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Yu H, Liu L, Yin R, Jayapurna I, Wang R, Xu T. Mapping Composition Evolution through Synthesis, Purification, and Depolymerization of Random Heteropolymers. J Am Chem Soc 2024; 146:6178-6188. [PMID: 38387070 PMCID: PMC10921401 DOI: 10.1021/jacs.3c13909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 02/24/2024]
Abstract
Random heteropolymers (RHPs) consisting of three or more comonomers have been routinely used to synthesize functional materials. While increasing the monomer variety diversifies the side-chain chemistry, this substantially expands the sequence space and leads to ensemble-level sequence heterogeneity. Most studies have relied on monomer composition and simulated sequences to design RHPs, but the questions remain unanswered regarding heterogeneities within each RHP ensemble and how closely these simulated sequences reflect the experimental outcomes. Here, we quantitatively mapped out the evolution of monomer compositions in four-monomer-based RHPs throughout a design-synthesis-purification-depolymerization process. By adopting a Jaacks method, we first determined 12 reactivity ratios directly from quaternary methacrylate RAFT copolymerization experiments to account for the influences of competitive monomer addition and the reversible activation/deactivation equilibria. The reliability of in silico analysis was affirmed by a quantitative agreement (<4% difference) between the simulated RHP compositions and the experimental results. Furthermore, we mapped out the conformation distribution within each ensemble in different solvents as a function of monomer chemistry, composition, and segmental characteristics via high-throughput computation based on self-consistent field theory (SCFT). These comprehensive studies confirmed monomer composition as a viable design parameter to engineer RHP-based functional materials as long as the reactivity ratios are accurately determined and the livingness of RHP synthesis is ensured.
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Affiliation(s)
- Hao Yu
- California
Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California 94720, United States
| | - Luofu Liu
- Department
of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Ruilin Yin
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Ivan Jayapurna
- Department
of Materials Science and Engineering, University
of California, Berkeley, Berkeley, California 94720, United States
| | - Rui Wang
- Department
of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
- Department
of Materials Science and Engineering, University
of California, Berkeley, Berkeley, California 94720, United States
| | - Ting Xu
- California
Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California 94720, United States
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
- Department
of Materials Science and Engineering, University
of California, Berkeley, Berkeley, California 94720, United States
- Departent
of Materials Science and Engineering, University
of California, Berkeley, Berkeley, California 94720, United States
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2
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Dong H, Moyle N, Wu H, Khripin CY, Hui CY, Jagota A. The transition from Elasto-Hydrodynamic to Mixed Regimes in Lubricated Friction of Soft Solid Surfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2211044. [PMID: 36779906 DOI: 10.1002/adma.202211044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/29/2023] [Indexed: 05/17/2023]
Abstract
Lubricated contacts in soft materials are common in various engineering and natural settings, such as tires, haptic applications, contact lenses, and the fabrication of soft electronic devices. Two major regimes are elasto-hydrodynamic lubrication (EHL), in which solid surfaces are fully separated by a fluid film, and mixed lubrication (ML), in which there is partial solid-to-solid contact. The transition between these regimes governs the minimum sliding friction achievable and is thus very important. Generally, the transition from EHL to ML regimes is believed to occur when the thickness of the lubricant layer is comparable with the amplitude of surface roughness. Here, it is reported that in lubricated sliding experiments on smooth, soft, poly(dimethylsiloxane) substrates, the transition can occur when the thickness of the liquid layer is much larger than the height of the asperities. Direct visualization of the "contact" region shows that the transition corresponds to the formation of wave-like surface wrinkles at the leading contact edge and associated instabilities at the trailing contact edge, which are believed to trigger the transition to the mixed regime. These results change the understanding of what governs the important EHL-ML transition in the lubricated sliding of soft solids.
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Affiliation(s)
- Hao Dong
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, 18015, USA
| | - Nichole Moyle
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, 18015, USA
| | - Haibin Wu
- Department of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, 14853, USA
| | | | - Chung-Yuen Hui
- Department of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - Anand Jagota
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, 18015, USA
- Department of Bioengineering, Lehigh University, Bethlehem, PA, 18015, USA
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3
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Qin Y, You Y, Jin G, Zhu W, Zhu Y, Wang Q, Lu X, Shi Y. Atomistic insight into the lubrication of glycerol aqueous solution: The role of the solid interface‐induced microstructure of fluid molecules. AIChE J 2022. [DOI: 10.1002/aic.17581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Yao Qin
- College of Chemical Engineering, State Key Laboratory of Materials‐Oriented Chemical Engineering Nanjing Tech University Nanjing People's Republic of China
| | - Yajing You
- College of Chemical Engineering, State Key Laboratory of Materials‐Oriented Chemical Engineering Nanjing Tech University Nanjing People's Republic of China
| | - Guangzheng Jin
- College of Chemical Engineering, State Key Laboratory of Materials‐Oriented Chemical Engineering Nanjing Tech University Nanjing People's Republic of China
| | - Wei Zhu
- College of Chemical Engineering, State Key Laboratory of Materials‐Oriented Chemical Engineering Nanjing Tech University Nanjing People's Republic of China
| | - Yudan Zhu
- College of Chemical Engineering, State Key Laboratory of Materials‐Oriented Chemical Engineering Nanjing Tech University Nanjing People's Republic of China
| | - Qiutian Wang
- College of Chemical Engineering, State Key Laboratory of Materials‐Oriented Chemical Engineering Nanjing Tech University Nanjing People's Republic of China
| | - Xiaohua Lu
- College of Chemical Engineering, State Key Laboratory of Materials‐Oriented Chemical Engineering Nanjing Tech University Nanjing People's Republic of China
| | - Yijun Shi
- Division of Machine Elements Luleå University of Technology Luleå Sweden
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4
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Ta TD, Tieu AK, Tran BH. Hydroxyl Influence on Adsorption and Lubrication of an Ultrathin Aqueous Triblock Copolymer Lubricant. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:1465-1479. [PMID: 33476165 DOI: 10.1021/acs.langmuir.0c02987] [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
This research aims to provide insights into the adsorption behaviors of two monomers of triblock copolymers (1,2-dimethoxyethane (1,2-DME) and 1,2-dimethoxypropane (1,2-DMP)) on a TiO2 surface in aqueous solution. A multiscale theoretical framework by means of the density functional theory (DFT), ab initio molecular dynamics (AIMD), and classical molecular dynamics (MD) simulations is established. The DFT calculation confirms that these molecules adsorb more energetically on a hydroxylated surface than pure oxide. There is a difference in adsorption behaviors between 1,2-DMP and 1,2-DME molecules due to the covalent bonding between carbons and oxygen of the hydroxylated TiO2 surface. The AIMD simulation reveals that the adsorption of both copolymers to the TiO2 surface is hindered by the presence of water with 1,2-DME exhibiting a weaker adsorption than 1,2-DMP. The presence of 1,2-DME on the TiO2 surface with water produced a smaller number of hydroxyl groups on the surface than 1,2-DMP. Moreover, the dissociative adsorption of water onto the rutile surface is the main cause for a chemical formation of terminating hydroxyl groups. The number of associated bonds is insignificant compared to the dissociated one since the dissociative adsorption is more favored than the associative one. MD simulation indicates that triblock copolymers adsorb stronger on the hydroxylated surface with a thinner adsorbed film thickness than that on the pure rutile. The presence of terminal hydroxyl groups on the rutile surface helps reducing the friction for aqueous 17R2 triblock copolymers, while it results in an increase of friction for normal copolymer L62.
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Affiliation(s)
- Thi D Ta
- School of Mechanical, Materials Mechatronic and Biomedical Engineering, Faculty of Engineering and Information Sciences (EIS), University of Wollongong, Northfield Avenue, Wollongong, New South Wales 2522, Australia
| | - A Kiet Tieu
- School of Mechanical, Materials Mechatronic and Biomedical Engineering, Faculty of Engineering and Information Sciences (EIS), University of Wollongong, Northfield Avenue, Wollongong, New South Wales 2522, Australia
| | - Bach H Tran
- School of Mechanical, Materials Mechatronic and Biomedical Engineering, Faculty of Engineering and Information Sciences (EIS), University of Wollongong, Northfield Avenue, Wollongong, New South Wales 2522, Australia
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Chouhan A, Kumari S, Sarkar TK, Rawat SS, Khatri OP. Graphene-Based Aqueous Lubricants: Dispersion Stability to the Enhancement of Tribological Properties. ACS APPLIED MATERIALS & INTERFACES 2020; 12:51785-51796. [PMID: 33151673 DOI: 10.1021/acsami.0c12122] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The present investigation demonstrates a green and scalable chemical approach to prepare aminoborate-functionalized reduced graphene oxide (rGO-AmB) for aqueous lubricants. The chemical, structural, crystalline, and morphological features of rGO-AmB are probed by XPS, FTIR, Raman, XRD, and HRTEM measurements. The spectroscopic analyses revealed the multiple interaction pathways between rGO and AmB. rGO-AmB exhibited long-term dispersion stability and improved the thermal conductivity of water by 68%. The thermal conductivity increased with increasing concentration of rGO-AmB and temperature. rGO-AmB as an additive to water (0.2%) enhanced the tribological properties of a steel tribopair under the boundary lubrication regime by the significant reduction in friction (70%) and wear (68%). The tribo-induced gradual deposition of an rGO-AmB-based thin film facilitated the interfacial sliding between the steel tribopair and protected it from the wear. The ultralow thickness, excellent dispersibility in water, high thermal conductivity, intrinsic low frictional properties, and good affinity toward the tribo-interfaces make rGO-AmB a potential candidate for aqueous lubricants.
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Affiliation(s)
- Ajay Chouhan
- CSIR-Indian Institute of Petroleum, Mohkampur, Dehradun 248005, India
- Academy of Scientific and Innovative Research, Ghaziabad 201002, India
| | - Sangita Kumari
- CSIR-Indian Institute of Petroleum, Mohkampur, Dehradun 248005, India
- Academy of Scientific and Innovative Research, Ghaziabad 201002, India
| | - Tarun K Sarkar
- CSIR-Indian Institute of Petroleum, Mohkampur, Dehradun 248005, India
| | - Sooraj S Rawat
- Department of Mechanical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Om P Khatri
- CSIR-Indian Institute of Petroleum, Mohkampur, Dehradun 248005, India
- Academy of Scientific and Innovative Research, Ghaziabad 201002, India
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6
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Wang Y, Yamada N, Xu J, Zhang J, Chen Q, Ootani Y, Higuchi Y, Ozawa N, Bouchet MIDB, Martin JM, Mori S, Adachi K, Kubo M. Triboemission of hydrocarbon molecules from diamond-like carbon friction interface induces atomic-scale wear. SCIENCE ADVANCES 2019; 5:eaax9301. [PMID: 31763455 PMCID: PMC6858253 DOI: 10.1126/sciadv.aax9301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
Understanding atomic-scale wear is crucial to avoid device failure. Atomic-scale wear differs from macroscale wear because chemical reactions and interactions at the friction interface are dominant in atomic-scale tribological behaviors, instead of macroscale properties, such as material strength and hardness. It is particularly challenging to reveal interfacial reactions and atomic-scale wear mechanisms. Here, our operando friction experiments with hydrogenated diamond-like carbon (DLC) in vacuum demonstrate the triboemission of various hydrocarbon molecules from the DLC friction interface, indicating its atomic-scale chemical wear. Furthermore, our reactive molecular dynamics simulations reveal that this triboemission of hydrocarbon molecules induces the atomic-scale mechanical wear of DLC. As the hydrogen concentration in hydrogenated DLC increases, the chemical wear increases while mechanical wear decreases, indicating an opposite effect of hydrogen concentration on chemical and mechanical wear. Consequently, the total wear shows a concave hydrogen concentration dependence, with an optimal hydrogen concentration for wear reduction of around 20%.
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Affiliation(s)
- Yang Wang
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Department of Mechanical Systems Engineering, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki-aza-aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Naohiro Yamada
- Department of Mechanical Systems Engineering, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki-aza-aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Jingxiang Xu
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- College of Engineering Science and Technology, Shanghai Ocean University, Shanghai 201306, China
| | - Jing Zhang
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Qian Chen
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Yusuke Ootani
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Yuji Higuchi
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Nobuki Ozawa
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Maria-Isabel De Barros Bouchet
- Laboratory of Tribology and System Dynamics, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue 69134, Ecully Cedex, France
| | - Jean Michel Martin
- Laboratory of Tribology and System Dynamics, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue 69134, Ecully Cedex, France
| | - Shigeyuki Mori
- Faculty of Engineering, Iwate University, 4-3-5 Ueda, Morioka, Iwate 020-8551, Japan
| | - Koshi Adachi
- Department of Mechanical Systems Engineering, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki-aza-aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Momoji Kubo
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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7
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Ta D, Tieu A, Zhu H, Le M, Ta T, Tran V, Wan S. Physical and chemical insights into molecular adsorption of copolymer’s monomers on Rutile surface. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2018.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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8
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Significance of an in-situ generated boundary film on tribocorrosion behavior of polymer-metal sliding pair. J Colloid Interface Sci 2018; 518:263-276. [DOI: 10.1016/j.jcis.2018.02.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 02/12/2018] [Accepted: 02/12/2018] [Indexed: 11/23/2022]
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9
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Zhang Y, Cai T, Shang W, Liu D, Guo Q, Liu S. Facile synthesis of photoluminescent inorganic–organic hybrid carbon dots codoped with B and N: towards an efficient lubrication additive. Dalton Trans 2017; 46:12306-12312. [DOI: 10.1039/c7dt02389h] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An inorganic-organic carbon dots consisting of an ionic liquid moiety inserted in the carbon skeleton has been synthesized and verified to be a high-performance anti-wear and friction-reducing lubricant additives in poly(ethylene glycol)(PEG).
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Affiliation(s)
- Yunxiao Zhang
- School of Materials Science and Engineering
- Shanghai University
- Shanghai
- China
- Ningbo Institute of Materials Technology and Engineering
| | - Tao Cai
- Ningbo Institute of Materials Technology and Engineering
- Chinese Academy of Sciences
- Ningbo City
- P.R. China
| | - Wangji Shang
- School of Materials Science and Engineering
- Shanghai University
- Shanghai
- China
- Ningbo Institute of Materials Technology and Engineering
| | - Dan Liu
- Ningbo Institute of Materials Technology and Engineering
- Chinese Academy of Sciences
- Ningbo City
- P.R. China
| | - Qiang Guo
- School of Materials Science and Engineering
- Shanghai University
- Shanghai
- China
| | - Shenggao Liu
- Ningbo Institute of Materials Technology and Engineering
- Chinese Academy of Sciences
- Ningbo City
- P.R. China
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10
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Zhang W, Cao Y, Tian P, Guo F, Tian Y, Zheng W, Ji X, Liu J. Soluble, Exfoliated Two-Dimensional Nanosheets as Excellent Aqueous Lubricants. ACS APPLIED MATERIALS & INTERFACES 2016; 8:32440-32449. [PMID: 27933826 DOI: 10.1021/acsami.6b09752] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Dispersion in water of two-dimensional (2D) nanosheets is conducive to their practical applications in fundamental science communities due to their abundance, low cost, and ecofriendliness. However, it is difficult to achieve stable aqueous 2D material suspensions because of the intrinsic hydrophobic properties of the layered materials. Here, we report an effective and economic way of producing various 2D nanosheets (h-BN, MoS2, MoSe2, WS2, and graphene) as aqueous dispersions using carbon quantum dots (CQDs) as exfoliation agents and stabilizers. The dispersion was prepared through a liquid phase exfoliation. The as-synthesized stable 2D nanosheets based dispersions were characterized by UV-vis, HRTEM, AFM, Raman, XPS, and XRD. The solutions based on CQD decorated 2D nanosheets were utilized as aqueous lubricants, which realized a friction coefficient as low as 0.02 and even achieved a superlubricity under certain working conditions. The excellent lubricating properties were attributed to the synergetic effects of the 2D nanosheets and CQDs, such as good dispersion stability and easy-sliding interlayer structure. This work thus proposes a novel strategy for the design and preparation of high-performance water based green lubricants.
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Affiliation(s)
- Wenling Zhang
- College of Materials Science and Engineering, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University , Qingdao 266071, China
| | - Yanlin Cao
- College of Materials Science and Engineering, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University , Qingdao 266071, China
| | - Pengyi Tian
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, China
| | - Fei Guo
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, China
| | - Yu Tian
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, China
| | - Wen Zheng
- College of Materials Science and Engineering, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University , Qingdao 266071, China
| | - Xuqiang Ji
- College of Materials Science and Engineering, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University , Qingdao 266071, China
| | - Jingquan Liu
- College of Materials Science and Engineering, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University , Qingdao 266071, China
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