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Gatti SF, Gatti F, Amann T, Kailer A, Moser K, Weiss P, Seidel C, Rühe J. Tribological performance of electrically conductive and self-lubricating polypropylene-ionic-liquid composites. RSC Adv 2023; 13:8000-8014. [PMID: 36909746 PMCID: PMC9999252 DOI: 10.1039/d3ra00712j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/06/2023] [Indexed: 03/12/2023] Open
Abstract
In this work, self-lubricating and electrically conductive polymers on a polypropylene (PP) matrix were prepared and investigated. These properties were obtained by additivating PP with carbon black (CB) and multi-walled carbon nanotubes (MWCNTs), in combination with a surface active ionic liquid (IL, trihexyltetradecylphosphonium docusate [P66614][DOC]). These polymeric composites are expected to achieve coefficients of friction (COFs) comparable to lubricated systems. Combined with electrical conductivity, these materials could be applied in electrically loaded tribosystems. The COF was reduced by up to 25% compared to that of plain PP, and high electrical conductivity and self-lubrication were achieved. Fundamental differences between the carbon-based fillers in their interaction with IL were investigated with high-resolution surface analysis (TEM, AFM) and Raman and ATR-FTIR spectroscopy. By varying the tribological test parameters, the application limits of self-lubrication were identified. It was demonstrated that the contact pressure has a strong influence on the COF. Therefore, this work points to potential applications in (e.g. 3D-printed) bearings and electrically loaded bearings where electrical conductivity and relatively low COFs are required.
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Affiliation(s)
- Samuel Franz Gatti
- Fraunhofer Institute for Mechanics of Materials IWM, MicroTribology Center μTC Woehlerstraße 11 79108 Freiburg Germany .,Fraunhofer Cluster of Excellence Programmable Materials CPM Woehlerstraße 11 79108 Freiburg Germany
| | - Felix Gatti
- Fraunhofer Institute for Mechanics of Materials IWM, MicroTribology Center μTC Woehlerstraße 11 79108 Freiburg Germany .,Fraunhofer Cluster of Excellence Programmable Materials CPM Woehlerstraße 11 79108 Freiburg Germany
| | - Tobias Amann
- Fraunhofer Institute for Mechanics of Materials IWM, MicroTribology Center μTC Woehlerstraße 11 79108 Freiburg Germany .,Fraunhofer Cluster of Excellence Programmable Materials CPM Woehlerstraße 11 79108 Freiburg Germany
| | - Andreas Kailer
- Fraunhofer Institute for Mechanics of Materials IWM, MicroTribology Center μTC Woehlerstraße 11 79108 Freiburg Germany
| | - Kevin Moser
- Fraunhofer Cluster of Excellence Programmable Materials CPM Woehlerstraße 11 79108 Freiburg Germany.,Fraunhofer Institute for Chemical Technology ICT Joseph-von-Fraunhofer-Str. 7 76327 Pfinztal Germany
| | - Patrick Weiss
- Fraunhofer Institute for Chemical Technology ICT Joseph-von-Fraunhofer-Str. 7 76327 Pfinztal Germany
| | - Claudia Seidel
- Fraunhofer Institute for Chemical Technology ICT Joseph-von-Fraunhofer-Str. 7 76327 Pfinztal Germany
| | - Jürgen Rühe
- University Freiburg, IMTEK - Department of Microsystems Engineering Georges-Koehler-Allee 103 79110 Freiburg Germany
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2
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Seitzinger CL, Lodge TP. Impact of Photoactive Monomer Location in Photoresponsive Block Copolymer/Ionic Liquid Solutions. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c02113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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3
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Liu S, Li R, Tyagi M, Akcora P. Confinement Effects in Dynamics of Ionic Liquids with Polymer-Grafted Nanoparticles. Chemphyschem 2022; 23:e202200219. [PMID: 35676199 DOI: 10.1002/cphc.202200219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/07/2022] [Indexed: 11/07/2022]
Abstract
Ionic liquid mixed with poly(methyl methacrylate)-grafted nanoparticle aggregates at low particle concentrations was shown to exhibit different dynamics and ionic conductivity than that of pure ionic liquid in our previous studies. In this work, we report on the quasi-elastic neutron scattering results on ionic liquid containing polymer-grafted nanoparticles at the higher particle concentration. The diffusivity of imidazolium (HMIM + ) cations of 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIM-TFSI) in the presence of poly(methyl methacrylate)-grafted iron oxide nanoparticles and the ionic conductivity of solutions were discussed through the confinement. Analysis of the elastic incoherent structure factor suggested the confinement radius decreased with the addition of grafted particles in HMIM-TFSI/solvent mixture, indicating the confinement that is induced by the high concentration of grafted particles, shrinks the HMIM-TFSI restricted volume. We further conjecture that this enhanced diffusivity occurs as a result of the local ordering of cations within aggregates of poly(methyl methacrylate)-grafted particles.
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Affiliation(s)
- Siqi Liu
- 1 Castle Point on Hudson, Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, McLean Hall 415, 07030, Hoboken, NJ, USA
| | - Ruhao Li
- 1 Castle Point on Hudson, Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, McLean Hall 415, 07030, Hoboken, NJ, USA
| | - Madhusudan Tyagi
- NIST Center for Neutron Research, 100 Bureau Dr, 20899, Gaithersburg, MD, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, 20742, Maryland, MD, USA
| | - Pinar Akcora
- 1 Castle Point on Hudson, Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, McLean Hall 415, 07030, Hoboken, NJ, USA
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4
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Stephens NM, Masching HP, Walid MKI, Petrich JW, Anderson JL, Smith EA. Temperature-Dependent Constrained Diffusion of Micro-Confined Alkylimidazolium Chloride Ionic Liquids. J Phys Chem B 2022; 126:4324-4333. [PMID: 35649257 DOI: 10.1021/acs.jpcb.2c01588] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alkylimidazolium chloride ionic liquids (ILs) have many uses in a variety of separation systems, including micro-confined separation systems. To understand the separation mechanism in these systems, the diffusion properties of analytes in ILs under relevant operating conditions, including micro-confinement dimension and temperature, should be known. For example, separation efficiencies for various IL-based microextraction techniques are dependent on the sample volume and temperature. Temperature-dependent (20-100 °C) fluorescence recovery after photobleaching (FRAP) was utilized to determine the diffusion properties of a zwitterionic, hydrophilic dye, ATTO 647, in alkylimidazolium chloride ILs in micro-confined geometries. These micro-confined geometries were generated by sandwiching the IL between glass substrates that were separated by ∼1 to 100 μm. From the measured temperature-dependent FRAP data, we note alkyl chain length-, thickness-, and temperature-dependent diffusion coefficients, with values ranging from 0.021 to 46 μm2/s. Deviations from Brownian diffusion are observed at lower temperatures and increasingly less so at elevated temperatures; the differences are attributed to alterations in intermolecular interactions that reduce temperature-dependent nanoscale structural heterogeneities. The temperature- and thickness-dependent data provide a useful foundation for efficient design of micro-confined IL separation systems.
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Affiliation(s)
- Nicole M Stephens
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011-3111, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
| | - Hayley P Masching
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011-3111, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
| | - Mohammad K I Walid
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
| | - Jacob W Petrich
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011-3111, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
| | - Jared L Anderson
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011-3111, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
| | - Emily A Smith
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011-3111, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
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5
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Seitzinger CL, Hall CC, Lodge TP. Photoreversible Order–Disorder Transitions in Block Copolymer/Ionic Liquid Solutions. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Claire L. Seitzinger
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Cecilia C. Hall
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Timothy P. Lodge
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
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6
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Kodis G, Ertem MZ, Newton MD, Matyushov DV. Reorganization Energy of Electron Transfer in Ionic Liquids. J Phys Chem Lett 2022; 13:3297-3303. [PMID: 35389644 DOI: 10.1021/acs.jpclett.2c00733] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Bandshape analysis of charge-transfer optical bands in room-temperature ionic liquids (ILs) was performed to extract the reorganization energy of electron transfer. Remarkably, the reorganization energies in ILs are close to those in cyclohexane. This result runs against common wisdom in the field since conducting ILs, which are characterized by an infinite static dielectric constant, and nonpolar cyclohexane fall to the opposite ends of the polarity scale based on their dielectric constants. Theoretical calculations employing structure factors of ILs from molecular dynamics simulations support the low values of the reorganization energy. Standard dielectric arguments do not apply to solvation in ILs, and nonergodic reorganization energies are required for a quantitative analysis.
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Affiliation(s)
- Gerdenis Kodis
- Department of Physics and School of Molecular Sciences, Arizona State University, PO Box 871504, Tempe, Arizona 85287-1504, United States
| | - Mehmed Z Ertem
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Marshall D Newton
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Dmitry V Matyushov
- Department of Physics and School of Molecular Sciences, Arizona State University, PO Box 871504, Tempe, Arizona 85287-1504, United States
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Qu M, Li S, Chen J, Xiao Y, Xiao J. Ion Transport in the EMITFSI/PVDF System at Different Temperatures: A Molecular Dynamics Simulation. ACS OMEGA 2022; 7:9333-9342. [PMID: 35356691 PMCID: PMC8945056 DOI: 10.1021/acsomega.1c06160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/02/2022] [Indexed: 05/13/2023]
Abstract
We used all-atom molecular dynamics simulations to study the ion transport in the 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide/poly(vinylidene fluoride) (EMITFSI/PVDF) system with 40.05 wt % EMITFSI at different temperatures. The glass-transition temperature (T g = 204 K) of this system shows a good agreement with the experimental value (200 K). With the increase of temperature, the peaks of the pair correlation function show an increasing trend. Interestingly, the coordination numbers of ion pairs and the degree of independent ion motion are mainly affected by the binding energy between ion pairs as the temperature increases. In addition, the ion transport properties with increasing temperature can be studied by the ion-pair relaxation times, ion-pair lifetimes, and diffusion coefficients. The simulation results illustrate that the ion transport is intensified. Especially, the cations can always diffuse faster than the anions. The power law shows that mobilities of anions and cations are seen to exhibit a "superionic" behavior. With the increase of temperature, transference numbers of anions decrease first and then increase and transference numbers of cations show the opposite changes; ionic conductivity increases gradually; and viscosity decreases gradually, indicating that the diffusion resistance of ions decreases. In general, after adding PVDF into the EMITFSI system, the glass-transition temperature and viscosity increase, the ionic conductivity and degree of independent ion motion decrease, and diffusion coefficients of cations decrease faster than those of the anions.
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Affiliation(s)
- Minghe Qu
- Molecules
and Materials Computation Institute, School of Chemistry and Chemical
Engineering, Nanjing University of Science
and Technology, Nanjing 210094, P. R. China
| | - Shenshen Li
- Molecules
and Materials Computation Institute, School of Chemistry and Chemical
Engineering, Nanjing University of Science
and Technology, Nanjing 210094, P. R. China
| | - Jian Chen
- Chuannan
Machinery Manufacturing Plant, Luzhou 646000, P. R. China
| | - Yunqin Xiao
- Molecules
and Materials Computation Institute, School of Chemistry and Chemical
Engineering, Nanjing University of Science
and Technology, Nanjing 210094, P. R. China
- Science
and Technology on Aerospace Chemical Power Laboratory, Hubei Institute of Aerospace Chemical Technology, Xiangyang 441003, P. R. China
| | - Jijun Xiao
- Molecules
and Materials Computation Institute, School of Chemistry and Chemical
Engineering, Nanjing University of Science
and Technology, Nanjing 210094, P. R. China
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8
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The charge transport mechanism in Brønsted-acidic protic ionic liquid/water systems – An NMR and QENS study. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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9
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Kubisiak P, Wróbel P, Eilmes A. How Temperature, Pressure, and Salt Concentration Affect Correlations in LiTFSI/EMIM-TFSI Electrolytes: A Molecular Dynamics Study. J Phys Chem B 2021; 125:12292-12302. [PMID: 34706539 PMCID: PMC8591607 DOI: 10.1021/acs.jpcb.1c07782] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/13/2021] [Indexed: 11/29/2022]
Abstract
Classical polarizable molecular dynamics simulations have been performed for LiTFSI solutions in the EMIM-TFSI ionic liquid. Different temperature or pressure values and salt concentrations have been examined. The structure and dynamics of the solvation shell of Li+ cations, diffusion coefficients of ions, conductivities of the electrolytes, and correlations between motions of ions have been analyzed. The results indicated that regardless of the conditions, significant correlations are present in all systems. The degree of correlations depends mainly on the salt fraction in the electrolyte and is much less affected by temperature and pressure changes. A positive correlation between motions of Li+ cations and TFSI anions, leading to the occurrence of negative Li+ transference numbers, exists for all conditions, although temperature and pressure changes affect the speed of anion exchange in Li+ solvation shells.
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Affiliation(s)
- Piotr Kubisiak
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Piotr Wróbel
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Andrzej Eilmes
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
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10
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Knudsen PA, Niss K, Bailey NP. Quantifying dynamical and structural invariance in a simple molten salt model. J Chem Phys 2021; 155:054506. [PMID: 34364358 DOI: 10.1063/5.0055794] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent experimental results for the structure in the ionic liquid PYR14 +TFSI- have shown invariance in the main structure factor peak along curves of equal electrical conductivity [Hansen et al., Phys. Chem. Chem. Phys. 22, 14169 (2020)]. The charge peak decreases slightly with increasing temperature at fixed conductivity, however. For simple liquids, curves with invariant dynamics and structure, known as isomorphs, can be identified as configurational adiabats. While liquids with strong-Coulomb interactions do not have good isomorphs, ionic liquids could be an intermediate case with approximate isomorphs along which some aspects of structure and dynamics are invariant. We study a simple molten salt model using molecular dynamics simulations to test this hypothesis. Simple measures of structure and dynamics are investigated along with one transport property, the shear viscosity. We find that there is a substantial degree of invariance of the self-intermediate scattering function, the mean square displacement, and the viscosity along configurational adiabats over a wide range of densities for the three adiabats simulated. The density range studied is more than a factor of two and extends from the strong-Coulomb regime at low densities to the weak-Coulomb regime at high densities. The structure is not invariant over the full range of density, but in the weak-Coulomb regime, we see behavior similar to that seen experimentally over density changes of order 15%. In view of the limited structural invariance but substantial dynamical invariance, we designate the configurational adiabats as isodynes.
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Affiliation(s)
- Peter A Knudsen
- Glass and Time, IMFUFA, Department of Science and Environment, Roskilde University, P.O. Box 260, Roskilde DK-4000, Denmark
| | - Kristine Niss
- Glass and Time, IMFUFA, Department of Science and Environment, Roskilde University, P.O. Box 260, Roskilde DK-4000, Denmark
| | - Nicholas P Bailey
- Glass and Time, IMFUFA, Department of Science and Environment, Roskilde University, P.O. Box 260, Roskilde DK-4000, Denmark
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Lundin F, Aguilera L, Hansen HW, Lages S, Labrador A, Niss K, Frick B, Matic A. Structure and dynamics of highly concentrated LiTFSI/acetonitrile electrolytes. Phys Chem Chem Phys 2021; 23:13819-13826. [PMID: 34195732 DOI: 10.1039/d1cp02006d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High salt concentration has been shown to induce increased electrochemical stability in organic solvent-based electrolytes. Accompanying the change in bulk properties is a structural ordering on mesoscopic length scales and changes in the ion transport mechanism have also been suggested. Here we investigate the local structure and dynamics in highly concentrated acetonitrile electrolytes as a function of salt concentration. Already at low concentrations ordering on microscopic length scales in the electrolytes is revealed by small angle X-ray scattering, as a result of correlations of Li+ coordinating clusters. For higher salt concentrations a charge alternation-like ordering is found as anions start to take part in the solvation. Results from quasi-elastic neutron spectroscopy reveal a jump diffusion dynamical process with jump lengths virtually independent of both temperature and Li-salt concentration. The jump can be envisaged as dissociation of a solvent molecule or anion from a particular Li+ solvation structure. The residence time, 50-800 ps, between the jumps is found to be highly temperature and Li-salt concentration dependent, with shorter residence times for higher temperature and lower concentrations. The increased residence time at high Li-salt concentration can be attributed to changes in the interaction of the solvation shell as a larger fraction of TFSI anions take part in the solvation, forming more stable solvation shells.
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Affiliation(s)
- Filippa Lundin
- Department of Physics, Materials Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden.
| | - Luis Aguilera
- Department of Physics, Materials Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden. and Energy and Installation, Volvo Cars Corporation, Göteborg, Sweden
| | - Henriette Wase Hansen
- Department of Physics, Materials Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden. and Glass and Time, IMUFA, Department of Science and Environment, Roskilde University, Postbox 260, DK-4000 Roskilde, Denmark and Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France
| | - Sebastian Lages
- Department of Physics, Materials Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden. and MaxIV Laboratory, Fotongatan 2, SE 224 84 Lund, Sweden
| | - Ana Labrador
- MaxIV Laboratory, Fotongatan 2, SE 224 84 Lund, Sweden
| | - Kristine Niss
- Glass and Time, IMUFA, Department of Science and Environment, Roskilde University, Postbox 260, DK-4000 Roskilde, Denmark
| | - Bernhard Frick
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France
| | - Aleksandar Matic
- Department of Physics, Materials Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden.
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