmark
| | | | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, 77146, Olomouc, Czech Republic
| | - Mingdong Dong
- Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus, Denmark.
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Ben J, Liu X, Wang C, Zhang Y, Shi Z, Jia Y, Zhang S, Zhang H, Yu W, Li D, Sun X. 2D III-Nitride Materials: Properties, Growth, and Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006761. [PMID: 34050555 DOI: 10.1002/adma.202006761] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/31/2020] [Indexed: 06/12/2023]
Abstract
2D III-nitride materials have been receiving considerable attention recently due to their excellent physicochemical properties, such as high stability, wide and tunable bandgap, and magnetism. Therefore, 2D III-nitride materials can be applied in various fields, such as electronic and photoelectric devices, spin-based devices, and gas detectors. Although the developments of 2D h-BN materials have been successful, the fabrication of other 2D III-nitride materials, such as 2D h-AlN, h-GaN, and h-InN, are still far from satisfactory, which limits the practical applications of these materials. In this review, recent advances in the properties, growth methods, and potential applications of 2D III-nitride materials are summarized. The properties of the 2D III-nitride materials are mainly obtained by first-principles calculations because of the difficulties in the growth and characterizations of these materials. The discussion on the growth of 2D III-nitride materials is focused on 2D h-BN and h-AlN, as the developments of 2D h-GaN and h-InN are yet to be realized. Therefore, applications have been realized mostly based on the 2D h-BN materials; however, many potential applications are cited for the entire range of 2D III-nitride materials. Finally, future research directions and prospects in this field are also discussed.
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Affiliation(s)
- Jianwei Ben
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China
| | - Xinke Liu
- College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Cong Wang
- Collaborative Innovation Center for Optoelectronic Science and Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Yupeng Zhang
- Collaborative Innovation Center for Optoelectronic Science and Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Zhiming Shi
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China
| | - Yuping Jia
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China
| | - Shanli Zhang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China
| | - Han Zhang
- Collaborative Innovation Center for Optoelectronic Science and Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Wenjie Yu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Dabing Li
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China
| | - Xiaojuan Sun
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China
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Cao P, Wu J. Self-Assembly of MoS 2 Monolayer Sheets by Desulfurization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:4971-4983. [PMID: 33858139 DOI: 10.1021/acs.langmuir.1c00369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Self-assembled structures of two-dimensional (2D) materials exhibit novel physical properties distinct from those of their parent materials. Herein, the critical role of desulfurization on the self-assembled structural morphologies of molybdenum disulfide (MoS2) monolayer sheets is explored using molecular dynamics (MD) simulations. MD results show that there are differences in the atomic energetics of MoS2 monolayer sheets with different desulfurization contents. Both free-standing and substrate-hosted MoS2 monolayer sheets show diversity in structural morphologies, for example, flat plane structures, wrinkles, nanotubes, and folds, depending on the desulfurization contents, planar dimensions, and ratios of length to width of MoS2 sheets. Particularly, at the critical desulfurization content, they can roll up into nanotubes, which is in good agreement with previous experimental observations. Importantly, these observed differences in the molecular structural morphologies between free-standing and substrate-hosted MoS2 monolayer sheets can be attributed to interatomic interactions and interlayer van der Waals interactions. Furthermore, MD results have demonstrated that the surface-driven stability of MoS2 structures can be indicated by the desulfurization contents on one surface of MoS2 monolayer sheets, and the self-assembly of MoS2 monolayer sheets by desulfurization can emerge to adjust their surface-driven stability. The study provides important atomic insights into tuning the self-assembling structural morphologies of 2D materials through defect engineering in the future science and engineering applications.
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Affiliation(s)
- Pinqiang Cao
- School of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan 430081, P. R. China
- Department of Physics, Research Institute for Biomimetics and Soft Matter, Jiujiang Research Institute, Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University, Xiamen 361005, P. R. China
| | - Jianyang Wu
- Department of Physics, Research Institute for Biomimetics and Soft Matter, Jiujiang Research Institute, Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University, Xiamen 361005, P. R. China
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Fan N, Guo J, Jing G, Liu C, Wang Q, Wu G, Jiang H, Peng B. A hillock-like phenomenon with low friction and adhesion on a graphene surface induced by relative sliding at the interface of graphene and the SiO 2 substrate using an AFM tip. NANOSCALE ADVANCES 2020; 2:2548-2557. [PMID: 36133360 PMCID: PMC9418518 DOI: 10.1039/c9na00660e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 03/29/2020] [Indexed: 06/16/2023]
Abstract
Graphene demonstrates high potential as an atomically thin solid lubricant for sliding interfaces in industry. However, graphene as a coating material does not always exhibit strong adhesion to any substrates. When the adhesion of graphene to its substrate weakens, it remains unknown whether relative sliding at the interface exists and how the tribological properties of the graphene coating changes. In this work, we first designed a method to weaken the adhesion between graphene and its SiO2 substrate. Then the graphene with weakened adhesion to its substrate was rubbed using an AFM tip, where we found a novel phenomenon: the monolayer graphene not only no longer protected the SiO2 substrate from deformation and damage, but also prompted the formation of hillock-like structures with heights of approximately tens of nanometers. Moreover, the surface of the hillock-like structure exhibited very low adhesion and a continuously decreasing friction force versus sliding time. Comparing the hillock-like structure on the bare SiO2 surface and the proposed force model, we demonstrated that the emergence of the hillock-like structure (with very low adhesion and continuously decreasing friction) was ascribed to the relative sliding at the graphene/substrate interface caused by the mechanical shear of the AFM tip. Our findings reveal a potential failure of the graphene coating when the adhesion strength between graphene and its substrate is damaged or weakened and provide a possibility for in situ fabrication of a low friction and adhesion micro/nanostructure on a SiO2/graphene surface.
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Affiliation(s)
- Na Fan
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China Chengdu 611731 China
| | - Jian Guo
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China Chengdu 611731 China
- School of Mechanical Engineering, University of South China Hengyang 421001 China
| | - Guangyin Jing
- National Key Laboratory and Incubation Base of Photoelectric Technology and Functional Materials, School of Physics, Northwest University Xi'an 710069 China
| | - Cheng Liu
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China Chengdu 611731 China
| | - Qun Wang
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China Chengdu 611731 China
| | - Guiyong Wu
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China Chengdu 611731 China
| | - Hai Jiang
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China Chengdu 611731 China
| | - Bei Peng
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China Chengdu 611731 China
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10
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Batista RJC, Dias RF, Barboza APM, de Oliveira AB, Manhabosco TM, Gomes-Silva TR, Matos MJS, Gadelha AC, Rabelo C, Cançado LGL, Jorio A, Chacham H, Neves BRA. Nanomechanics of few-layer materials: do individual layers slide upon folding? BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1801-1808. [PMID: 33335824 PMCID: PMC7722626 DOI: 10.3762/bjnano.11.162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/16/2020] [Indexed: 05/17/2023]
Abstract
Folds naturally appear on nanometrically thin materials, also called "2D materials", after exfoliation, eventually creating folded edges across the resulting flakes. We investigate the adhesion and flexural properties of single-layered and multilayered 2D materials upon folding in the present work. This is accomplished by measuring and modeling mechanical properties of folded edges, which allows for the experimental determination of the bending stiffness (κ) of multilayered 2D materials as a function of the number of layers (n). In the case of talc, we obtain κ ∝ n 3 for n ≥ 5, indicating no interlayer sliding upon folding, at least in this thickness range. In contrast, tip-enhanced Raman spectroscopy measurements on edges in folded graphene flakes, 14 layers thick, show no significant strain. This indicates that layers in graphene flakes, up to 5 nm thick, can still slip to relieve stress, showing the richness of the effect in 2D systems. The obtained interlayer adhesion energy for graphene (0.25 N/m) and talc (0.62 N/m) is in good agreement with recent experimental results and theoretical predictions. The obtained value for the adhesion energy of graphene on a silicon substrate is also in agreement with previous results.
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Affiliation(s)
- Ronaldo J C Batista
- Departamento de Física, Universidade Federal de Ouro Preto, 35400-000, Ouro Preto, MG, Brazil
| | - Rafael F Dias
- Departamento de Física, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil
| | - Ana P M Barboza
- Departamento de Física, Universidade Federal de Ouro Preto, 35400-000, Ouro Preto, MG, Brazil
| | - Alan B de Oliveira
- Departamento de Física, Universidade Federal de Ouro Preto, 35400-000, Ouro Preto, MG, Brazil
| | - Taise M Manhabosco
- Departamento de Física, Universidade Federal de Ouro Preto, 35400-000, Ouro Preto, MG, Brazil
| | - Thiago R Gomes-Silva
- Departamento de Física, Universidade Federal de Ouro Preto, 35400-000, Ouro Preto, MG, Brazil
| | - Matheus J S Matos
- Departamento de Física, Universidade Federal de Ouro Preto, 35400-000, Ouro Preto, MG, Brazil
| | - Andreij C Gadelha
- Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, MG, Brazil
| | - Cassiano Rabelo
- Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, MG, Brazil
| | - Luiz G L Cançado
- Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, MG, Brazil
| | - Ado Jorio
- Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, MG, Brazil
| | - Hélio Chacham
- Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, MG, Brazil
| | - Bernardo R A Neves
- Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, MG, Brazil
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Wang L, Wang C, Chen Y. Black phosphorene exhibiting negative thermal expansion and negative linear compressibility. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:465003. [PMID: 31357186 DOI: 10.1088/1361-648x/ab3673] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Positive expansion on heating, and positive contraction on hydrostatic compression are our general understanding. Actually, the abnormal negative thermal expansion (NTE) or negative linear compressibility (NLC) behavior is permissible, but exists in very few materials. Interestingly, we find that the NTE and NLC behaviors can coexist in the low-dimensional black phosphorene using first-principles calculations. In the temperature-field, the volume-NTE of black phosphorene can be exhibited below about 200 K, while the axial-NTE exists in the whole studied temperature range. In the hydrostatic pressure-field, the NLC behavior can occur along a zigzag direction or armchair direction in different pressure ranges. The phonon abnormality in black phosphorene is detected. It is found that acoustic phonons, especially the lowest-frequency TA z mode, play a very important role. The re-entrant honeycomb network in black phosphorene, as the specific topology, will facilitate the occurrence of NTE and NLC behaviors. This work can provide some foundations and clues for exploring the abnormal properties in other 2D materials.
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Affiliation(s)
- Lei Wang
- Department of Physics, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
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12
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Ren Z, Yang Y, Lin Y, Guo Z. Tribological Properties of Molybdenum Disulfide and Helical Carbon Nanotube Modified Epoxy Resin. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E903. [PMID: 30889884 PMCID: PMC6471027 DOI: 10.3390/ma12060903] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/08/2019] [Accepted: 03/14/2019] [Indexed: 12/04/2022]
Abstract
In this study, epoxy resin (EP) composites were prepared by using molybdenum disulfide (MoS₂) and helical carbon nanotubes (H-CNTs) as the antifriction and reinforcing phases, respectively. The effects of MoS₂ and H-CNTs on the friction coefficient, wear amount, hardness, and elastic modulus of the composites were investigated. The tribological properties of the composites were tested using the UMT-3MT friction testing machine, non-contact three-dimensional surface profilometers, and nanoindenters. The analytical results showed that the friction coefficient of the composites initially decreased and then increased with the increase in the MoS₂ content. The friction coefficient was the smallest when the MoS₂ content in the EP was 6%, and the wear amount increased gradually. With the increasing content of H-CNTs, the friction coefficient of the composite material did not change significantly, although the wear amount decreased gradually. When the MoS₂ and H-CNTs contents were 6% and 4%, respectively, the composite exhibited the minimum friction coefficient and a small amount of wear. Moreover, the addition of H-CNTs significantly enhanced the hardness and elastic modulus of the composites, which could be applied as materials in high-temperature and high-pressure environments where lubricants and greases do not work.
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Affiliation(s)
- Zhiying Ren
- College of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350116, China.
| | - Yu Yang
- College of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350116, China.
| | - Youxi Lin
- College of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350116, China.
| | - Zhiguang Guo
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
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13
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Huang Y, Liu L, Yang J, Chen Y. Nanotribological Properties of ALD-Made Ultrathin MoS 2 Influenced by Film Thickness and Scanning Velocity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:3651-3657. [PMID: 30777760 DOI: 10.1021/acs.langmuir.8b03970] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Solid lubricating films are usually applied to reduce friction and adhesion of micro-/nano-electromechanical systems (MEMS/NEMS). Due to the special structure, MoS2 is endowed with excellent lubricity. Layer-controlled ultrathin MoS2 films with strong interactions to the underlying substrates were prepared by atomic layer deposition (ALD) using MoCl5 and H2S and characterized by various measures. Nanotribological properties of the MoS2 films with different thicknesses were observed by an atomic force microscope tip under various loads. In the initial stage of ALD, bigger roughness induced by discontinuous nanoparticles can increase friction. However, when the number of ALD cycles is more than 3, the friction force can be effectively reduced by about 40-55% because of interlayer sliding and lower adhesion. Finally, friction properties against sliding velocities of the MoS2 films were also observed. The ultrathin MoS2 film obtained by ALD exhibits a huge application value as reducing friction surface in MEMS/NEMS.
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Affiliation(s)
- Yazhou Huang
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering , Southeast University , Nanjing 211189 , People's Republic of China
- Industrial Center , Nanjing Institute of Technology , Nanjing 211167 , People's Republic of China
| | - Lei Liu
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering , Southeast University , Nanjing 211189 , People's Republic of China
| | - Junjie Yang
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering , Southeast University , Nanjing 211189 , People's Republic of China
| | - Yunfei Chen
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering , Southeast University , Nanjing 211189 , People's Republic of China
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14
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Deng S, Che S, Debbarma R, Berry V. Strain in a single wrinkle on an MoS 2 flake for in-plane realignment of band structure for enhanced photo-response. NANOSCALE 2019; 11:504-511. [PMID: 30543229 DOI: 10.1039/c8nr05884a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Since 2D transition metal dichalcogenides (TMDs) exhibit strain-tunable bandgaps, locally confining strain can allow lateral manipulation of their band structure, in-plane carrier transport and optical transitions. Herein, we show that a single wrinkle (width = 10 nm-10 μm) on an MoS2 flake can induce confined uniaxial strain to reduce the local bandgap (40-60 meV per % deformation), producing a microscopic exciton funnel with an enhancement in photocurrent over flat MoS2 devices. This study also shows that wrinkles can spatially reconfigure the distribution of dopants and enhance the light absorption in the MoS2 layer via Fabry-Perot interference in its nanocavity. In the field-effect transistor studies on the MoS2 flat-wrinkle-flat device-structure, a higher carrier mobility and an improvement in the on/off ratio were exhibited in the devices with a single wrinkle. This phenomenon is attributed to the built-in potential induced by the bandgap reduction at the wrinkle site and the change in doping of the suspended wrinkle. The wrinkle-induced tunability of the local bandgap and manipulation of the spatial transport barriers, and the enhanced light absorption can enable development of next-generation electronic and optoelectronic devices guided by in-plane deformation of 2D nanomaterials.
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Affiliation(s)
- Shikai Deng
- Department of Chemical Engineering, University of Illinois at Chicago, 810 South Clinton Street, Chicago, Illinois 60607, USA.
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15
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Khac BCT, DelRio FW, Chung KH. Interfacial Strength and Surface Damage Characteristics of Atomically Thin h-BN, MoS 2, and Graphene. ACS APPLIED MATERIALS & INTERFACES 2018; 10:9164-9177. [PMID: 29464947 PMCID: PMC5969908 DOI: 10.1021/acsami.8b00001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Surface damage characteristics of single- and multilayer hexagonal boron nitride (h-BN), molybdenum disulfide (MoS2), and graphene films were systematically investigated via atomic force microscopy (AFM)-based progressive-force and constant-force scratch tests and Raman spectroscopy. The film-to-substrate interfacial strengths of these atomically thin films were assessed based on their critical forces (i.e., the normal force where the atomically thin film was delaminated from the underlying substrate), as determined from progressive-force scratch tests. The evolution of surface damage with respect to normal force was further investigated using constant-force tests. The results showed that single-layer h-BN, MoS2, and graphene strongly adhere to the SiO2 substrate, which significantly improves its tribological performance. Moreover, defect formation induced by scratch testing was found to affect the topography and friction force differently prior to failure, which points to distinct surface damage characteristics. Interestingly, the residual strains at scratched areas suggest that the scratch test-induced in-plane compressive strains were dominant over tensile strains, thereby leading to buckling in front of the scratching tip and eventually failure at sufficient strains. These trends represent the general failure mechanisms of atomically thin materials because of a scratch test. As the number of layers increased, the tribological performances of atomically thin h-BN, MoS2, and graphene were found to significantly improve because of an increase in the interfacial strengths and a decrease in the surface damage and friction force. In all, the findings on the distinctive surface damage characteristics and general failure mechanisms are useful for the design of reliable, protective and solid-lubricant coating layers based on these materials for nanoscale devices.
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Affiliation(s)
- Bien-Cuong Tran Khac
- School of Mechanical Engineering, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Frank W. DelRio
- Applied Chemicals and Materials Division, Material Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Koo-Hyun Chung
- School of Mechanical Engineering, University of Ulsan, Ulsan 44610, Republic of Korea
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16
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Chacham H, Barboza APM, de Oliveira AB, de Oliveira CK, Batista RJC, Neves BRA. Universal deformation pathways and flexural hardening of nanoscale 2D-material standing folds. NANOTECHNOLOGY 2018; 29:095704. [PMID: 29300171 DOI: 10.1088/1361-6528/aaa51e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In the present work, we use atomic force microscopy nanomanipulation of 2D-material standing folds to investigate their mechanical deformation. Using graphene, h-BN and talc nanoscale wrinkles as testbeds, universal force-strain pathways are clearly uncovered and well-accounted for by an analytical model. Such universality further enables the investigation of each fold bending stiffness κ as a function of its characteristic height h 0. We observe a more than tenfold increase of κ as h 0 increases in the 10-100 nm range, with power-law behaviors of κ versus h 0 with exponents larger than unity for the three materials. This implies anomalous scaling of the mechanical responses of nano-objects made from these materials.
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Affiliation(s)
- Helio Chacham
- Dept. of Physics, Universidade Federal de Minas Gerais, 30123-970, Belo Horizonte, Minas Gerais, Brazil
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17
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Cui L, Shi S, Wei G, Du X. Shear deformation-induced anisotropic thermal conductivity of graphene. Phys Chem Chem Phys 2018; 20:951-957. [DOI: 10.1039/c7cp06415b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Investigation of anisotropic thermal transport in graphene wrinkles considering the effect of both shear strain and strain-induced wrinkling configurations.
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Affiliation(s)
- Liu Cui
- Key Laboratory of Condition Monitoring and Control for Power Plant Equipment
- Ministry of Education
- North China Electric Power University
- Changping
- China
| | - Sanqiang Shi
- Department of Mechanical Engineering
- The Hong Kong Polytechnic University
- Hung Hom
- Kowloon
- China
| | - Gaosheng Wei
- Key Laboratory of Condition Monitoring and Control for Power Plant Equipment
- Ministry of Education
- North China Electric Power University
- Changping
- China
| | - Xiaoze Du
- Key Laboratory of Condition Monitoring and Control for Power Plant Equipment
- Ministry of Education
- North China Electric Power University
- Changping
- China
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18
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Jiang P, Qian X, Gu X, Yang R. Probing Anisotropic Thermal Conductivity of Transition Metal Dichalcogenides MX 2 (M = Mo, W and X = S, Se) using Time-Domain Thermoreflectance. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29. [PMID: 28727182 DOI: 10.1002/adma.201701068] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/15/2017] [Indexed: 05/13/2023]
Abstract
Transition metal dichalcogenides (TMDs) are a group of layered 2D semiconductors that have shown many intriguing electrical and optical properties. However, the thermal transport properties in TMDs are not well understood due to the challenges in characterizing anisotropic thermal conductivity. Here, a variable-spot-size time-domain thermoreflectance approach is developed to simultaneously measure both the in-plane and the through-plane thermal conductivity of four kinds of layered TMDs (MoS2 , WS2 , MoSe2 , and WSe2 ) over a wide temperature range, 80-300 K. Interestingly, it is found that both the through-plane thermal conductivity and the Al/TMD interface conductance depend on the modulation frequency of the pump beam for all these four compounds. The frequency-dependent thermal properties are attributed to the nonequilibrium thermal resistance between the different groups of phonons in the substrate. A two-channel thermal model is used to analyze the nonequilibrium phonon transport and to derive the intrinsic thermal conductivity at the thermal equilibrium limit. The measurements of the thermal conductivities of bulk TMDs serve as an important benchmark for understanding the thermal conductivity of single- and few-layer TMDs.
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Affiliation(s)
- Puqing Jiang
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Xin Qian
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Xiaokun Gu
- Institute of Engineering Thermophysics, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ronggui Yang
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
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19
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20
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Ouyang Q, Zhang K, Chen W, Zhou F, Ji W. Nonlinear absorption and nonlinear refraction in a chemical vapor deposition-grown, ultrathin hexagonal boron nitride film. OPTICS LETTERS 2016; 41:1368-1371. [PMID: 27192238 DOI: 10.1364/ol.41.001368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An ultrathin hexagonal boron nitride film is synthesized by a method of chemical vapor deposition. Irradiated by femtosecond laser pulses in the visible spectrum of 400-800 nm, it exhibits multiphoton absorption and positive nonlinear refraction properties. The two-photon and three-photon absorption coefficients are of the order of 10-5 cm W-1 and 10-14 cm3 W-2, respectively. The nonlinear refraction coefficient is as large as ∼10-8 cm2 W-1. These nonlinear coefficients lead to figures of merit that meet the material requirements for all-optical switching devices.
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21
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de Lima AL, Müssnich LAM, Manhabosco TM, Chacham H, Batista RJC, de Oliveira AB. Soliton instability and fold formation in laterally compressed graphene. NANOTECHNOLOGY 2015; 26:045707. [PMID: 25566691 DOI: 10.1088/0957-4484/26/4/045707] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We investigate-through simulations and analytical calculations-the consequences of uniaxial lateral compression applied to the upper layer of multilayer graphene. The simulations of compressed graphene show that strains larger than 2.8% induce soliton-like deformations that further develop into large, mobile folds. Such folds were indeed experimentally observed in graphene and other solid lubricants two-dimensional (2D) materials. Interestingly, in the soliton-fold regime, the shear stress decreases with the strain s, initially as s(-2/3) and rapidly going to zero. Such instability is consistent with the recently observed negative dynamic compressibility of 2D materials. We also predict that the curvatures of the soliton-folds are given by r(c) = δ√(β/2α) where 1 ≤ δ ≤ 2 and β and α are respectively related to the layer bending modulus and to the interlayer binding energy of the material. This finding might allow experimental estimates of the β/α ratio of 2D materials from fold morphology.
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Affiliation(s)
- Amauri Libério de Lima
- Departamento de Física, Universidade Federal de Ouro Preto, Ouro Preto, MG, 35400-000, Brazil
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22
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Samanta S, Singh S, Sahoo RR. Simultaneous chemical reduction and surface functionalization of graphene oxide for efficient lubrication of steel–steel contact. RSC Adv 2015. [DOI: 10.1039/c5ra10696f] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A facile approach for modulating the friction and wear by functionalized graphene oxide nanolubricants for metallic sliding contact is discussed.
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Affiliation(s)
- Suprakash Samanta
- Surface Engineering & Tribology Division
- CSIR-Central Mechanical Engineering Research Institute
- Durgapur 713209
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Santosh Singh
- Surface Engineering & Tribology Division
- CSIR-Central Mechanical Engineering Research Institute
- Durgapur 713209
- India
| | - Rashmi. R. Sahoo
- Surface Engineering & Tribology Division
- CSIR-Central Mechanical Engineering Research Institute
- Durgapur 713209
- India
- Academy of Scientific and Innovative Research (AcSIR)
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Ma TY, Tang Y, Dai S, Qiao SZ. Proton-functionalized two-dimensional graphitic carbon nitride nanosheet: an excellent metal-/label-free biosensing platform. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2014; 10:2382-9. [PMID: 24596304 DOI: 10.1002/smll.201303827] [Citation(s) in RCA: 225] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 01/18/2014] [Indexed: 05/08/2023]
Abstract
Ultrathin graphitic carbon nitride (g-C3N4) nanosheets, due to their interesting two-dimensional graphene-like structure and unique physicochemical properties, have attracted great research attention recently. Here, a new approach is developed to prepare, for the first time, proton-functionalized ultrathin g-C3N4 nanosheets by sonication-exfoliation of bulk g-C3N4 under an acid condition. This method not only reduces the exfoliation time from more than 10 h to 2 h, but also endows the nanosheets with positive charges. Besides retaining the properties of g-C3N4, the obtained nanosheets with the thickness of 2-4 nm (i.e., 6-12 atomic monolayers) also exhibit large specific surface area of 305 m(2) g(-1), enhanced fluorescence intensity, and excellent water dispersion stability due to their surface protonation and ultrathin morphology. The well-dispersed protonated g-C3N4 nanosheets are able to interact with negatively charged heparin, which results in the quenching of g-C3N4 fluorescence. A highly sensitive and highly selective heparin sensing platform based on protonated g-C3N4 nanosheets is established. This metal-free and fluorophore label-free system can reach the lowest heparin detection limit of 18 ng mL(-1).
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Affiliation(s)
- Tian Yi Ma
- School of Chemical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia
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Morandi V, Ortolani L, Migliori A, Degli Esposti Boschi C, Cadelano E, Colombo L. Folds and buckles at the nanoscale: experimental and theoretical investigation of the bending properties of graphene membranes. Top Curr Chem (Cham) 2014; 348:205-236. [PMID: 23780412 DOI: 10.1007/128_2013_451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The elastic properties of graphene crystals have been extensively investigated, revealing unique properties in the linear and nonlinear regimes, when the membranes are under either stretching or bending loading conditions. Nevertheless less knowledge has been developed so far on folded graphene membranes and ribbons. It has been recently suggested that fold-induced curvatures, without in-plane strain, can affect the local chemical reactivity, the mechanical properties, and the electron transfer in graphene membranes. This intriguing perspective envisages a materials-by-design approach through the engineering of folding and bending to develop enhanced nano-resonators or nano-electro-mechanical devices. Here we present a novel methodology to investigate the mechanical properties of folded and wrinkled graphene crystals, combining transmission electron microscopy mapping of 3D curvatures and theoretical modeling based on continuum elasticity theory and tight-binding atomistic simulations.
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Abstract
We studied the thermophoretic motion of wrinkles formed in substrate-supported graphene sheets by nonequilibrium molecular dynamics simulations. We found that a single wrinkle moves along applied temperature gradient with a constant acceleration that is linearly proportional to temperature deviation between the heating and cooling sides of the graphene sheet. Like a solitary wave, the atoms of the single wrinkle drift upwards and downwards, which prompts the wrinkle to move forwards. The driving force for such thermophoretic movement can be mainly attributed to a lower free energy of the wrinkle back root when it is transformed from the front root. We establish a motion equation to describe the soliton-like thermophoresis of a single graphene wrinkle based on the Korteweg-de Vries equation. Similar motions are also observed for wrinkles formed in a Cu-supported graphene sheet. These findings provide an energy conversion mechanism by using graphene wrinkle thermophoresis.
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Affiliation(s)
- Yufeng Guo
- State Key Laboratory of Mechanics and Control of Mechanical Structures, Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
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26
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Lin Y, Connell JW. Advances in 2D boron nitride nanostructures: nanosheets, nanoribbons, nanomeshes, and hybrids with graphene. NANOSCALE 2012; 4:6908-39. [PMID: 23023445 DOI: 10.1039/c2nr32201c] [Citation(s) in RCA: 360] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The recent surge in graphene research has stimulated interest in the investigation of various 2-dimensional (2D) nanomaterials. Among these materials, the 2D boron nitride (BN) nanostructures are in a unique position. This is because they are the isoelectric analogs to graphene structures and share very similar structural characteristics and many physical properties except for the large band gap. The main forms of the 2D BN nanostructures include nanosheets (BNNSs), nanoribbons (BNNRs), and nanomeshes (BNNMs). BNNRs are essentially BNNSs with narrow widths in which the edge effects become significant; BNNMs are also variations of BNNSs, which are supported on certain metal substrates where strong interactions and the lattice mismatch between the substrate and the nanosheet result in periodic shallow regions on the nanosheet surface. Recently, the hybrids of 2D BN nanostructures with graphene, in the form of either in-plane hybrids or inter-plane heterolayers, have also drawn much attention. In particular, the BNNS-graphene heterolayer architectures are finding important electronic applications as BNNSs may serve as excellent dielectric substrates or separation layers for graphene electronic devices. In this article, we first discuss the structural basics, spectroscopic signatures, and physical properties of the 2D BN nanostructures. Then, various top-down and bottom-up preparation methodologies are reviewed in detail. Several sections are dedicated to the preparation of BNNRs, BNNMs, and BNNS-graphene hybrids, respectively. Following some more discussions on the applications of these unique materials, the article is concluded with a summary and perspectives of this exciting new field.
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Affiliation(s)
- Yi Lin
- National Institute of Aerospace, 100 Exploration way, Hampton, VA 23666, USA.
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