1
|
Dong C, Liu Y, Meng Y, Du S, Zhu S, Tian Y, Ma L. Ion-specific ice provides a facile approach for reducing ice friction. J Colloid Interface Sci 2024; 675:451-460. [PMID: 38981254 DOI: 10.1016/j.jcis.2024.07.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 07/01/2024] [Accepted: 07/02/2024] [Indexed: 07/11/2024]
Abstract
HYPOTHESIS Ice friction plays a crucial role in both basic study and practical use. Various strategies for controlling ice friction have been developed. However, one unsolved puzzle regarding ice friction is the effect of ion-ice interplay on its tribological properties. EXPERIMENTS AND SIMULATIONS Here, we conducted ice friction experiments and summarized the specific effects of hydrated ions on ice friction. By selecting cations and anions, the coefficient of ice friction can be reduced by more than 70 percent. Experimental spectra, low-field nuclear magnetic resonance (LF-NMR), density functional theory (DFT) calculations, and Molecular dynamics (MD) simulations demonstrated that the addition of ions could break the H-bonds in water. FINDINGS The link between the charge density of ions and the coefficients of ice friction was revealed. A part of the ice structure was changed from an ice-like to a liquid-like interfacial water structure with the addition of ions. Lower charge density ions led to weaker ionic forces with the water molecules in the immobilized water layer, resulting in free water molecules increasing in the lubricating layer. This study provides guidance for preparing ice-making solutions with low friction coefficients and a fuller understanding of the interfacial water structure at low temperatures.
Collapse
Affiliation(s)
- Chang Dong
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Yuan Liu
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Yanan Meng
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Shaonan Du
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Shicai Zhu
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Yu Tian
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Liran Ma
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China.
| |
Collapse
|
2
|
Zhang Y, Jin D, Tivony R, Kampf N, Klein J. Cell-inspired, massive electromodulation of friction via transmembrane fields across lipid bilayers. NATURE MATERIALS 2024:10.1038/s41563-024-01926-9. [PMID: 38914644 DOI: 10.1038/s41563-024-01926-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 05/16/2024] [Indexed: 06/26/2024]
Abstract
Transient electric fields across cell bilayer membranes can lead to electroporation and cell fusion, effects crucial to cell viability whose biological implications have been extensively studied. However, little is known about these behaviours in a materials context. Here we find that transmembrane electric fields can lead to a massive, reversible modulation of the sliding friction between surfaces coated with lipid-bilayer membranes-a 200-fold variation, up to two orders of magnitude greater than that achieved to date. Atomistic simulations reveal that the transverse fields, resembling those at cell membranes, lead to fully reversible electroporation of the confined bilayers and the formation of inter-bilayer bridges analogous to the stalks preceding intermembrane fusion. These increase the interfacial dissipation through reduced hydration at the slip plane, forcing it to revert in part from the low-dissipation, hydrated lipid-headgroup plane to the intra-bilayer, high-dissipation acyl tail interface. Our results demonstrate that lipid bilayers under transmembrane electric fields can have striking materials modification properties.
Collapse
Affiliation(s)
- Yu Zhang
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Di Jin
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel.
| | - Ran Tivony
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
- Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Nir Kampf
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Jacob Klein
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel.
| |
Collapse
|
3
|
An R, Wu N, Gao Q, Dong Y, Laaksonen A, Shah FU, Ji X, Fuchs H. Integrative studies of ionic liquid interface layers: bridging experiments, theoretical models and simulations. NANOSCALE HORIZONS 2024; 9:506-535. [PMID: 38356335 DOI: 10.1039/d4nh00007b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
Ionic liquids (ILs) are a class of salts existing in the liquid state below 100 °C, possessing low volatility, high thermal stability as well as many highly attractive solvent and electrochemical capabilities, etc., making them highly tunable for a great variety of applications, such as lubricants, electrolytes, and soft functional materials. In many applications, ILs are first either physi- or chemisorbed on a solid surface to successively create more functional materials. The functions of ILs at solid surfaces can differ considerably from those of bulk ILs, mainly due to distinct interfacial layers with tunable structures resulting in new ionic liquid interface layer properties and enhanced performance. Due to an almost infinite number of possible combinations among the cations and anions to form ILs, the diversity of various solid surfaces, as well as different external conditions and stimuli, a detailed molecular-level understanding of their structure-property relationship is of utmost significance for a judicious design of IL-solid interfaces with appropriate properties for task-specific applications. Many experimental techniques, such as atomic force microscopy, surface force apparatus, and so on, have been used for studying the ion structuring of the IL interface layer. Molecular Dynamics simulations have been widely used to investigate the microscopic behavior of the IL interface layer. To interpret and clarify the IL structure and dynamics as well as to predict their properties, it is always beneficial to combine both experiments and simulations as close as possible. In another theoretical model development to bridge the structure and properties of the IL interface layer with performance, thermodynamic prediction & property modeling has been demonstrated as an effective tool to add the properties and function of the studied nanomaterials. Herein, we present recent findings from applying the multiscale triangle "experiment-simulation-thermodynamic modeling" in the studies of ion structuring of ILs in the vicinity of solid surfaces, as well as how it qualitatively and quantitatively correlates to the overall ILs properties, performance, and function. We introduce the most common techniques behind "experiment-simulation-thermodynamic modeling" and how they are applied for studying the IL interface layer structuring, and we highlight the possibilities of the IL interface layer structuring in applications such as lubrication and energy storage.
Collapse
Affiliation(s)
- Rong An
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Nanhua Wu
- Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
| | - Qingwei Gao
- College of Environmental and Chemical Engineering, Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power, Shanghai University of Electric Power, Shanghai 200090, China
| | - Yihui Dong
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Aatto Laaksonen
- Energy Engineering, Division of Energy Science, Luleå University of Technology, 97187 Luleå, Sweden.
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
- Center of Advanced Research in Bionanoconjugates and Biopolymers, ''Petru Poni" Institute of Macromolecular Chemistry, Iasi 700469, Romania
- State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Faiz Ullah Shah
- Chemistry of Interfaces, Luleå University of Technology, 97187 Luleå, Sweden
| | - Xiaoyan Ji
- Energy Engineering, Division of Energy Science, Luleå University of Technology, 97187 Luleå, Sweden.
| | - Harald Fuchs
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
- Center for Nanotechnology (CeNTech), Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
| |
Collapse
|
4
|
Hayler HJ, Groves TS, Guerrini A, Southam A, Zheng W, Perkin S. The surface force balance: direct measurement of interactions in fluids and soft matter. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:046601. [PMID: 38382100 DOI: 10.1088/1361-6633/ad2b9b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/21/2024] [Indexed: 02/23/2024]
Abstract
Over the last half-century, direct measurements of surface forces have been instrumental in the exploration of a multitude of phenomena in liquid, soft, and biological matter. Measurements of van der Waals interactions, electrostatic interactions, hydrophobic interactions, structural forces, depletion forces, and many other effects have checked and challenged theoretical predictions and motivated new models and understanding. The gold-standard instrument for these measurements is thesurface force balance(SFB), orsurface forces apparatus, where interferometry is used to detect the interaction force and distance between two atomically smooth planes, with 0.1 nm resolution, over separations from about 1 µm down to contact. The measured interaction forcevs.distance gives access to the free energy of interaction across the fluid film; a fundamental quantity whose general form and subtle features reveal the underlying molecular and surface interactions and their variation. Motivated by new challenges in emerging fields of research, such as energy storage, biomaterials, non-equilibrium and driven systems, innovations to the apparatus are now clearing the way for new discoveries. It is now possible to measure interaction forces (and free energies) with control of electric field, surface potential, surface chemistry; to measure time-dependent effects; and to determine structurein situ. Here, we provide an overview the operating principles and capabilities of the SFB with particular focus on the recent developments and future possibilities of this remarkable technique.
Collapse
Affiliation(s)
- Hannah J Hayler
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Timothy S Groves
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Aurora Guerrini
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Astrid Southam
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Weichao Zheng
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Susan Perkin
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| |
Collapse
|
5
|
Hayler H, Hallett JE, Perkin S. Hydrogen Bond Donors Dictate the Frictional Response in Deep Eutectic Solvents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:5695-5700. [PMID: 38444101 PMCID: PMC10956492 DOI: 10.1021/acs.langmuir.3c03303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 03/07/2024]
Abstract
Deep eutectic solvents (DESs) show promise as boundary lubricants between sliding surfaces, taking advantage of their physical stability, chemical stability, and tunability. Here, we study friction forces across nanofilms of two archetypal DES mixtures: choline chloride + ethylene glycol and choline chloride + glycerol. Using a surface force balance, we control the film thickness (to subnanometer precision) and determine the friction force simultaneously. Measurements are made at different mole fractions of the choline chloride salt and the molecular solvent, allowing us to determine the role of each species in the observed behavior. We find that the nature of the molecular solvent is dominant in determining the lubrication behavior, while the fraction of ChCl is relatively less important. By analyzing the steps in friction and the gradient of friction with load as the layers squeeze away from between the surfaces, we learn various mechanistic aspects of lubrication across the DES nanofilms of relevance to design and optimization of these promising fluids.
Collapse
Affiliation(s)
- Hannah
J. Hayler
- Physical
and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, U.K.
| | - James E. Hallett
- Department
of Chemistry, School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights Campus, Reading RG6 6AD, U.K.
| | - Susan Perkin
- Physical
and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, U.K.
| |
Collapse
|
6
|
Li S, Pilkington GA, Mehler F, Hammond OS, Boudier A, Vorobiev A, Glavatskih S, Rutland MW. Tuneable interphase transitions in ionic liquid/carrier systems via voltage control. J Colloid Interface Sci 2023; 652:1240-1249. [PMID: 37657223 DOI: 10.1016/j.jcis.2023.08.111] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 08/09/2023] [Accepted: 08/18/2023] [Indexed: 09/03/2023]
Abstract
The structure and interaction of ionic liquids (ILs) influence their interfacial composition, and their arrangement (i.e., electric double-layer (EDL) structure), can be controlled by an electric field. Here, we employed a quartz crystal microbalance (QCM) to study the electrical response of two non-halogenated phosphonium orthoborate ILs, dissolved in a polar solvent at the interface. The response is influenced by the applied voltage, the structure of the ions, and the solvent polarizability. One IL showed anomalous electro-responsivity, suggesting a self-assembly bilayer structure of the IL cation at the gold interface, which transitions to a typical EDL structure at higher positive potential. Neutron reflectivity (NR) confirmed this interfacial structuring and compositional changes at the electrified gold surface. A cation-dominated self-assembly structure is observed for negative and neutral voltages, which abruptly transitions to an anion-rich interfacial layer at positive voltages. An interphase transition explains the electro-responsive behaviour of self-assembling IL/carrier systems, pertinent for ILs in advanced tribological and electrochemical contexts.
Collapse
Affiliation(s)
- Sichao Li
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Georgia A Pilkington
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Filip Mehler
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Oliver S Hammond
- Department of Materials and Environmental Chemistry, Stockholm University, SE-114 18 Stockholm, Sweden; Department of Biological and Chemical Engineering, Aarhus University, Aarhus C 8000 Denmark
| | - Anthony Boudier
- Department of Materials and Environmental Chemistry, Stockholm University, SE-114 18 Stockholm, Sweden
| | - Alexei Vorobiev
- Department of Physics and Astronomy, Division of Materials Physics, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Sergei Glavatskih
- System and Component Design, Department of Engineering Design, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden; School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia; Department of Electromechanical, Systems and Metal Engineering, Ghent University, B-9052 Ghent, Belgium
| | - Mark W Rutland
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden; School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia; Bioeconomy and Health Department Materials and Surface Design, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden; Laboratoire de Tribologie et Dynamique des Systèmes, École Centrale de Lyon, 69134 Ecully Cedex, France.
| |
Collapse
|
7
|
Zhang X, Han M, Espinosa-Marzal RM. Thin-Film Rheology and Tribology of Imidazolium Ionic Liquids. ACS APPLIED MATERIALS & INTERFACES 2023; 15:45485-45497. [PMID: 37721996 PMCID: PMC10540134 DOI: 10.1021/acsami.3c10018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 09/05/2023] [Indexed: 09/20/2023]
Abstract
Ionic liquids (ILs) are organic molten salts with low-temperature melting points that hold promise as next-generation environmentally friendly boundary lubricants. This work examines the relationship between tribological and rheological behavior of thin films of five imidazolium ILs using a surface force apparatus to elucidate lubrication mechanisms. When confined to films of a few nanometers, the rheological properties change drastically as a function of the number of confined ion layers; not only the viscosity increases by several orders of magnitude but ILs can also undergo a transition from Newtonian to viscoelastic fluid and to an elastic solid. This behavior can be justified by the confinement-induced formation of supramolecular clusters with long relaxation times. The quantized friction coefficient is explained from the perspective of the strain relaxation via diffusion of these supramolecular clusters, where higher friction correlates with longer relaxation times. A deviation from this behavior is observed only for 1-ethyl-3-methylimidazolium ethylsulfate ([C2C1Im][EtSO4]), characterized by strong hydrogen bonding; this is hypothesized to restrict the reorganization of the confined IL into clusters and hinder (visco)elastic behavior, which is consistent with the smallest friction coefficient measured for this IL. We also investigate the contrasting influence of traces of water on the thin-film rheology and tribology of a hydrophobic IL, 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate, [C2C1Im][FAP], and a hydrophilic IL, [C2C1Im][EtSO4]. [C2C1Im][EtSO4] remains Newtonian under both dry and humid conditions and provides the best lubrication, while [C2C1Im][FAP], characterized by a prominent solid-like behavior under both conditions, is a poor lubricant. The results of this study may inspire molecular designs to enable efficient IL lubrication.
Collapse
Affiliation(s)
- Xuhui Zhang
- Department
of Civil and Environmental Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Mengwei Han
- Department
of Civil and Environmental Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Rosa M. Espinosa-Marzal
- Department
of Civil and Environmental Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
- Department
of Materials Science and Engineering, University
of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| |
Collapse
|
8
|
Lu Y, Wang Y, Huo F, Chen W, Ma M, Ding WL, He H, Zhang S. Ultralow Friction and High Robustness of Monolayer Ionic Liquids. ACS NANO 2022; 16:16471-16480. [PMID: 36222622 DOI: 10.1021/acsnano.2c05779] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Ultralow friction between interacting surfaces in relative motion is of vital importance in many pure and applied sciences. We found that surfaces bearing ordered monolayer ionic liquids (ILs) can have friction coefficient μ values as low as 0.001 at pressures up to 78 MPa and exhibit good structure recoverability. This extreme lubrication is attributed primarily to the ordered striped structure driven by the "atomic-locking" effect between carbon atoms on the alkyl chain of ILs and graphite. The longer alkyl chain has lower μ values, and the stripe periodicity is decisive in reducing energy dissipation during the sliding process. In combination with simulation, the alternate atomic-scale ordered and disordered ionic regions were recognized, whose ratio fundamentally determines the μ values and lubrication mechanism. This finding is an important step toward the practical utilization of ILs with negligible vapor pressure as superlubricating materials in future technological applications operating under extreme conditions.
Collapse
Affiliation(s)
- Yumiao Lu
- Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yanlei Wang
- Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Feng Huo
- Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Wei Chen
- Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Ming Ma
- Department of Mechanical Engineering, State Key Laboratory of Tribology in Advanced Equipment (SKLT), Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Wei-Lu Ding
- Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Hongyan He
- Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Suojiang Zhang
- Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| |
Collapse
|
9
|
Bresme F, Kornyshev AA, Perkin S, Urbakh M. Electrotunable friction with ionic liquid lubricants. NATURE MATERIALS 2022; 21:848-858. [PMID: 35761059 DOI: 10.1038/s41563-022-01273-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
Room-temperature ionic liquids and their mixtures with organic solvents as lubricants open a route to control lubricity at the nanoscale via electrical polarization of the sliding surfaces. Electronanotribology is an emerging field that has a potential to realize in situ control of friction-that is, turning the friction on and off on demand. However, fulfilling its promise needs more research. Here we provide an overview of this emerging research area, from its birth to the current state, reviewing the main achievements in non-equilibrium molecular dynamics simulations and experiments using atomic force microscopes and surface force apparatus. We also present a discussion of the challenges that need to be solved for future applications of electrotunable friction.
Collapse
Affiliation(s)
- Fernando Bresme
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, UK.
| | - Alexei A Kornyshev
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, UK.
| | - Susan Perkin
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK.
| | - Michael Urbakh
- Department of Physical Chemistry, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences, and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv, Israel.
| |
Collapse
|
10
|
Wang B, Li L. Direct observation of the double-layering quantized growth of mica-confined ionic liquids. NANOSCALE 2021; 13:17961-17971. [PMID: 34700337 DOI: 10.1039/d1nr05437f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Since the interface between ionic liquids (ILs) and solids always plays a critical role in important applications such as coating, lubrication, energy storage and catalysis, it is essential to unravel the molecular structure and dynamics of ILs confined to solid surfaces. Here we report direct observation of a unique double-layering quantized growth of three IL (i.e. [Emim][FAP], [Bmim][FAP] and [Hmim][FAP]) nanofilms on mica. AFM results show that the IL nanofilms initially grow only by covering more surface areas at the constant film thickness of 2 monolayers (ML) until a quantized increase in the film thickness by another 2 ML occurs. Based on the AFM results, we propose a double-layering model describing the molecular structure of IL cations and anions on the mica surface. The interesting double-layering structure can be explained as the result of several competing interactions at the IL-mica interface. Meanwhile, the time-dependent AFM results indicate that the topography of IL nanofilms could change with time and mobility of the nanofilm is lower for ILs with longer alkyl chains, which can be attributed to the stronger solvophobic interaction. The findings here have important implications on the molecular structure and dynamics of ILs confined to solid surfaces.
Collapse
Affiliation(s)
- Bingchen Wang
- Department of Chemical & Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Lei Li
- Department of Chemical & Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| |
Collapse
|
11
|
Ntim S, Sulpizi M. Effects of shear flow on the structure and dynamics of ionic liquids in a metallic nanoconfinement. Phys Chem Chem Phys 2021; 23:24357-24364. [PMID: 34676844 DOI: 10.1039/d1cp01055g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
It has been shown that a weak shear can induce crystallisation in a disordered, glassy state. In this study, we use molecular dynamics simulations in order to investigate the out-of-equilibrium properties of [BMIM][BF4] confined between metal slabs. In particular, we want to understand the extent to which the shear flow modifies the interfacial properties. In particular, the questions we address here are (i) is the shear able to promote the crystalline phase in [BMIM][BF4]? (ii) Can, as a consequence of shear flow, a solid-like layer develop at the interface with a metallic surface? (iii) What are the tribological properties of nanoconfined [BMIM][BF4]? We find that the system behaves quite differently from the ideal linear Couette flow. Indeed, the portion of fluid closer to the shearing slabs behaves as a disordered, solid-like layer, which, under the investigated conditions extends to a few nanometres. The linear velocity regime is only recovered in the central region of the ionic liquid slab. The formation of such a solid-like glassy rather than crystalline layer is in agreement with recent mechanical impedance measurements performed on nano-confined ionic liquids.
Collapse
Affiliation(s)
- Samuel Ntim
- Institut für Physik, Johannes Gutenberg Universität, Staudingerweg 7, 55128-Mainz, Germany.
| | - Marialore Sulpizi
- Institut für Physik, Johannes Gutenberg Universität, Staudingerweg 7, 55128-Mainz, Germany.
| |
Collapse
|
12
|
Burgess D, Li N, Rosik N, Fryer PJ, McRobbie I, Zhang H, Zhang ZJ. Surface-Grafted Poly(ionic liquid) that Lubricates in Both Non-polar and Polar Solvents. ACS Macro Lett 2021; 10:907-913. [PMID: 34306821 PMCID: PMC8296680 DOI: 10.1021/acsmacrolett.1c00174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 06/22/2021] [Indexed: 11/29/2022]
Abstract
![]()
We show that a surface-grafted
polymer brush, 1-n-butyl-3-vinyl imidazolium bromide-based
poly(ionic liquids), is
able to reduce the interfacial friction by up to 66% and 42% in dodecane
and water, respectively. AFM-based force spectroscopy reveals that
the polymer brush adopts distinctively different interfacial conformations:
swollen in water but collapsed in dodecane. Minimal surface adhesion
was observed with both polymer conformations, which can be attributed
to steric repulsion as the result of a swollen conformation in water
or surface solvation when the hydrophobic fraction of the polymer
was exposed to the dodecane. The work brings additional insight on
the polymer lubrication mechanism, which expands the possible design
of the polymer architecture for interfacial lubrication and modification.
Collapse
Affiliation(s)
- David Burgess
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Na Li
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, No. 122 Luoshi Road, Wuhan, 430070, People’s Republic of China
| | - Nicole Rosik
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Peter J. Fryer
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Ian McRobbie
- Innospec Inc., Innospec Manufacturing Park, Oil Sites Road, Ellesmere Port, Cheshire, CH65 4EY, United Kingdom
| | - Haining Zhang
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, No. 122 Luoshi Road, Wuhan, 430070, People’s Republic of China
| | - Zhenyu J. Zhang
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| |
Collapse
|
13
|
Pilkington GA, Welbourn R, Oleshkevych A, Watanabe S, Pedraz P, Radiom M, Glavatskih S, Rutland MW. Effect of water on the electroresponsive structuring and friction in dilute and concentrated ionic liquid lubricant mixtures. Phys Chem Chem Phys 2020; 22:28191-28201. [PMID: 33295339 DOI: 10.1039/d0cp05110a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of water on the electroactive structuring of a tribologically relevant ionic liquid (IL) when dispersed in a polar solvent has been investigated at a gold electrode interface using neutron reflectivity (NR). For all solutions studied, the addition of small amounts of water led to clear changes in electroactive structuring of the IL at the electrode interface, which was largely determined by the bulk IL concentration. At a dilute IL concentration, the presence of water gave rise to a swollen interfacial structuring, which exhibited a greater degree of electroresponsivity with applied potential compared to an equivalent dry solution. Conversely, for a concentrated IL solution, the presence of water led to an overall thinning of the interfacial region and a crowding-like structuring, within which the composition of the inner layer IL layers varied systematically with applied potential. Complementary nanotribotronic atomic force microscopy (AFM) measurements performed for the same IL concentration, in dry and ambient conditions, show that the presence of water reduces the lubricity of the IL boundary layers. However, consistent with the observed changes in the IL layers observed by NR, reversible and systematic control of the friction coefficient with applied potential was still achievable. Combined, these measurements provide valuable insight into the implications of water on the interfacial properties of ILs at electrified interfaces, which inevitably will determine their applicability in tribotronic and electrochemical contexts.
Collapse
Affiliation(s)
- Georgia A Pilkington
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Yang J, Lian C, Liu H. Chain length matters: Structural transition and capacitance of room temperature ionic liquids in nanoporous electrodes. Chem Eng Sci 2020. [DOI: 10.1016/j.ces.2020.115927] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
15
|
Di Lecce S, Kornyshev AA, Urbakh M, Bresme F. Lateral Ordering in Nanoscale Ionic Liquid Films between Charged Surfaces Enhances Lubricity. ACS NANO 2020; 14:13256-13267. [PMID: 33054180 DOI: 10.1021/acsnano.0c05043] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Electric fields modify the structural and dynamical properties of room temperature ionic liquids (RTILs) providing a physical principle to develop tunable lubrication devices. Using nonequilibrium molecular dynamics atomistic simulations, we investigate the impact of the composition of imidazolium RTILs on the in-plane ordering of ionic layers in nanogaps. We consider imidazolium cations and widely used anions featuring different molecular structures, spherical ([BF4]-), elongated surfactant-like ([C2SO4]-), and elongated with a more delocalized charge ([NTf2]-). The interplay of surface charge, surface polarity, and anion geometry enables the formation of crystal-like structures in [BF4]- and [NTf2]- nanofilms, while [C2SO4]- nanofilms form disordered layers. We study how the ordering of the ionic liquid lubricant in the nanogap affects friction. Counterintuitively, we find that the friction force decreases with the ability of the RTILs to form crystal-like structures in the confined region. The crystallization can be activated or inhibited by changing the polarity of the surface, providing a mechanism to tune friction with electric fields.
Collapse
Affiliation(s)
- Silvia Di Lecce
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, U.K
| | - Alexei A Kornyshev
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, U.K
| | - Michael Urbakh
- School of Chemistry and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Fernando Bresme
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, U.K
| |
Collapse
|
16
|
Hallett JE, Hayler HJ, Perkin S. Nanolubrication in deep eutectic solvents. Phys Chem Chem Phys 2020; 22:20253-20264. [PMID: 32966447 DOI: 10.1039/d0cp03787g] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report surface force balance measurements of the normal surface force and friction between two mica surfaces separated by a nanofilm of the deep eutectic solvent ethaline. Ethaline, a 1 : 2 mixture of choline chloride and ethylene glycol, was studied under dry conditions, under ambient conditions and with added water, revealing surface structural layers and quantised frictional response highly sensitive to water content, including regions of super-lubric behaviour under dry conditions and with added water. We also report exceptionally long-ranged electrostatic repulsion far in excess of that predicted by Debye-Hückel theory for a system with such high electrolyte content, consistent with previously reported observations of "underscreening" in ionic liquid and concentrated aqueous electrolyte systems [Smith et al., J. Phys. Chem. Lett., 2016, 7(12), 2157].
Collapse
Affiliation(s)
- James E Hallett
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Hannah J Hayler
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Susan Perkin
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
| |
Collapse
|
17
|
Dong R, Bao L, Yu Q, Wu Y, Ma Z, Zhang J, Cai M, Zhou F, Liu W. Effect of Electric Potential and Chain Length on Tribological Performances of Ionic Liquids as Additives for Aqueous Systems and Molecular Dynamics Simulations. ACS APPLIED MATERIALS & INTERFACES 2020; 12:39910-39919. [PMID: 32804469 DOI: 10.1021/acsami.0c11016] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
As pure lubricants, ILs performed very well by forming the classical self-assembly bilayer at the sliding interface. The interface mechanism is still not clear in a very polar, e.g., water-based lubricating system. In this work, the interfacial absorption and tribological behavior of carboxylic alkanolamine ionic liquids (CAILs) serving as aqueous lubricating additives were studied by applying positive and negative potentials on the friction pair, accompanied by the comprehensive discussion of data from critical micelle concentration, quartz crystal microbalance, ECR, and MD results. The results reveal that the adsorption behavior, unexpectedly, was affected by the high polarity of H2O, where a less dense double-layer structure is observed at the interface by model imitation. Conversely, the monomolecular adsorption layer constructed electrostatically between the polar head (-COO-) and the positive base dominates the tribofilm. Meanwhile, the cations are partially accumulating around anions in the presence of static electricity, which does not form a neat and dense one-to-one corresponding cation-anion pair. In the solution, the IL maintains a state of dissociation and minor agglomeration. Furthermore, an increase in alkyl chains contributes to the thickness of the protective film generated by CAILs on the sliding asperity. Eventually, the synergistic effect from physical adsorption and the tribochemical reaction is responsible for excellent lubricity and antiwear performance of CAILs.
Collapse
Affiliation(s)
- Rui Dong
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Luyao Bao
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Qiangliang Yu
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Yang Wu
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Zhengfeng Ma
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Jiaying Zhang
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meirong Cai
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Feng Zhou
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Weimin Liu
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| |
Collapse
|
18
|
Wang YL, Li B, Sarman S, Mocci F, Lu ZY, Yuan J, Laaksonen A, Fayer MD. Microstructural and Dynamical Heterogeneities in Ionic Liquids. Chem Rev 2020; 120:5798-5877. [PMID: 32292036 PMCID: PMC7349628 DOI: 10.1021/acs.chemrev.9b00693] [Citation(s) in RCA: 192] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation-anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
Collapse
Affiliation(s)
- Yong-Lei Wang
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Bin Li
- School
of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China
| | - Sten Sarman
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Francesca Mocci
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy
| | - Zhong-Yuan Lu
- State
Key Laboratory of Supramolecular Structure and Materials, Institute
of Theoretical Chemistry, Jilin University, Changchun 130021, P. R. China
| | - Jiayin Yuan
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Aatto Laaksonen
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
- State
Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
- Centre of
Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry Aleea Grigore Ghica-Voda, 41A, 700487 Iasi, Romania
- Department
of Engineering Sciences and Mathematics, Division of Energy Science, Luleå University of Technology, SE-97187 Luleå, Sweden
| | - Michael D. Fayer
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| |
Collapse
|
19
|
Chen M, Feng G, Qiao R. Water-in-salt electrolytes: An interfacial perspective. Curr Opin Colloid Interface Sci 2020. [DOI: 10.1016/j.cocis.2019.12.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
20
|
Di Lecce S, Kornyshev AA, Urbakh M, Bresme F. Electrotunable Lubrication with Ionic Liquids: the Effects of Cation Chain Length and Substrate Polarity. ACS APPLIED MATERIALS & INTERFACES 2020; 12:4105-4113. [PMID: 31875392 DOI: 10.1021/acsami.9b19283] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electrotunable lubrication with ionic liquids (ILs) provides dynamic control of friction with the prospect to achieve superlubrication. We investigate the dependence of the frictional and structural forces with 1-n,2-methyl-imidazolium tetrafluoroborate [CnMIM]+[BF4]- (n = 2, 4, 6) ILs as a lubricant on the molecular structure of the liquid, normal load, and polarity of the electrodes. Using non-equilibrium molecular dynamics simulations and coarse-grained force-fields, we show that the friction force depends significantly on the chain length of the cation. ILs containing cations with shorter aliphatic chains show lower friction forces, ∼40% for n = 2 as compared to the n = 6 case, and more resistance to squeeze-out by external loads. The normal load defines the dynamic regime of friction, and it determines maxima in the friction force at specific surface charges. At relatively low normal loads, ∼10 MPa, the velocity profile in the confined region resembles a Couette type flow, whereas at high loads, >200 MPa, the motion of the ions is highly correlated and the velocity profile resembles a "plug" flow. Different dynamic regimes result in distinctive slippage planes, located either at the IL-electrode interface or in the interior of the film, which ultimately lead, at high loads, to the observation of maxima in the friction force at specific surface charge densities. Instead, at low loads the maxima are not observed, and the friction is found to monotonously increase with the surface charge. Friction with [CnMIM]+[BF4]- as a lubricant is reduced when the liquid is confined between positively charged electrodes. This is due to better lubricating properties and enhanced resistance to squeeze out when the anion [BF4]- is in direct contact with the electrode.
Collapse
Affiliation(s)
- Silvia Di Lecce
- Department of Chemistry, Molecular Sciences Research Hub , Imperial College , W12 0BZ London , U.K
| | - Alexei A Kornyshev
- Department of Chemistry, Molecular Sciences Research Hub , Imperial College , W12 0BZ London , U.K
| | - Michael Urbakh
- School of Chemistry and The Sackler Center for Computational Molecular and Materials Science , Tel Aviv University , Tel Aviv 6997801 , Israel
| | - Fernando Bresme
- Department of Chemistry, Molecular Sciences Research Hub , Imperial College , W12 0BZ London , U.K
| |
Collapse
|
21
|
Fajardo OY, Di Lecce S, Bresme F. Molecular dynamics simulation of imidazolium C nMIM-BF 4 ionic liquids using a coarse grained force-field. Phys Chem Chem Phys 2020; 22:1682-1692. [PMID: 31895366 DOI: 10.1039/c9cp05932f] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ionic liquids feature thermophysical properties that are of interest in solvents, energy storage materials and tunable lubrication applications. Here we use new Coarse Grained (CG) models to investigate the structure, dynamics and interfacial properties of the [C2-8MIM][BF4] family of ionic liquids (ILs). The simulated equation of state and diffusion coefficients are in good agreement with experimental data and with all-atom force-fields. We quantify the nano-structure and liquid-vapour interfacial properties of the ILs as a function of the size of the imidazolium cation. The computational efficiency of the CG models enables the simulation of very long time scales (100's of nanoseconds), which are needed to resolve the dynamic and interfacial properties of ILs containing cations with long aliphatic chains. For [C>4MIM] [BF4] the break in symmetry associated to the liquid-vapour interface induces nanostructuring of polar and non-polar domains in the direction perpendicular to the interface plane, with the inhomogeneous regions penetrating deep inside the bulk liquid, typically 5 nm for C8MIM cations.
Collapse
Affiliation(s)
- Oscar Y Fajardo
- Department of Chemistry, Molecular Sciences Research Hub Imperial College, W12 0BZ, London, UK.
| | - Silvia Di Lecce
- Department of Chemistry, Molecular Sciences Research Hub Imperial College, W12 0BZ, London, UK.
| | - Fernando Bresme
- Department of Chemistry, Molecular Sciences Research Hub Imperial College, W12 0BZ, London, UK.
| |
Collapse
|
22
|
Lhermerout R, Perkin S. A new methodology for a detailed investigation of quantized friction in ionic liquids. Phys Chem Chem Phys 2020; 22:455-466. [PMID: 31781711 DOI: 10.1039/c9cp05422g] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
When confined at the nanoscale between smooth surfaces, an ionic liquid forms a structured film responding to shear in a quantized way, i.e., with a friction coefficient indexed by the number of layers in the gap. So far, only a few experiments have been performed to study this phenomenon, because of the delicate nature of the measurements. We propose a new methodology to measure friction with a surface force balance, based on the simultaneous application of normal and lateral motions to the surfaces, allowing for a more precise, comprehensive and rapid determination of the friction response. We report on proof-of-concept experiments with an ionic liquid confined between mica surfaces in dry or wet conditions, showing the phenomenon of quantized friction with an unprecedented resolution. First, we show that the variation of the kinetic friction force with the applied load for a given layer is not linear, but can be quantitatively described by two additive contributions that are respectively proportional to the load and to the contact area. Then, we find that humidity improves the resistance of the layers to be squeezed-out and extends the range of loads in which the liquid behaves as a superlubricant, interpreted by an enhanced dissolution of the potassium ions on the mica leading to a larger surface charge. There, we note a liquid-like friction behavior, and observe in certain conditions a clear variation of the kinetic friction force over two decades of shearing velocities, that does not obey a simple Arrhenius dynamics.
Collapse
Affiliation(s)
- Romain Lhermerout
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.
| | | |
Collapse
|
23
|
Watanabe S, Pilkington GA, Oleshkevych A, Pedraz P, Radiom M, Welbourn R, Glavatskih S, Rutland MW. Interfacial structuring of non-halogenated imidazolium ionic liquids at charged surfaces: effect of alkyl chain length. Phys Chem Chem Phys 2020; 22:8450-8460. [DOI: 10.1039/d0cp00360c] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Control of the interfacial structures of ionic liquids (ILs) at charged interfaces is important to many of their applications, including in energy storage solutions, sensors and advanced lubrication technologies utilising electric fields.
Collapse
Affiliation(s)
- Seiya Watanabe
- Division of Surface and Corrosion Science
- School of Engineering Sciences in Chemistry
- Biotechnology and Health
- KTH Royal Institute of Technology
- SE-100 44 Stockholm
| | - Georgia A. Pilkington
- Division of Surface and Corrosion Science
- School of Engineering Sciences in Chemistry
- Biotechnology and Health
- KTH Royal Institute of Technology
- SE-100 44 Stockholm
| | - Anna Oleshkevych
- Division of Surface and Corrosion Science
- School of Engineering Sciences in Chemistry
- Biotechnology and Health
- KTH Royal Institute of Technology
- SE-100 44 Stockholm
| | - Patricia Pedraz
- Division of Surface and Corrosion Science
- School of Engineering Sciences in Chemistry
- Biotechnology and Health
- KTH Royal Institute of Technology
- SE-100 44 Stockholm
| | - Milad Radiom
- Division of Surface and Corrosion Science
- School of Engineering Sciences in Chemistry
- Biotechnology and Health
- KTH Royal Institute of Technology
- SE-100 44 Stockholm
| | - Rebecca Welbourn
- ISIS Neutron & Muon Source
- Rutherford Appleton Laboratory
- STFC
- Didcot
- UK
| | - Sergei Glavatskih
- System and Component Design
- Department of Machine Design
- KTH Royal Institute of Technology
- SE-100 44 Stockholm
- Sweden
| | - Mark W. Rutland
- Division of Surface and Corrosion Science
- School of Engineering Sciences in Chemistry
- Biotechnology and Health
- KTH Royal Institute of Technology
- SE-100 44 Stockholm
| |
Collapse
|
24
|
Hjalmarsson N, Bergendal E, Wang YL, Munavirov B, Wallinder D, Glavatskih S, Aastrup T, Atkin R, Furó I, Rutland MW. Electro-Responsive Surface Composition and Kinetics of an Ionic Liquid in a Polar Oil. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15692-15700. [PMID: 31581771 DOI: 10.1021/acs.langmuir.9b02119] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The quartz crystal microbalance (QCM) has been used to study how the interfacial layer of an ionic liquid dissolved in a polar oil at low weight percentages responds to changes in applied potential. The changes in surface composition at the QCM gold surface depend on both the magnitude and sign of the applied potential. The time-resolved response indicates that the relaxation kinetics are limited by the diffusion of ions in the interfacial region and not in the bulk, since there is no concentration dependence. The measured mass changes cannot be explained only in terms of simple ion exchange; the relative molecular volumes of the ions and the density changes in response to ion exclusion must be considered. The relaxation behavior of the potential between the electrodes upon disconnecting the applied potential is more complex than that observed for pure ionic liquids, but a measure of the surface charge can be extracted from the exponential decay when the rapid initial potential drop is accounted for. The adsorbed film at the gold surface consists predominantly of ionic liquid despite the low concentration, which is unsurprising given the surtactant-like structures of (some of) the ionic liquid ions. Changes in response to potential correspond to changes in the relative numbers of cations and anions, rather than a change in the oil composition. No evidence for an electric field induced change in viscosity is observed. This work shows conclusively that electric potentials can be used to control the surface composition, even in an oil-based system, and paves the way for other ion solvent studies.
Collapse
Affiliation(s)
| | | | | | | | | | - Sergei Glavatskih
- Department of Electrical Energy, Metals, Mechanical Constructions and Systems , Ghent University , B-9000 , Ghent , Belgium
| | | | - Rob Atkin
- School of Molecular Sciences , University of Western Australia , 6009 Perth , Australia
| | | | - Mark W Rutland
- Surfaces, Processes and Formulation , RISE Research Institutes of Sweden , SE-50115 Stockholm , Sweden
| |
Collapse
|
25
|
Perez-Martinez CS, Perkin S. Interfacial Structure and Boundary Lubrication of a Dicationic Ionic Liquid. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15444-15450. [PMID: 31282683 DOI: 10.1021/acs.langmuir.9b01415] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report measurements of the normal surface forces and friction forces between two mica surfaces separated by a nanofilm of dicationic ionic liquid using a Surface Force Balance. The dicationic ionic liquid 1,10-bis(3-methylimidazolium)decane di[bis(trifluoromethylsulfonyl)imide] forms a layered structure in nanoconfinement, revealed by oscillatory structural forces. Friction measurements performed at different film thicknesses display quantized friction, i.e., discontinuities in friction as layers are squeezed out and friction coefficients dependent on the number of liquid layers confined between the surfaces. The details of the friction traces indicate a liquidlike film, and, surprisingly, decreasing friction with increasing water content; we discuss possible mechanisms underlying these observations. This latter trait may be helpful in applications where ionic liquid lubricants cannot be insulated against humid environments.
Collapse
Affiliation(s)
- Carla S Perez-Martinez
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry , University of Oxford , Oxford OX1 3QZ , United Kingdom
| | - Susan Perkin
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry , University of Oxford , Oxford OX1 3QZ , United Kingdom
| |
Collapse
|
26
|
Radiom M. Ionic liquid–solid interface and applications in lubrication and energy storage. Curr Opin Colloid Interface Sci 2019. [DOI: 10.1016/j.cocis.2019.01.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
27
|
Lhermerout R, Diederichs C, Sinha S, Porfyrakis K, Perkin S. Are Buckminsterfullerenes Molecular Ball Bearings? J Phys Chem B 2019; 123:310-316. [PMID: 30525632 DOI: 10.1021/acs.jpcb.8b10472] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Buckminsterfullerenes (C60) are near-spherical molecules, which freely rotate at room temperature in the solid state and when dissolved in solution. An intriguing question arises as to whether C60 molecules can act as "molecular ball bearings," that is, preventing direct contact between two solid surfaces while simultaneously dissipating shear stress through fast rotation. To explore this, we performed measurements of friction across a solution of C60 in the boundary lubrication regime. High-resolution shear and normal force measurements between mica sheets separated by C60 solution were made using a surface force balance to provide single-asperity contact and sub-nanometer resolution in film thickness. We find that, even at a small volume fraction, C60 forms a solidlike amorphous boundary film sustaining a high normal load, suggesting that this system undergoes a glass transition under confinement. The C60 film gives rise to a low friction coefficient up to moderate applied loads, and we discuss the possible relevance of the ball-bearing effect at the molecular scale.
Collapse
Affiliation(s)
- Romain Lhermerout
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory , University of Oxford , Oxford OX1 3QZ , U.K
| | - Christophe Diederichs
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory , University of Oxford , Oxford OX1 3QZ , U.K
| | - Sapna Sinha
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , U.K
| | - Kyriakos Porfyrakis
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , U.K
| | - Susan Perkin
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory , University of Oxford , Oxford OX1 3QZ , U.K
| |
Collapse
|
28
|
Freitas AAD, Shimizu K, Smith AM, Perkin S, Canongia Lopes JN. Structure and dynamics of mica-confined films of [C10C1Pyrr][NTf2] ionic liquid. J Chem Phys 2018; 148:193808. [DOI: 10.1063/1.5007809] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Adilson Alves de Freitas
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Karina Shimizu
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Alexander M. Smith
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
- Department of Inorganic and Analytical Chemistry, University of Geneva, 1205 Geneva, Switzerland
| | - Susan Perkin
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - José Nuno Canongia Lopes
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| |
Collapse
|
29
|
Griffin LR, Browning KL, Clarke SM, Smith AM, Perkin S, Skoda MWA, Norman SE. Direct measurements of ionic liquid layering at a single mica-liquid interface and in nano-films between two mica-liquid interfaces. Phys Chem Chem Phys 2018; 19:297-304. [PMID: 27905590 DOI: 10.1039/c6cp05757h] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The layering of ionic liquids close to flat, charged interfaces has been identified previously through theoretical and some experimental measurements. Here we present evidence for oscillations in ion density ('layering') in a long chain ionic liquid (1-decyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide) near the interface with mica using two complementary approaches. Neutron reflection at the ionic liquid-mica interface is used to detect structure at a single interface, and surface force balance (SFB) measurements carried out with the same ionic liquid reveal oscillatory density in the liquid confined between two mica sheets. Our findings imply the interfacial structure is not induced by confinement alone. Structural forces between two mica surfaces extend to approximately twice the distance of the density oscillations measured at a single interface and have similar period in both cases.
Collapse
Affiliation(s)
- Lucy R Griffin
- BP Institute and Department of Chemistry, University of Cambridge, Cambridge, UK.
| | - Kathryn L Browning
- BP Institute and Department of Chemistry, University of Cambridge, Cambridge, UK.
| | - Stuart M Clarke
- BP Institute and Department of Chemistry, University of Cambridge, Cambridge, UK.
| | - Alexander M Smith
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Susan Perkin
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - M W A Skoda
- ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, UK
| | - Sarah E Norman
- ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, UK
| |
Collapse
|
30
|
Abstract
The application of ionic liquids as lubricants has attracted substantial interest over the past decade and this has produced a rich literature. The aim of this review is to summarize the main findings about frictional behavior of ionic liquids in the boundary lubrication regime. We first recall why the unusual properties of ionic liquids make them very promising lubricants, and the molecular mechanisms at the origin of their lubricating behavior. We then point out the main challenges to be overcome in order to optimise ionic liquid lubricant performance for common applications. We finally discuss their use in the context of electroactive lubrication.
Collapse
|
31
|
Li J, Luo J. Nonlinear Frictional Energy Dissipation between Silica-Adsorbed Surfactant Micelles. J Phys Chem Lett 2017; 8:2258-2262. [PMID: 28468497 DOI: 10.1021/acs.jpclett.7b00744] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The origin of energy dissipation underlies all friction processes, which is crucial in the design of extremely low friction and wear systems. Amontons's friction law shows that the frictional energy dissipation should be linear with load because of the constant friction coefficient. However, in this Letter, we present the nonlinear behavior of frictional energy dissipation in boundary lubrication with silica-adsorbed surfactant micelles. There exist two completely different friction regimes: a near-zero friction regime with very little energy dissipation and a nonlinear friction regime with a great deal of extra energy dissipation. The additional energy dissipation presents a square (nonlinear) relation with applied load, originating from the elastic deformation of the adsorbed micelle layer on the two friction surfaces, which is tightly linked to the stiffness of the micelle layer and the diameter of the contact area.
Collapse
Affiliation(s)
- Jinjin Li
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, China
| | - Jianbin Luo
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, China
| |
Collapse
|
32
|
Smith AM, Lee AA, Perkin S. Switching the Structural Force in Ionic Liquid-Solvent Mixtures by Varying Composition. PHYSICAL REVIEW LETTERS 2017; 118:096002. [PMID: 28306271 DOI: 10.1103/physrevlett.118.096002] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Indexed: 06/06/2023]
Abstract
The structure and interactions in electrolytes at high concentration have implications from energy storage to biomolecular interactions. However, many experimental observations are yet to be explained in these mixtures, which are far beyond the regime of validity of mean-field models. Here, we study the structural forces in a mixture of ionic liquid and solvent that is miscible in all proportions at room temperature. Using the surface force balance to measure the force between macroscopic smooth surfaces across the liquid mixtures, we uncover an abrupt increase in the wavelength above a threshold ion concentration. Below the threshold concentration, the wavelength is determined by the size of the solvent molecule, whereas above the threshold, it is the diameter of a cation-anion pair that determines the wavelength.
Collapse
Affiliation(s)
- Alexander M Smith
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
- Department of Inorganic and Analytical Chemistry, University of Geneva, 1205 Geneva, Switzerland
| | - Alpha A Lee
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Susan Perkin
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
| |
Collapse
|
33
|
Wang YL, Golets M, Li B, Sarman S, Laaksonen A. Interfacial Structures of Trihexyltetradecylphosphonium-bis(mandelato)borate Ionic Liquid Confined between Gold Electrodes. ACS APPLIED MATERIALS & INTERFACES 2017; 9:4976-4987. [PMID: 28099800 DOI: 10.1021/acsami.6b14429] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Atomistic molecular dynamics simulations have been performed to study microscopic the interfacial ionic structures, molecular arrangements, and orientational preferences of trihexyltetradecylphosphonium-bis(mandelato)borate ([P6,6,6,14][BMB]) ionic liquid confined between neutral and charged gold electrodes. It was found that both [P6,6,6,14] cations and [BMB] anions are coabsorbed onto neutral electrodes at different temperatures. The hexyl and tetradecyl chains in [P6,6,6,14] cations lie preferentially flat on neutral electrodes. The oxalato and phenyl rings in [BMB] anions are characterized by alternative parallel-perpendicular orientations in the mixed innermost ionic layer adjacent to neutral electrodes. An increase in temperature has a marginal effect on the interfacial ionic structures and molecular orientations of [P6,6,6,14][BMB] ionic species in a confined environment. Electrifying gold electrodes leads to peculiar changes in the interfacial ionic structures and molecular orientational arrangements of [P6,6,6,14] cations and [BMB] anions in negatively and positively charged gold electrodes, respectively. As surface charge density increases (but lower than 20 μC/cm2), the layer thickness of the mixed innermost interfacial layer gradually increases due to a consecutive accumulation of [P6,6,6,14] cations and [BMB] anions at negatively and positively charged electrodes, respectively, before the formation of distinct cationic and anionic innermost layers. Meanwhile, the molecular orientations of two oxalato rings in the same [BMB] anions change gradually from a parallel-perpendicular feature to being partially characterized by a tilted arrangement at an angle of 45° from the electrodes and finally to a dominant parallel coordination pattern along positively charged electrodes. Distinctive interfacial distribution patterns are also observed accordingly for phenyl rings that are directly connected to neighboring oxalato rings in [BMB] anions.
Collapse
Affiliation(s)
- Yong-Lei Wang
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University , SE-106 91 Stockholm, Sweden
| | - Mikhail Golets
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University , SE-106 91 Stockholm, Sweden
| | - Bin Li
- Theoretical Chemistry, Chemical Center, Lund University , P.O. Box 124, SE-221 00 Lund, Sweden
| | - Sten Sarman
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University , SE-106 91 Stockholm, Sweden
| | - Aatto Laaksonen
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University , SE-106 91 Stockholm, Sweden
| |
Collapse
|
34
|
Krämer G, Hausen F, Bennewitz R. Dynamic shear force microscopy of confined liquids at a gold electrode. Faraday Discuss 2017; 199:299-309. [DOI: 10.1039/c6fd00237d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The confinement of liquids in nanometer-scale gaps can lead to changes in their viscous shear properties. For liquids of polar molecules, the charge state of the confining surfaces has a significant influence on the structure in the confined liquid. Here we report on the implementation of dynamic shear force microscopy in an electrochemical cell. Lateral oscillations of the tip of an atomic force microscope were magnetically activated at a frequency of about 50 kHz. The damping of the lateral tip oscillation was recorded as a function of the tip–sample distance and of the electrode potential at the surface of a Au(100) single crystal electrode. The influence of surface charges on the shear response of the nano-confined liquids was demonstrated for the ionic liquid [EMIM][NTf2] and for aqueous Na2SO4 solution.
Collapse
Affiliation(s)
- Günther Krämer
- INM–Leibniz Insitute for New Materials and Physics Department
- Saarland University
- 66123 Saarbrücken
- Germany
| | - Florian Hausen
- Forschungszentrum Jülich
- Institute of Energy and Climate Research
- IEK-9
- 52425 Jülich
- Germany
| | - Roland Bennewitz
- INM–Leibniz Insitute for New Materials and Physics Department
- Saarland University
- 66123 Saarbrücken
- Germany
| |
Collapse
|
35
|
Affiliation(s)
- Shiguo Zhang
- College
of Materials Science and Engineering, Hunan University, Changsha 410082, China
- Center for Green Chemistry and Catalysis, State Key Laboratory for Oxo Synthesis & Selective Oxidation, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, No.18, Tianshui Middle Road, 730000 Lanzhou, China
| | - Jiaheng Zhang
- School
of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen 518055, China
| | - Yan Zhang
- College
of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Youquan Deng
- Center for Green Chemistry and Catalysis, State Key Laboratory for Oxo Synthesis & Selective Oxidation, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, No.18, Tianshui Middle Road, 730000 Lanzhou, China
| |
Collapse
|
36
|
Vatamanu J, Vatamanu M, Borodin O, Bedrov D. A comparative study of room temperature ionic liquids and their organic solvent mixtures near charged electrodes. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:464002. [PMID: 27623976 DOI: 10.1088/0953-8984/28/46/464002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The structural properties of electrolytes consisting of solutions of ionic liquids in a polar solvent at charged electrode surfaces are investigated using classical atomistic simulations. The studied electrolytes consisted of tetraethylammonium tetrafluoroborate (NEt4-BF4), 1-ethyl-3-methylimidazolium tetrafluoroborate (c2mim-BF4) and 1-octyl-3-methylimidazolium tetrafluoroborate (c8mim-BF4) salts dissolved in acetonitrile solvent. We discuss the influence of electrolyte concentration, chemical structure of the ionic salt, temperature, conducting versus semiconducting nature of the electrode, electrode geometry and surface roughness on the electric double layer structure and capacitance and compare these properties with those obtained for pure room temperature ionic liquids. We show that electrolytes consisting of solutions of ions can behave quite differently from pure ionic liquid electrolytes.
Collapse
Affiliation(s)
- Jenel Vatamanu
- University of Utah, MSE Department, Salt Lake City, UT 84112, USA
| | | | | | | |
Collapse
|
37
|
Zhong Y, Yan J, Li M, Chen L, Mao B. The Electric Double Layer in an Ionic Liquid Incorporated with Water Molecules: Atomic Force Microscopy Force Curve Study. ChemElectroChem 2016. [DOI: 10.1002/celc.201600177] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yunxin Zhong
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry; College of Chemistry and Chemical Engineering; Xiamen University; Xiamen 361005 China
| | - Jiawei Yan
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry; College of Chemistry and Chemical Engineering; Xiamen University; Xiamen 361005 China
| | - Miangang Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry; College of Chemistry and Chemical Engineering; Xiamen University; Xiamen 361005 China
| | - Li Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry; College of Chemistry and Chemical Engineering; Xiamen University; Xiamen 361005 China
| | - Bingwei Mao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry; College of Chemistry and Chemical Engineering; Xiamen University; Xiamen 361005 China
| |
Collapse
|
38
|
Liu G, Cai M, Wang X, Zhou F, Liu W. Magnetite-Loaded Thermosensitive Nanogels for Bioinspired Lubrication and Multimodal Friction Control. ACS Macro Lett 2016; 5:144-148. [PMID: 35668589 DOI: 10.1021/acsmacrolett.5b00860] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ability to control friction is quite attractive for many applications. Other than mechanical/physical methods to control friction, this letter shows how materials chemistry can regulate friction effectively. Magnetite-loaded thermosensitive poly(N-isopropylacrylamide) nanogels (Fe3O4@PNIPAM) were synthesized as nanoparticulate soft matter to reduce friction when it is used as an additive in aqueous lubricant. Interestingly, friction can be multiply regulated by temperature, magnetism, and near-infrared light through manipulating the colloidal properties of multifunctional composite nanogels in bulk solution and at the frictional interface.
Collapse
Affiliation(s)
- Guoqiang Liu
- State
Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical
Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Meirong Cai
- State
Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical
Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
| | - Xiaolong Wang
- State
Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical
Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
| | - Feng Zhou
- State
Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical
Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
| | - Weimin Liu
- State
Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical
Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
| |
Collapse
|
39
|
Govinda V, Venkatesu P, Bahadur I. Molecular interactions between ammonium-based ionic liquids and molecular solvents: current progress and challenges. Phys Chem Chem Phys 2016; 18:8278-326. [DOI: 10.1039/c6cp00199h] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this perspective, we describe how the thermodynamic parameters can be effectively used to gain valuable insights into molecular interactions between ammonium-based ILs and molecular solvents, which would be most useful in various industries.
Collapse
Affiliation(s)
- Varadhi Govinda
- Department of Chemistry
- University of Delhi
- Delhi – 110 007
- India
| | | | - Indra Bahadur
- Department of Chemistry and Material Science Innovation & Modelling (MaSIM) Research Focus Area
- Faculty of Agriculture
- Science and Technology
- North-West University (Mafikeng Campus)
- Mmabatho 2735
| |
Collapse
|
40
|
Iqbal S, Wezisla S, Podgaynyy N, Baltruschat H. Pyridine on Au(111): A frictional transition controlled by electrochemical potential. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
41
|
Fajardo OY, Bresme F, Kornyshev AA, Urbakh M. Electrotunable Friction with Ionic Liquid Lubricants: How Important Is the Molecular Structure of the Ions? J Phys Chem Lett 2015; 6:3998-4004. [PMID: 26722768 DOI: 10.1021/acs.jpclett.5b01802] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Using nonequilibrium molecular dynamics simulations and a coarse-grained model of ionic liquids, we have investigated the impact that the shape and the intramolecular charge distribution of the ions have on the electrotunable friction with ionic liquid nanoscale films. We show that the electric field induces significant structural changes in the film, leading to dramatic modifications of the friction force. Comparison of the present work with previous studies using different models of ionic liquids indicate that the phenomenology presented here applies to a wide range of ionic liquids. In particular, the electric-field-induced shift of the slippage plane from the solid-liquid interface to the interior of the film and the nonmonotonic variation of the friction force are common features of ionic lubricants under strong confinement. We also demonstrate that the molecular structure of the ions plays an important role in determining the electrostriction and electroswelling of the confined film, hence showing the importance of ion-specific effects in electrotunable friction.
Collapse
Affiliation(s)
- O Y Fajardo
- School of Chemistry, Tel Aviv University , 69978 Tel Aviv, Israel
| | - Fernando Bresme
- Deparment of Chemistry, Imperial College London , SW7 2AZ London, United Kingdom
| | - Alexei A Kornyshev
- Deparment of Chemistry, Imperial College London , SW7 2AZ London, United Kingdom
| | - Michael Urbakh
- School of Chemistry, Tel Aviv University , 69978 Tel Aviv, Israel
| |
Collapse
|
42
|
Abstract
Capacitive energy storage devices are receiving increasing experimental and theoretical attention due to their enormous potential for energy applications. Current research in this field is focused on the improvement of both the energy and the power density of supercapacitors by optimizing the nanostructure of porous electrodes and the chemical structure/composition of the electrolytes. However, the understanding of the underlying correlations and the mechanisms of electric double layer formation near charged surfaces and inside nanoporous electrodes is complicated by the complex interplay of several molecular scale phenomena. This Perspective presents several aspects regarding the experimental and theoretical research in the field, discusses the current atomistic and molecular scale understanding of the mechanisms of energy and charge storage, and provides a brief outlook to the future developments and applications of these devices.
Collapse
Affiliation(s)
- Jenel Vatamanu
- Department of Materials Science & Engineering, The University of Utah , 122 S. Central Campus Drive, Salt Lake City, Utah 84112, United States
| | - Dmitry Bedrov
- Department of Materials Science & Engineering, The University of Utah , 122 S. Central Campus Drive, Salt Lake City, Utah 84112, United States
| |
Collapse
|
43
|
Govinda V, Vasantha T, Khan I, Venkatesu P. Effect of the Alkyl Chain Length of the Cation on the Interactions between Water and Ammonium-Based Ionic Liquids: Experimental and COSMO-RS Studies. Ind Eng Chem Res 2015. [DOI: 10.1021/acs.iecr.5b01796] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Varadhi Govinda
- Department
of Chemistry, University of Delhi, Delhi 110 00 7, India
| | - T. Vasantha
- Department
of Chemistry, University of Delhi, Delhi 110 00 7, India
| | - Imran Khan
- CICECO,
Aveiro Institute of Materials, Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | | |
Collapse
|
44
|
Affiliation(s)
- Robert Hayes
- Discipline
of Chemistry, The University of Newcastle, NSW 2308, Callaghan, Australia
| | - Gregory G. Warr
- School
of Chemistry, The University of Sydney, NSW 2006, Sydney, Australia
| | - Rob Atkin
- Discipline
of Chemistry, The University of Newcastle, NSW 2308, Callaghan, Australia
| |
Collapse
|
45
|
Sweeney J, Webber GB, Atkin R. Near surface properties of mixtures of propylammonium nitrate with n-alkanols 2. Nanotribology and fluid dynamics. Phys Chem Chem Phys 2015; 17:26629-37. [DOI: 10.1039/c5cp04787k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Colloid probe friction force microscopy (FFM) has been used to study the lubricity of propylammonium nitrate (PAN) mixed with n-alkanols confined between sliding silica and mica surfaces.
Collapse
Affiliation(s)
- James Sweeney
- Centre for Advanced Particle Processing and Transport
- Newcastle Institute for Energy and Resources
- The University of Newcastle
- Callaghan
- Australia
| | - Grant B. Webber
- Centre for Advanced Particle Processing and Transport
- Newcastle Institute for Energy and Resources
- The University of Newcastle
- Callaghan
- Australia
| | - Rob Atkin
- Centre for Advanced Particle Processing and Transport
- Newcastle Institute for Energy and Resources
- The University of Newcastle
- Callaghan
- Australia
| |
Collapse
|
46
|
Li H, Atkin R, Page AJ. Combined friction force microscopy and quantum chemical investigation of the tribotronic response at the propylammonium nitrate–graphite interface. Phys Chem Chem Phys 2015; 17:16047-52. [DOI: 10.1039/c5cp01952d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The energetic origins of the variation in friction with potential at the propylammonium nitrate–graphite interface are revealed using friction force microscopy (FFM) in combination with quantum chemical simulations.
Collapse
Affiliation(s)
- H. Li
- Newcastle Institute for Energy and Resources
- The University of Newcastle
- Callaghan
- Australia
| | - R. Atkin
- Newcastle Institute for Energy and Resources
- The University of Newcastle
- Callaghan
- Australia
| | - A. J. Page
- Newcastle Institute for Energy and Resources
- The University of Newcastle
- Callaghan
- Australia
| |
Collapse
|
47
|
Salanne M. Simulations of room temperature ionic liquids: from polarizable to coarse-grained force fields. Phys Chem Chem Phys 2015; 17:14270-9. [DOI: 10.1039/c4cp05550k] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This perspective article summarizes the recent advances in the classical molecular modelling of room temperature ionic liquids.
Collapse
Affiliation(s)
- Mathieu Salanne
- Sorbonne Universités
- UPMC Univ Paris 06
- UMR 8234
- PHENIX
- F-75005 Paris
| |
Collapse
|