1
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Pontoni D, DiMichiel M, Murphy BM, Honkimäki V, Deutsch M. Ordering of ionic liquids at a charged sapphire interface: Evolution with cationic chain length. J Colloid Interface Sci 2024; 661:33-45. [PMID: 38295701 DOI: 10.1016/j.jcis.2024.01.126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/09/2024] [Accepted: 01/18/2024] [Indexed: 02/27/2024]
Abstract
HYPOTHESIS Room Temperature Ionic Liquids (RTILs) bulk's molecular layering dominates their structure also at the RTIL/sapphire interface, increasing the layer spacing with the cationic alkyl chain length n. However, the negatively-charged sapphire surface compresses the layers, increases the layering range, and affects the intra-layer structure in yet unknown ways. EXPERIMENTS X-ray reflectivity (XR) off the RTIL/sapphire interface, for a broad homologous RTIL series 1-alkyl-3-methylimidazolium bis(trifluoromethansulfonyl)imide, hitherto unavailable for any RTIL. FINDINGS RTIL layers against the sapphire, exhibit two spacings: da and db. da is n-varying, follows the behavior of the bulk spacing but exhibits a downshift, thus showing significant layer compression, and over twofold polar slab thinning. The latter suggests exclusion of anions from the interfacial region due to the negative sapphire charging by x-ray-released electrons. The layering range is larger than the bulk's. db is short and near n-independent, suggesting polar moieties' layering, the coexistence mode of which with the da-spaced layering is unclear. Comparing the present layering with the bulk's and the RTIL/air interface's provides insight into the Coulomb and dispersion interaction balance dominating the RTIL's structure and the impact thereon of the presence of a charged solid interface.
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Affiliation(s)
- Diego Pontoni
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Marco DiMichiel
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Bridget M Murphy
- Institute of Experimental and Applied Physics, Kiel University, Kiel D-24098, Germany; Ruprecht-Haensel Laboratory, Kiel University, Kiel D-24118, Germany
| | - Veijo Honkimäki
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Moshe Deutsch
- Physics Dept. & Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel.
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2
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Konovalov O, Rein V, Saedi M, Groot IMN, Renaud G, Jankowski M. Tripling of the scattering vector range of X-ray reflectivity on liquid surfaces using a double-crystal deflector. J Appl Crystallogr 2024; 57:258-265. [PMID: 38596733 PMCID: PMC11001415 DOI: 10.1107/s1600576724000657] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 01/18/2024] [Indexed: 04/11/2024] Open
Abstract
The maximum range of perpendicular momentum transfer (q z) has been tripled for X-ray scattering from liquid surfaces when using a double-crystal deflector setup to tilt the incident X-ray beam. This is achieved by employing a higher-energy X-ray beam to access Miller indices of reflecting crystal atomic planes that are three times higher than usual. The deviation from the exact Bragg angle condition induced by misalignment between the X-ray beam axis and the main rotation axis of the double-crystal deflector is calculated, and a fast and straightforward procedure to align them is deduced. An experimental method of measuring scattering intensity along the q z direction on liquid surfaces up to q z = 7 Å-1 is presented, with liquid copper serving as a reference system for benchmarking purposes.
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Affiliation(s)
- Oleg Konovalov
- European Synchrotron Radiation Facility–ESRF, 71 Avenue des Martyrs, CS 40220, 38043 Grenoble Cedex 9, France
| | - Valentina Rein
- European Synchrotron Radiation Facility–ESRF, 71 Avenue des Martyrs, CS 40220, 38043 Grenoble Cedex 9, France
- Univ. Grenoble Alpes, CEA, IRIG/MEM/NR, 38000 Grenoble, France
| | - Mehdi Saedi
- Physics Department, Shahid Beheshti University, 1983969411 Tehran, Iran
| | - Irene M. N. Groot
- Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Gilles Renaud
- Univ. Grenoble Alpes, CEA, IRIG/MEM/NR, 38000 Grenoble, France
| | - Maciej Jankowski
- European Synchrotron Radiation Facility–ESRF, 71 Avenue des Martyrs, CS 40220, 38043 Grenoble Cedex 9, France
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3
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Men H. A molecular dynamics study on the boundary between homogeneous and heterogeneous nucleation. J Chem Phys 2024; 160:094702. [PMID: 38426521 DOI: 10.1063/5.0192069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 02/17/2024] [Indexed: 03/02/2024] Open
Abstract
The large discrepancy among the nucleation kinetics extracted from experimental measurements and computer simulations and the prediction of the classical nucleation theory (CNT) has stimulated intense arguments about its origin in the past decades, which is crucially relevant to the validity of the CNT. In this paper, we investigate the atomistic mechanism of the nucleation in liquid Al in contact with amorphous substrates with atomic-level smooth/rough surfaces, using molecular dynamics (MD) simulations. This study reveals that the slightly distorted local fcc/hcp structures in amorphous substrates with smooth surfaces can promote heterogeneous nucleation through a structural templating mechanism, and on the other hand, homogeneous nucleation will occur at a larger undercooling through a fluctuation mechanism if the surface is rough. Thus, some impurities, previously thought to be impotent, could be activated in the homogeneous nucleation experiments. We further find that the initial growth of the nucleus on smooth surfaces of amorphous substrates is one order of magnitude faster than that in homogeneous nucleation. Both these factors could significantly contribute to the discrepancy in the nucleation kinetics. This study is also supported by a recent study of the synthesis of high-entropy alloy nanoparticles assisted with the liquid metal Ga [Cao et al., Nature 619, 73 (2023)]. In this study, we established that the boundary existed between homogeneous and heterogeneous nucleation, i.e., the structural templating is a general mechanism for heterogeneous nucleation, and in its absence, homogeneous nucleation will occur through the fluctuation mechanism. This study provides an in-depth understanding of the nucleation theory and experiments.
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Affiliation(s)
- Hua Men
- BCAST, Brunel University London, Uxbridge, Middlesex UB8 3PH, United Kingdom
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4
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Magnussen OM, Drnec J, Qiu C, Martens I, Huang JJ, Chattot R, Singer A. In Situ and Operando X-ray Scattering Methods in Electrochemistry and Electrocatalysis. Chem Rev 2024; 124:629-721. [PMID: 38253355 PMCID: PMC10870989 DOI: 10.1021/acs.chemrev.3c00331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 10/02/2023] [Accepted: 11/13/2023] [Indexed: 01/24/2024]
Abstract
Electrochemical and electrocatalytic processes are of key importance for the transition to a sustainable energy supply as well as for a wide variety of other technologically relevant fields. Further development of these processes requires in-depth understanding of the atomic, nano, and micro scale structure of the materials and interfaces in electrochemical devices under reaction conditions. We here provide a comprehensive review of in situ and operando studies by X-ray scattering methods, which are powerful and highly versatile tools to provide such understanding. We discuss the application of X-ray scattering to a wide variety of electrochemical systems, ranging from metal and oxide single crystals to nanoparticles and even full devices. We show how structural data on bulk phases, electrode-electrolyte interfaces, and nanoscale morphology can be obtained and describe recent developments that provide highly local information and insight into the composition and electronic structure. These X-ray scattering studies yield insights into the structure in the double layer potential range as well as into the structural evolution during electrocatalytic processes and phase formation reactions, such as nucleation and growth during electrodeposition and dissolution, the formation of passive films, corrosion processes, and the electrochemical intercalation into battery materials.
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Affiliation(s)
- Olaf M. Magnussen
- Kiel
University, Institute of Experimental and
Applied Physics, 24098 Kiel, Germany
- Ruprecht-Haensel
Laboratory, Kiel University, 24118 Kiel, Germany
| | - Jakub Drnec
- ESRF,
Experiments Division, 38000 Grenoble, France
| | - Canrong Qiu
- Kiel
University, Institute of Experimental and
Applied Physics, 24098 Kiel, Germany
| | | | - Jason J. Huang
- Department
of Materials Science and Engineering, Cornell
University, Ithaca, New York 14853, United States
| | - Raphaël Chattot
- ICGM,
Univ. Montpellier, CNRS, ENSCM, 34095 Montpellier Cedex 5, France
| | - Andrej Singer
- Department
of Materials Science and Engineering, Cornell
University, Ithaca, New York 14853, United States
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5
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Hazelnis JP, Maldonado S. Electrosynthesis of Quasi-Epitaxial Crystals on Liquid Metals. J Am Chem Soc 2023; 145:27616-27625. [PMID: 38051913 DOI: 10.1021/jacs.3c09455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Electrosynthesis of single-crystalline metallic and intermetallic particles with a preferred orientation onto liquid metal electrodes has been performed. Liquid gallium electrodes immersed in aqueous alkaline electrolytes without any molecular additive or external solid seeding substrates were used to electroreduce separately Pb2+, Bi3+, Pd2+, and Mn2+. The crystallinity, composition, and orientation of the electrodeposition products were characterized by using scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, grazing incidence X-ray diffraction, and energy-dispersive X-ray spectroscopy. Electrodeposition of Pb and Bi results in the incipient formation of two-dimensional (2D) nuclei that subsequently direct the growth of Pb and Bi single crystals along the most close-packed [111] and [0001] directions, respectively. The absence of any intervening surface oxides and a low electroreduction flux are necessary to avoid polycrystalline dendrite formation. Under comparable conditions, the electrodeposition of Pd and Mn results in single-crystalline intermetallic particles at the interface. Each crystal exhibits a preferred orientation consistent with the unique atomic packing of the near-surface region of the liquid Ga. The presented study suggests a new concept in electrodeposition processes where the liquid metal structure imparts quasi-epitaxial growth in a system in which the electrode material specifically has no crystallinity or long-range order. This study is thus the first demonstration of highly oriented electrodeposition at a liquid/liquid interface under ambient conditions, highlighting the unique solvation environment of liquid metal interfaces for forming thin metallic and intermetallic films.
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Affiliation(s)
- Joshua P Hazelnis
- Department of Chemistry University of Michigan, 930 North University, Ann Arbor, Michigan 48109-1055, United States
| | - Stephen Maldonado
- Department of Chemistry University of Michigan, 930 North University, Ann Arbor, Michigan 48109-1055, United States
- Program in Applied Physics, University of Michigan, 2477 Randall Laboratory, Ann Arbor, Michigan 48109-1040, United States
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6
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Wang D, Lippmann M, Gäding J, Ehnes A, Novikov D, Meißner R, Seeck OH. Orientation order of a nonpolar molecular fluid compressed into a nanosmall space. NANOSCALE 2023; 15:8019-8028. [PMID: 37070420 DOI: 10.1039/d2nr06330a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The ordering structures of non-polar carbon tetrachloride liquid compressed to nano-scales between parallel substrates is studied in this work. The theoretical considerations show that the potential well formed by the confined parallel substrates induces orientational ordering of non-polar molecules. Through molecular dynamic (MD) simulations, the relations between various ordered structures of a non-polar liquid (carbon tetrachloride) and the confined gap size are demonstrated. The density distribution shows that the confinement does affect the ordering modes and induces an orientational ordering of molecules at the solid-liquid interface under extreme confinement conditions. This molecular orientation suggested from the theoretical model and MD simulation is directly supported by the experimental studies for the first time. The X-ray reflectivity data reveal a strong layering effect with splitting of the density profile in C and Cl-rich sublayers. The investigation shows that the liquid structure factor in confinement has a characteristic length similar to the short-range ordering in bulk, but the confined structure is strongly influenced by the surface potential and the interface properties. This introduces preferred molecular orientation and ordering which are not favorable in the bulk phase. As the orientational ordering is closely related to crystallization, our results provide a new perspective to control the crystallization in nano-confined space by compression.
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Affiliation(s)
- Dan Wang
- State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, No. 29 Yudao Street, Nanjing 210016, China
| | - Milena Lippmann
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
| | | | - Anita Ehnes
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
| | - Dmitri Novikov
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
| | - Robert Meißner
- Hamburg University of Technology, 21073 Hamburg, Germany
- Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany
| | - Oliver H Seeck
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
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7
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Sartori A, Giri RP, Fujii H, Hövelmann SC, Warias JE, Jordt P, Shen C, Murphy BM, Magnussen OM. Role of chemisorbing species in growth at liquid metal-electrolyte interfaces revealed by in situ X-ray scattering. Nat Commun 2022; 13:5421. [PMID: 36109498 PMCID: PMC9477831 DOI: 10.1038/s41467-022-32932-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/22/2022] [Indexed: 11/22/2022] Open
Abstract
Liquid-liquid interfaces offer intriguing possibilities for nanomaterials growth. Here, fundamental interface-related mechanisms that control the growth behavior in these systems are studied for Pb halide formation at the interface between NaX + PbX2 (X = F, Cl, Br) and liquid Hg electrodes using in situ X-ray scattering and complementary electrochemical and microscopy measurements. These studies reveal a decisive role of the halide species in nucleation and growth of these compounds. In Cl- and Br-containing solution, deposition starts by rapid formation of well-defined ultrathin (∼7 Å) precursor adlayers, which provide a structural template for the subsequent quasi-epitaxial growth of c-axis oriented Pb(OH)X bulk crystals. In contrast, growth in F-containing solution proceeds by slow formation of a more disordered deposit, resulting in random bulk crystal orientations on the Hg surface. These differences can be assigned to the interface chemistry, specifically halide chemisorption, which steers the formation of these highly textured deposits at the liquid-liquid interface. Growth at liquid-liquid interfaces differ inherently from that on solids, making it attractive for nanomaterial formation. Here, the authors use X-ray scattering to derive a detailed microscopic picture of lead-halide growth on liquid mercury that reveals the key importance of anion adsorption.
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8
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Yao X, Liu Q, Wang B, Yu J, Aristov MM, Shi C, Zhang GGZ, Yu L. Anisotropic Molecular Organization at a Liquid/Vapor Interface Promotes Crystal Nucleation with Polymorph Selection. J Am Chem Soc 2022; 144:11638-11645. [PMID: 35735940 DOI: 10.1021/jacs.2c02623] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The molecules at the surface of a liquid have different organization and dynamics from those in the bulk, potentially altering the rate of crystal nucleation and polymorphic selection, but this effect remains poorly understood. Here we demonstrate that nucleation at the surface of a pure liquid, d-arabitol, is vastly enhanced, by 12 orders of magnitude, and selects a different polymorph. The surface effect intensifies with cooling and can be inhibited by a dilute, surface-active second component. This phenomenon arises from the anisotropic molecular packing at the interface and its similarity to the surface-nucleating polymorph. Our finding is relevant for controlling the crystallization and polymorphism in any system with a significant interface such as nanodroplets and atmospheric water.
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Affiliation(s)
- Xin Yao
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Qitong Liu
- Civil & Environmental Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Bu Wang
- Civil & Environmental Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Junguang Yu
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Michael M Aristov
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Chenyang Shi
- Drug Product Development, Research and Development, AbbVie Inc., North Chicago, Illinois 60064, United States
| | - Geoff G Z Zhang
- Drug Product Development, Research and Development, AbbVie Inc., North Chicago, Illinois 60064, United States
| | - Lian Yu
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States.,Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
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9
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Konovalov OV, Belova V, La Porta F, Saedi M, Groot IMN, Renaud G, Snigireva I, Snigirev A, Voevodina M, Shen C, Sartori A, Murphy BM, Jankowski M. X-ray reflectivity from curved surfaces as illustrated by a graphene layer on molten copper. JOURNAL OF SYNCHROTRON RADIATION 2022; 29:711-720. [PMID: 35511004 PMCID: PMC9070704 DOI: 10.1107/s1600577522002053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
The X-ray reflectivity technique can provide out-of-plane electron-density profiles of surfaces, interfaces, and thin films, with atomic resolution accuracy. While current methodologies require high surface flatness, this becomes challenging for naturally curved surfaces, particularly for liquid metals, due to the very high surface tension. Here, the development of X-ray reflectivity measurements with beam sizes of a few tens of micrometres on highly curved liquid surfaces using a synchrotron diffractometer equipped with a double crystal beam deflector is presented. The proposed and developed method, which uses a standard reflectivity θ-2θ scan, is successfully applied to study in situ the bare surface of molten copper and molten copper covered by a graphene layer grown in situ by chemical vapor deposition. It was found that the roughness of the bare liquid surface of copper at 1400 K is 1.25 ± 0.10 Å, while the graphene layer is separated from the liquid surface by a distance of 1.55 ± 0.08 Å and has a roughness of 1.26 ± 0.09 Å.
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Affiliation(s)
- Oleg V. Konovalov
- ESRF – The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Valentina Belova
- ESRF – The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Francesco La Porta
- ESRF – The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Mehdi Saedi
- Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Irene M. N. Groot
- Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Gilles Renaud
- Univ. Grenoble Alpes, CEA, IRIG/MEM/NRS, 38000 Grenoble, France
| | - Irina Snigireva
- ESRF – The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Anatoly Snigirev
- Immanuel Kant Baltic Federal University, 14 Nevskogo, 236041 Kaliningrad, Russian Federation
| | - Maria Voevodina
- Immanuel Kant Baltic Federal University, 14 Nevskogo, 236041 Kaliningrad, Russian Federation
| | - Chen Shen
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Andrea Sartori
- Institute for Experimental and Applied Physics, Kiel University, Olshausenstrasse 40, 24098 Kiel, Germany
| | - Bridget M. Murphy
- Institute for Experimental and Applied Physics, Kiel University, Olshausenstrasse 40, 24098 Kiel, Germany
- Ruprecht-Haensel Laboratory, Kiel University, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
| | - Maciej Jankowski
- ESRF – The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
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10
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Kana N, Morad R, Akbari M, Henini M, Niemela J, Hacque F, Gibaud A, Maaza M. Mercury goes Solid at room temperature at nanoscale and a potential Hg waste storage. Sci Rep 2022; 12:3494. [PMID: 35241681 PMCID: PMC8894422 DOI: 10.1038/s41598-022-06857-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 01/27/2022] [Indexed: 11/09/2022] Open
Abstract
While room temperature bulk mercury is liquid, it is solid in its nano-configuration (Ønano-Hg ≤ 2.5 nm). Conjugating the nano-scale size effect and the Laplace driven surface excess pressure, Hg nanoparticles of Ønano-Hg ≤ 2.4 nm embedded in a 2-D turbostratic Boron Nitride (BN) host matrix exhibited a net crystallization at room temperature via the experimentally observed (101) and (003) diffraction Bragg peaks of the solid Hg rhombohedral α-phase. The observed crystallization is correlated to a surface atomic ordering of 7 to 8 reticular atomic plans of the rhombohedral α-phase. Such a novelty of size effect on phase transition phenomena in Hg is conjugated to a potential Hg waste storage technology. Considering the vapor pressure of bulk Hg, Room Temperature (RT) Solid nano-Hg confinement could represent a potential green approach of Hg waste storage derived from modern halogen efficient light technology.
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Affiliation(s)
- N Kana
- UNESCO-UNISA-iTLABS/NRF Africa Chair in Nano-Sciences and Nanotechnology, CGS, University of South Africa, Muckleneuk ridge, Pretoria, 0001, South Africa.
- NANOAFNET, iThemba LABS-National Research Foundation of South Africa, 1 Old Faure Road, Western Cape, 7129, South Africa.
| | - R Morad
- UNESCO-UNISA-iTLABS/NRF Africa Chair in Nano-Sciences and Nanotechnology, CGS, University of South Africa, Muckleneuk ridge, Pretoria, 0001, South Africa
- NANOAFNET, iThemba LABS-National Research Foundation of South Africa, 1 Old Faure Road, Western Cape, 7129, South Africa
| | - M Akbari
- UNESCO-UNISA-iTLABS/NRF Africa Chair in Nano-Sciences and Nanotechnology, CGS, University of South Africa, Muckleneuk ridge, Pretoria, 0001, South Africa
- NANOAFNET, iThemba LABS-National Research Foundation of South Africa, 1 Old Faure Road, Western Cape, 7129, South Africa
| | - M Henini
- UNESCO-UNISA-iTLABS/NRF Africa Chair in Nano-Sciences and Nanotechnology, CGS, University of South Africa, Muckleneuk ridge, Pretoria, 0001, South Africa
- NANOAFNET, iThemba LABS-National Research Foundation of South Africa, 1 Old Faure Road, Western Cape, 7129, South Africa
- Physics and Astronomy Department, Nottingham University, Nottingham, NG7 2RD7, UK
| | - J Niemela
- International Centre for Theoretical Physics (ICTP), Str. Costiera, 11, 34151, Trieste, Italy
| | - F Hacque
- UNESCO-UNISA-iTLABS/NRF Africa Chair in Nano-Sciences and Nanotechnology, CGS, University of South Africa, Muckleneuk ridge, Pretoria, 0001, South Africa
- NANOAFNET, iThemba LABS-National Research Foundation of South Africa, 1 Old Faure Road, Western Cape, 7129, South Africa
- Physics Department, Rajshahi University, Dakha, Bangladesh
| | - A Gibaud
- UNESCO-UNISA-iTLABS/NRF Africa Chair in Nano-Sciences and Nanotechnology, CGS, University of South Africa, Muckleneuk ridge, Pretoria, 0001, South Africa
- NANOAFNET, iThemba LABS-National Research Foundation of South Africa, 1 Old Faure Road, Western Cape, 7129, South Africa
- IMMM, UMR 6283 CNRS, University of Le Maine, Bd O. Messiaen, 72085, Le Mans cedex 09, France
| | - M Maaza
- UNESCO-UNISA-iTLABS/NRF Africa Chair in Nano-Sciences and Nanotechnology, CGS, University of South Africa, Muckleneuk ridge, Pretoria, 0001, South Africa.
- NANOAFNET, iThemba LABS-National Research Foundation of South Africa, 1 Old Faure Road, Western Cape, 7129, South Africa.
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11
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Deutsch M, Magnussen OM, Haddad J, Pontoni D, Murphy BM, Ocko BM. Comment on "Bi-layering at ionic liquid surfaces: a sum - frequency generation vibrational spectroscopy - and molecular dynamics simulation-based study" by T. Iwahashi, T. Ishiyama, Y. Sakai, A. Morita, D. Kim and Y. Ouchi, Phys. Chem. Chem. Phys., 2020, 22, 12565. Phys Chem Chem Phys 2021; 23:5020-5027. [PMID: 33595568 DOI: 10.1039/d0cp04882h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This Comment raises several questions concerning the surface structure concluded in the paper referenced in the title. Specifically, that paper ignores previous experiments and simulations which demonstrate for the same ionic liquids depth-decaying, multilayered surface-normal density profiles rather than the claimed molecular mono- or bi-layers. We demonstrate that the claimed structure does not reproduce the measured X-ray reflectivity, which probes directly the surface-normal density profile. The measured reflectivities are found, however, to be well-reproduced by a multilayered density model. These results, and previous experimental and simulation results, cast severe doubt on the validity of the surface structure claimed in the paper referenced in the title.
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Affiliation(s)
- Moshe Deutsch
- Physics Department and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel.
| | - Olaf M Magnussen
- Institute for Experimental and Applied Physics and Ruprecht-Haensel Laboratory, Kiel University, 24118 Kiel, Germany
| | - Julia Haddad
- Physics Department and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel.
| | - Diego Pontoni
- Partnership for Soft Condensed Matter (PSCM), ESRF - The European Synchrotron, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Bridget M Murphy
- Institute for Experimental and Applied Physics and Ruprecht-Haensel Laboratory, Kiel University, 24118 Kiel, Germany
| | - Benjamin M Ocko
- NSLS-II, Brookhaven National Laboratory, Upton, New York 11973, USA
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12
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Lambie S, Steenbergen KG, Gaston N. Modulating the thermal and structural stability of gallenene via variation of atomistic thickness. NANOSCALE ADVANCES 2021; 3:499-507. [PMID: 36131742 PMCID: PMC9418766 DOI: 10.1039/d0na00737d] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/05/2020] [Indexed: 06/15/2023]
Abstract
Using ab initio molecular dynamics, we show that a recently discovered form of 2D Ga-gallenene-exhibits highly variable thickness dependent properties. Here, 2D Ga of four, five and six atomic layers thick are found to be thermally stable to 457 K, 350 K and 433 K, respectively; all well above that of bulk Ga. Analysis of the liquid structure of 2D Ga shows a thickness dependent ordering both parallel and perpendicular to the Ga/vacuum interface. Furthermore, ground state optimisations of 2D Ga to 12 atomic layers thick shows a return to a bulk-like bonding structure at 10 atoms thick, therefore we anticipate that up to this thickness 2D Ga structures will each exhibit novel properties as discrete 2D materials. Gallenene has exciting potential applications in plasmonics, sensors and electrical contacts however, for the potential of 2D Ga to be fully realised an in depth understanding of its thickness dependent properties is required.
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Affiliation(s)
- Stephanie Lambie
- Department of Physics, MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Auckland Private Bag 92019 Auckland New Zealand
| | - Krista G Steenbergen
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington P.O. Box 600 Wellington 6140 New Zealand
| | - Nicola Gaston
- Department of Physics, MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Auckland Private Bag 92019 Auckland New Zealand
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13
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Prihoda A, Will J, Duchstein P, Becit B, Lossin F, Schindler T, Berlinghof M, Steinrück HG, Bertram F, Zahn D, Unruh T. Interface between Water-Solvent Mixtures and a Hydrophobic Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12077-12086. [PMID: 32960065 DOI: 10.1021/acs.langmuir.0c02745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The mechanism behind the stability of organic nanoparticles prepared by liquid antisolvent (LAS) precipitation without a specific stabilizing agent is poorly understood. In this work, we propose that the organic solvent used in the LAS process rapidly forms a molecular stabilizing layer at the interface of the nanoparticles with the aqueous dispersion medium. To confirm this hypothesis, n-octadecyltrichlorosilane (OTS)-functionalized silicon wafers in contact with water-solvent mixtures were used as a flat model system mimicking the solid-liquid interface of the organic nanoparticles. We studied the equilibrium structure of the interface by X-ray reflectometry (XRR) for water-solvent mixtures (methanol, ethanol, 1-propanol, 2-propanol, acetone, and tetrahydrofuran). The formation of an organic solvent-rich layer at the solid-liquid interface was observed. The layer thickness increases with the organic solvent concentration and correlates with the polar and hydrogen bond fraction of Hansen solubility parameters. We developed a self-consistent adsorption model via complementing adsorption isotherms obtained from XRR data with molecular dynamics simulations.
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Affiliation(s)
- Annemarie Prihoda
- Institute for Crystallography and Structural Physics (ICSP), Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 3, 91058 Erlangen, Germany
- Center for Nanoanalysis and Electron Microscopy (CENEM) and Interdisciplinary Center for Nanostructured Films (IZNF), Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
| | - Johannes Will
- Center for Nanoanalysis and Electron Microscopy (CENEM) and Interdisciplinary Center for Nanostructured Films (IZNF), Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
- Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung), Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
| | - Patrick Duchstein
- Computer Chemistry Centre (CCC), Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstr. 25, 91052 Erlangen, Germany
| | - Bahanur Becit
- Computer Chemistry Centre (CCC), Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstr. 25, 91052 Erlangen, Germany
| | - Felix Lossin
- Institute for Crystallography and Structural Physics (ICSP), Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 3, 91058 Erlangen, Germany
| | - Torben Schindler
- Institute for Crystallography and Structural Physics (ICSP), Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 3, 91058 Erlangen, Germany
| | - Marvin Berlinghof
- Institute for Crystallography and Structural Physics (ICSP), Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 3, 91058 Erlangen, Germany
| | - Hans-Georg Steinrück
- Department Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | | | - Dirk Zahn
- Computer Chemistry Centre (CCC), Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstr. 25, 91052 Erlangen, Germany
| | - Tobias Unruh
- Institute for Crystallography and Structural Physics (ICSP), Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 3, 91058 Erlangen, Germany
- Center for Nanoanalysis and Electron Microscopy (CENEM) and Interdisciplinary Center for Nanostructured Films (IZNF), Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
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14
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Vis M, Brouwer KJH, González García Á, Petukhov AV, Konovalov O, Tuinier R. Quantification of the Structure of Colloidal Gas-Liquid Interfaces. J Phys Chem Lett 2020; 11:8372-8377. [PMID: 32957778 PMCID: PMC7528408 DOI: 10.1021/acs.jpclett.0c02464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 09/15/2020] [Indexed: 05/17/2023]
Abstract
We have quantified the structure of the colloidal gas-liquid interface using synchrotron X-ray reflectivity measurements on a model colloid-polymer mixture. The interfacial width shows mean-field scaling with the colloid density difference, and the density profiles appear to be monotonic. Furthermore, our measurements allow us to distinguish between different theoretical polymer descriptions commonly used to model colloid-polymer mixtures. Our results highlight the importance of capturing the correct polymer physics in obtaining a quantitative theoretical description of the colloidal gas-liquid interface.
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Affiliation(s)
- Mark Vis
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Kelly J H Brouwer
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, 3508 TA Utrecht, The Netherlands
| | - Álvaro González García
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, 3508 TA Utrecht, The Netherlands
| | - Andrei V Petukhov
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, 3508 TA Utrecht, The Netherlands
| | - Oleg Konovalov
- European Synchroton Radiation Facility, 38000 Grenoble, France
| | - Remco Tuinier
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
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15
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Festersen S, Runge B, Koops C, Bertram F, Ocko B, Deutsch M, Murphy BM, Magnussen OM. Nucleation and Growth of PbBrF Crystals at the Liquid Mercury-Electrolyte Interface Studied by Operando X-ray Scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:10905-10915. [PMID: 32905700 DOI: 10.1021/acs.langmuir.0c01199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Detailed in operando studies of electrochemically induced PbBrF deposition at the liquid mercury/liquid electrolyte interface are presented. The nucleation and growth were monitored using time-resolved X-ray diffraction and reflectivity combined with electrochemical measurements, revealing a complex potential-dependent behavior. PbBrF deposition commences at potentials above -0.7 V with the rapid formation of an ultrathin adlayer of one unit cell thickness, on top of which (001)-oriented three-dimensional crystallites are formed. Two potential regimes are identified. At low overpotentials, slow growth of a low surface density film of large crystals is observed. At high overpotentials, crossover to a potential-independent morphology occurs, consisting of a compact PbBrF deposit with a saturation thickness of 25 nm, which forms within a few minutes. This potential behavior can be rationalized by the increasing supersaturation near the interface, caused by the potential-dependent Pb2+ deamalgamation, which changes from a slow reaction-controlled process to a fast transport-controlled process in this range of overpotentials. In addition, growth on the liquid substrate is found to involve complex micromechanical effects, such as crystal reorientation and film breakup during dissolution.
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Affiliation(s)
- Sven Festersen
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
| | - Benjamin Runge
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
| | - Christian Koops
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
| | - Florian Bertram
- Deutsches Elektronensynchrotron DESY, 22607 Hamburg, Germany
| | - Ben Ocko
- NSLS-II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Moshe Deutsch
- Physics Department & Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Bridget M Murphy
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
- Ruprecht-Haensel Laboratory, Kiel University, 24118 Kiel, Germany
| | - Olaf M Magnussen
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
- Ruprecht-Haensel Laboratory, Kiel University, 24118 Kiel, Germany
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16
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Katakura S, Amano KI, Sakka T, Bu W, Lin B, Schlossman ML, Nishi N. Evolution and Reversible Polarity of Multilayering at the Ionic Liquid/Water Interface. J Phys Chem B 2020; 124:6412-6419. [PMID: 32600035 DOI: 10.1021/acs.jpcb.0c03711] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Highly correlated positioning of ions underlies Coulomb interactions between ions and electrified interfaces within dense ionic fluids such as biological cells and ionic liquids. Recent work has shown that highly correlated ionic systems behave differently than dilute electrolyte solutions, and interest is focused upon characterizing the electrical and structural properties of the dense electrical double layers (EDLs) formed at internal interfaces. It has been a challenge for experiments to characterize the progressive development of the EDL on the nanoscale as the interfacial electric potential is varied over a range of positive and negative values. Here we address this challenge by measuring X-ray reflectivity from the interface between an ionic liquid (IL) and a dilute aqueous electrolyte solution over a range of interfacial potentials from -450 to 350 mV. The growth of alternately charged cation-rich and anion-rich layers was observed along with a polarity reversal of the layers as the potential changed sign. These data show that the structural development of an ionic multilayer-like EDL with increasing potential is similar to that suggested by phenomenological theories and MD simulations, although our data also reveal that the excess charge beyond the first ionic layer decays more rapidly than predicted.
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Affiliation(s)
- Seiji Katakura
- Department of Energy and Hydrocarbon Chemistry, Kyoto University, Kyoto 615-8510, Japan
| | - Ken-Ichi Amano
- Department of Energy and Hydrocarbon Chemistry, Kyoto University, Kyoto 615-8510, Japan.,Faculty of Agriculture, Meijo University, Nagoya, Aichi 468-8502, Japan
| | - Tetsuo Sakka
- Department of Energy and Hydrocarbon Chemistry, Kyoto University, Kyoto 615-8510, Japan
| | - Wei Bu
- ChemMatCARS, Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, United States
| | - Binhua Lin
- ChemMatCARS, Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, United States
| | - Mark L Schlossman
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Naoya Nishi
- Department of Energy and Hydrocarbon Chemistry, Kyoto University, Kyoto 615-8510, Japan
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17
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de Jong AEF, Vonk V, Boćkowski M, Grzegory I, Honkimäki V, Vlieg E. Complex Geometric Structure of a Simple Solid-Liquid Interface: GaN(0001)-Ga. PHYSICAL REVIEW LETTERS 2020; 124:086101. [PMID: 32167331 DOI: 10.1103/physrevlett.124.086101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
The equilibrium atomic interface structure between Ga and GaN(0001) is shown to contain substrate surface vacancies followed by substrate-induced layering and preferential lateral ordering in the liquid. The uncovered presence of point defects, in the form of vacancies at both sides of the solid-liquid interface, is an important structural feature which governs the local physical properties. Our x-ray diffraction study reveals that the layering is very stable and persists up to a temperature of 1123 K and a nitrogen pressure of 32 bar. The Ga layer spacing agrees remarkably well with the Friedel oscillation period for this system.
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Affiliation(s)
- A E F de Jong
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525AJ Nijmegen, Netherlands
- European Synchrotron Radiation Facility, CS 40220, F-38043, Grenoble Cedex 9, France
| | - V Vonk
- DESY NanoLaboratory, Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, D-22607 Hamburg, Germany
| | - M Boćkowski
- Institute of High Pressure Physics PAS, Sokolowska 29/37, 01-142 Warsaw, Poland
| | - I Grzegory
- Institute of High Pressure Physics PAS, Sokolowska 29/37, 01-142 Warsaw, Poland
| | - V Honkimäki
- European Synchrotron Radiation Facility, CS 40220, F-38043, Grenoble Cedex 9, France
| | - E Vlieg
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525AJ Nijmegen, Netherlands
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18
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Sakaushi K, Kumeda T, Hammes-Schiffer S, Melander MM, Sugino O. Advances and challenges for experiment and theory for multi-electron multi-proton transfer at electrified solid–liquid interfaces. Phys Chem Chem Phys 2020; 22:19401-19442. [DOI: 10.1039/d0cp02741c] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Understanding microscopic mechanism of multi-electron multi-proton transfer reactions at complexed systems is important for advancing electrochemistry-oriented science in the 21st century.
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Affiliation(s)
- Ken Sakaushi
- Center for Green Research on Energy and Environmental Materials
- National Institute for Materials Science
- Ibaraki 305-0044
- Japan
| | - Tomoaki Kumeda
- Center for Green Research on Energy and Environmental Materials
- National Institute for Materials Science
- Ibaraki 305-0044
- Japan
| | | | - Marko M. Melander
- Nanoscience Center
- Department of Chemistry
- University of Jyväskylä
- Jyväskylä
- Finland
| | - Osamu Sugino
- The Institute of Solid State Physics
- the University of Tokyo
- Chiba 277-8581
- Japan
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19
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Delcea M, Helm CA. X-ray and Neutron Reflectometry of Thin Films at Liquid Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:8519-8530. [PMID: 30901219 DOI: 10.1021/acs.langmuir.8b04315] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In the 1980s, Helmuth Möhwald studied lipid monolayers at the air/water interface to understand the thermodynamically characterized phases at the molecular level. In collaboration with Jens Als-Nielsen, X-ray reflectometry was used and further developed to determine the electron density profile perpendicular to the water surface. Using a slab model, parameters such as thickness and density of the individual molecular regions, as well as the roughness of the individual interfaces, were determined. Later, X-ray and neutron reflectometry helped to understand the coverage and conformation of anchored and adsorbed polymers. Nowadays, they resolve molecular properties in emerging topics such as liquid metals and ionic liquids. Much is still to be learned about buried interfaces (e.g., liquid/liquid interfaces). In this Article, a historical and theoretical background of X-ray reflectivity is given, recent developments of X-ray and neutron reflectometry for polymers at interfaces and thin layers are highlighted, and emerging research topics involving these techniques are emphasized.
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Affiliation(s)
- Mihaela Delcea
- Institute of Biochemistry , University of Greifswald , Felix-Hausdorff-Straße 4 , 17489 Greifswald , Germany
- ZIK HIKE- Zentrum für Innovationskompetenz , Humorale Immunreaktionen bei kardiovaskulären Erkrankungen , Fleischmannstraße 42 , 17489 Greifswald , Germany
| | - Christiane A Helm
- Institute of Physics , University of Greifswald , Felix-Hausdorff-Straße 4 , 17489 Greifswald , Germany
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20
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Thomä SLJ, Krauss SW, Eckardt M, Chater P, Zobel M. Atomic insight into hydration shells around facetted nanoparticles. Nat Commun 2019; 10:995. [PMID: 30824693 PMCID: PMC6397290 DOI: 10.1038/s41467-019-09007-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/08/2019] [Indexed: 01/10/2023] Open
Abstract
Nanoparticles in solution interact with their surroundings via hydration shells. Although the structure of these shells is used to explain nanoscopic properties, experimental structural insight is still missing. Here we show how to access the hydration shell structures around colloidal nanoparticles in scattering experiments. For this, we synthesize variably functionalized magnetic iron oxide nanoparticle dispersions. Irrespective of the capping agent, we identify three distinct interatomic distances within 2.5 Å from the particle surface which belong to dissociatively and molecularly adsorbed water molecules, based on theoretical predictions. A weaker restructured hydration shell extends up to 15 Å. Our results show that the crystal structure dictates the hydration shell structure. Surprisingly, facets of 7 and 15 nm particles behave like planar surfaces. These findings bridge the large gap between spectroscopic studies on hydrogen bond networks and theoretical advances in solvation science.
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Affiliation(s)
- Sabrina L J Thomä
- Department of Chemistry, University of Bayreuth, Universitätsstr.30, 95440, Bayreuth, Germany
| | - Sebastian W Krauss
- Department of Chemistry, University of Bayreuth, Universitätsstr.30, 95440, Bayreuth, Germany
| | - Mirco Eckardt
- Department of Chemistry, University of Bayreuth, Universitätsstr.30, 95440, Bayreuth, Germany
| | - Phil Chater
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Mirijam Zobel
- Department of Chemistry, University of Bayreuth, Universitätsstr.30, 95440, Bayreuth, Germany.
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21
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Panciera F, Tersoff J, Gamalski AD, Reuter MC, Zakharov D, Stach EA, Hofmann S, Ross FM. Surface Crystallization of Liquid Au-Si and Its Impact on Catalysis. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806544. [PMID: 30516864 DOI: 10.1002/adma.201806544] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/12/2018] [Indexed: 06/09/2023]
Abstract
In situ transmission electron microscopy reveals that an atomically thin crystalline phase at the surface of liquid Au-Si is stable over an unexpectedly wide range of conditions. By measuring the surface structure as a function of liquid temperature and composition, a simple thermodynamic model is developed to explain the stability of the ordered phase. The presence of surface ordering plays a key role in the pathway by which the Au-Si eutectic solidifies and also dramatically affects the catalytic properties of the liquid, explaining the anomalously slow growth kinetics of Si nanowires at low temperature. A strategy to control the presence of the surface phase is discussed, using it as a tool in designing strategies for nanostructure growth.
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Affiliation(s)
- Federico Panciera
- Department of Engineering, University of Cambridge, 9 J. J. Thomson Avenue, Cambridge, CB3 0FA, UK
- IBM T. J. Watson Research Center, Yorktown Heights, NY, 10598, USA
| | - Jerry Tersoff
- IBM T. J. Watson Research Center, Yorktown Heights, NY, 10598, USA
| | - Andrew D Gamalski
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Mark C Reuter
- IBM T. J. Watson Research Center, Yorktown Heights, NY, 10598, USA
| | - Dmitri Zakharov
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Eric A Stach
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Stephan Hofmann
- Department of Engineering, University of Cambridge, 9 J. J. Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Frances M Ross
- IBM T. J. Watson Research Center, Yorktown Heights, NY, 10598, USA
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22
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Hernández-Muñoz J, Chacón E, Tarazona P. Density correlation in liquid surfaces: Bedeaux-Weeks high order terms and non capillary wave background. J Chem Phys 2018; 149:124704. [PMID: 30278660 DOI: 10.1063/1.5049874] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We present Molecular Dynamics (MD) simulations of liquid-vapor surfaces, and their Intrinsic Sampling Method analysis, to get a quantitative test for the theoretical prediction of the capillary wave (CW) effects on density correlation done by Bedeaux and Weeks (BW) in 1985. The results are contrasted with Wertheim's proposal which is the first term in BW series and are complemented with a (formally defined and computational accessible) proposal for the background of non-CW fluctuations. Our conclusion is that BW theory is both accurate and needed since it may differ significantly from Wertheim's proposal. We discuss the implications for the analysis of experimental X-ray surface diffraction data and MD simulations.
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Affiliation(s)
- Jose Hernández-Muñoz
- Departamento de Física Teórica de la Materia Condensada, IFIMAC Condensed Matter Physics Center, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Enrique Chacón
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Madrid 28049, Spain
| | - Pedro Tarazona
- Departamento de Física Teórica de la Materia Condensada, IFIMAC Condensed Matter Physics Center, and Instituto Nicolás Cabrera de Ciencia de Materiales, Universidad Autónoma de Madrid, Madrid 28049, Spain
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23
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Horowitz Y, Steinrück HG, Han HL, Cao C, Abate II, Tsao Y, Toney MF, Somorjai GA. Fluoroethylene Carbonate Induces Ordered Electrolyte Interface on Silicon and Sapphire Surfaces as Revealed by Sum Frequency Generation Vibrational Spectroscopy and X-ray Reflectivity. NANO LETTERS 2018; 18:2105-2111. [PMID: 29451803 DOI: 10.1021/acs.nanolett.8b00298] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The cyclability of silicon anodes in lithium ion batteries (LIBs) is affected by the reduction of the electrolyte on the anode surface to produce a coating layer termed the solid electrolyte interphase (SEI). One of the key steps for a major improvement of LIBs is unraveling the SEI's structure-related diffusion properties as charge and discharge rates of LIBs are diffusion-limited. To this end, we have combined two surface sensitive techniques, sum frequency generation (SFG) vibrational spectroscopy, and X-ray reflectivity (XRR), to explore the first monolayer and to probe the first several layers of electrolyte, respectively, for solutions consisting of 1 M lithium perchlorate (LiClO4) salt dissolved in ethylene carbonate (EC) or fluoroethylene carbonate (FEC) and their mixtures (EC/FEC 7:3 and 1:1 wt %) on silicon and sapphire surfaces. Our results suggest that the addition of FEC to EC solution causes the first monolayer to rearrange itself more perpendicular to the anode surface, while subsequent layers are less affected and tend to maintain their, on average, surface-parallel arrangements. This fundamental understanding of the near-surface orientation of the electrolyte molecules can aid operational strategies for designing high-performance LIBs.
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Affiliation(s)
- Yonatan Horowitz
- Department of Chemistry, Kavli Energy NanoScience Institute , University of California, Berkeley , Berkeley , California 94720 , United States
- Materials Sciences Division , Lawrence Berkeley National Laboratory , 1 Cyclotron Road , Berkeley , California 94720 , United States
| | - Hans-Georg Steinrück
- SSRL Materials Science Division , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Hui-Ling Han
- Department of Chemistry, Kavli Energy NanoScience Institute , University of California, Berkeley , Berkeley , California 94720 , United States
- Materials Sciences Division , Lawrence Berkeley National Laboratory , 1 Cyclotron Road , Berkeley , California 94720 , United States
| | - Chuntian Cao
- SSRL Materials Science Division , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
- Department of Materials Science and Engineering , Stanford University , Stanford , California 94305 , United States
| | - Iwnetim Iwnetu Abate
- SSRL Materials Science Division , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
- Department of Materials Science and Engineering , Stanford University , Stanford , California 94305 , United States
| | - Yuchi Tsao
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Michael F Toney
- SSRL Materials Science Division , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Gabor A Somorjai
- Department of Chemistry, Kavli Energy NanoScience Institute , University of California, Berkeley , Berkeley , California 94720 , United States
- Materials Sciences Division , Lawrence Berkeley National Laboratory , 1 Cyclotron Road , Berkeley , California 94720 , United States
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24
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Festersen S, Hrkac SB, Koops CT, Runge B, Dane T, Murphy BM, Magnussen OM. X-ray reflectivity from curved liquid interfaces. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:432-438. [PMID: 29488923 DOI: 10.1107/s1600577517018057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/18/2017] [Indexed: 06/08/2023]
Abstract
X-ray reflectivity studies of the structure of liquid-vapour and liquid-liquid interfaces at modern sources, such as free-electron lasers, are currently impeded by the lack of dedicated liquid surface diffractometers. It is shown that this obstacle can be overcome by an alternative experimental approach that uses the natural curvature of a liquid drop for variation of the angle of incidence. Two modes of operation are shown: (i) sequential reflectivity measurements by a nanometre beam and (ii) parallel acquisition of large ranges of a reflectivity curve by micrometre beams. The feasibility of the two methods is demonstrated by studies of the Hg/vapour, H2O/vapour and Hg/0.1 M NaF interface. The obtained reflectivity curves match the data obtained by conventional techniques up to 5αc in micro-beam mode and up to 35αc in nano-beam mode, allowing observation of the Hg layering peak.
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Affiliation(s)
- Sven Festersen
- Institute for Experimental and Applied Physics, Kiel University, Kiel, Germany
| | - Stjepan B Hrkac
- Institute for Experimental and Applied Physics, Kiel University, Kiel, Germany
| | - Christian T Koops
- Institute for Experimental and Applied Physics, Kiel University, Kiel, Germany
| | - Benjamin Runge
- Institute for Experimental and Applied Physics, Kiel University, Kiel, Germany
| | - Thomas Dane
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Bridget M Murphy
- Institute for Experimental and Applied Physics, Kiel University, Kiel, Germany
| | - Olaf M Magnussen
- Institute for Experimental and Applied Physics, Kiel University, Kiel, Germany
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25
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Haddad J, Pontoni D, Murphy BM, Festersen S, Runge B, Magnussen OM, Steinrück HG, Reichert H, Ocko BM, Deutsch M. Surface structure evolution in a homologous series of ionic liquids. Proc Natl Acad Sci U S A 2018; 115:E1100-E1107. [PMID: 29358372 PMCID: PMC5819424 DOI: 10.1073/pnas.1716418115] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interfaces of room temperature ionic liquids (RTILs) are important for both applications and basic science and are therefore intensely studied. However, the evolution of their interface structure with the cation's alkyl chain length [Formula: see text] from Coulomb to van der Waals interaction domination has not yet been studied for even a single broad homologous RTIL series. We present here such a study of the liquid-air interface for [Formula: see text], using angstrom-resolution X-ray methods. For [Formula: see text], a typical "simple liquid" monotonic surface-normal electron density profile [Formula: see text] is obtained, like those of water and organic solvents. For [Formula: see text], increasingly more pronounced nanoscale self-segregation of the molecules' charged moieties and apolar chains yields surface layering with alternating regions of headgroups and chains. The layering decays into the bulk over a few, to a few tens, of nanometers. The layering periods and decay lengths, their linear [Formula: see text] dependence, and slopes are discussed within two models, one with partial-chain interdigitation and the other with liquid-like chains. No surface-parallel long-range order is found within the surface layer. For [Formula: see text], a different surface phase is observed above melting. Our results also impact general liquid-phase issues like supramolecular self-aggregation and bulk-surface structure relations.
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Affiliation(s)
- Julia Haddad
- Physics Department, Bar-Ilan University, Ramat Gan 5290002, Israel
- Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Diego Pontoni
- European Synchrotron Radiation Facility, The European Synchrotron and Partnership for Soft Condensed Matter (PSCM), 38000 Grenoble, France
| | - Bridget M Murphy
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
- Ruprecht Haensel Laboratory, Kiel University, 24098 Kiel, Germany
| | - Sven Festersen
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
| | - Benjamin Runge
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
| | - Olaf M Magnussen
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
- Ruprecht Haensel Laboratory, Kiel University, 24098 Kiel, Germany
| | - Hans-Georg Steinrück
- Stanford Synchrotron Radiation Laboratory (SSRL) Materials Science Division, Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory, Menlo Park, CA 94025
| | - Harald Reichert
- European Synchrotron Radiation Facility, The European Synchrotron, 38000 Grenoble, France
| | - Benjamin M Ocko
- National Synchrotron Light Source II (NSLS-II), Brookhaven National Laboratory, Upton, NY 11973
| | - Moshe Deutsch
- Physics Department, Bar-Ilan University, Ramat Gan 5290002, Israel;
- Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
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26
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Sega M. The role of a small-scale cutoff in determining molecular layers at fluid interfaces. Phys Chem Chem Phys 2018; 18:23354-7. [PMID: 27499039 DOI: 10.1039/c6cp04788b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The existence of molecular layers at liquid/vapour interfaces has been a long debated issue. More than ten years ago it was shown, using computer simulations, that correlations at the liquid/vapour interface resemble those of bulk liquids, even though they can be detected in experiments only in a few cases, where they are so strong that they cannot be concealed by the geometrical smearing of capillary fluctuations. The results of the intrinsic analysis techniques used in computer experiments, however, are still often questioned because of their dependence on a free parameter that usually represents a small-scale cutoff used to determine the interface. In this work I show that there is only one value of the cutoff that can ensure a quantitative explanation of the intrinsic density correlation peaks in terms of successive layer contributions. The value of the cutoff coincides, with a high accuracy, with the molecular diameter.
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Affiliation(s)
- Marcello Sega
- University of Vienna, Computational Physics Group, Sensengasse 8/9, 1090 Vienna, Austria.
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27
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Reichert P, Kjær KS, Brandt van Driel T, Mars J, Ochsmann JW, Pontoni D, Deutsch M, Nielsen MM, Mezger M. Molecular scale structure and dynamics at an ionic liquid/electrode interface. Faraday Discuss 2018; 206:141-157. [DOI: 10.1039/c7fd00171a] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structural arrangement and dynamics of ions near the IL/electrode interface during charging and discharging was studied by a combination of time resolved X-ray reflectivity and impedance spectroscopy.
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Affiliation(s)
- Peter Reichert
- Max Planck Institute for Polymer Research
- 55128 Mainz
- Germany
- Institute of Physics and MAINZ Graduate School
- Johannes Gutenberg University Mainz
| | - Kasper Skov Kjær
- Centre for Molecular Movies
- Department of Physics
- Technical University of Denmark
- DK-2800 Lyngby
- Denmark
| | - Tim Brandt van Driel
- Centre for Molecular Movies
- Department of Physics
- Technical University of Denmark
- DK-2800 Lyngby
- Denmark
| | - Julian Mars
- Max Planck Institute for Polymer Research
- 55128 Mainz
- Germany
- Institute of Physics and MAINZ Graduate School
- Johannes Gutenberg University Mainz
| | | | - Diego Pontoni
- ESRF – The European Synchrotron and Partnership for Soft Condensed Matter (PSCM)
- 38043 Grenoble
- France
| | - Moshe Deutsch
- Department of Physics
- Institute of Nanotechnology and Advanced Materials
- Bar-Ilan University
- Ramat-Gan 52900
- Israel
| | - Martin Meedom Nielsen
- Centre for Molecular Movies
- Department of Physics
- Technical University of Denmark
- DK-2800 Lyngby
- Denmark
| | - Markus Mezger
- Max Planck Institute for Polymer Research
- 55128 Mainz
- Germany
- Institute of Physics and MAINZ Graduate School
- Johannes Gutenberg University Mainz
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28
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Pontoni D, Haddad J, Di Michiel M, Deutsch M. Self-segregated nanostructure in room temperature ionic liquids. SOFT MATTER 2017; 13:6947-6955. [PMID: 28849840 DOI: 10.1039/c7sm01464c] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The nanosegregated bulk structure, and its evolution with the cation's alkyl length n, are studied by X-ray scattering for an unprecedentedly broad homologous series of a model room-temperature ionic liquid, [CnMIM][NTf2] (n = 4-22). A tri-periodic local structure is found, with the lateral periodicities, dII and dIII independent of n, and a longitudinal one, dI, linearly increasing with n. The results are consistent with a local structure comprising alternating layers of polar headgroups and apolar, interdigitated, partly overlapping, cations' alkyl tails, of an average macroscopic mass density close to that of liquid alkanes. A slope decrease in the linear dI(n) suggests a change from a lower to a higher rate of increase with n of chain overlap for n ≥ 12. The order decay lengths of the layering, and of the lateral chain packing, increase with n, as expected from the increasing van der Waals interaction's domination of the structure. The headgroups' lateral packing decay length decreases with n, due to increasing frustration between the longer lateral periodicity preferred by the headgroups, and the shorter lateral periodicity preferred by the chains. A comparison of the bulk and surface structures highlights the surface's ordering effect, which, however, does not induce here a surface phase different from the bulk, as it does in liquid crystals and liquid alkanes.
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Affiliation(s)
- Diego Pontoni
- ESRF - The European Synchrotron and Partnership for Soft Condensed Matter (PSCM), 71 Avenue des Martyrs, 38000 Grenoble, France
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29
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Škvor J, Škvára J, Jirsák J, Nezbeda I. A general method for determining molecular interfaces and layers. J Mol Graph Model 2017; 76:17-35. [PMID: 28668730 DOI: 10.1016/j.jmgm.2017.05.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 05/22/2017] [Accepted: 05/23/2017] [Indexed: 11/30/2022]
Abstract
A general and direct computational scheme to locate the surface separating arbitrarily shaped domains made up of molecules (or any other particles) has been developed and is described and illustrated for several, both artificial and physical examples. The proposed scheme consists of two modules: (i) triangulation and (ii) assignment of simplices to domains. Three different triangulation methods are employed, viz., the Delaunay triangulation, regular triangulation, and quasi-triangulation. In the triangulated system, the assignment step is carried out in two different ways, one based on the characteristic metric of a particular triangulation procedure and the other on the concept of a touching sphere. Some of the combinations of the triangulation and assignment steps lead to methods already used by others to find interfacial or surface molecules, namely the alpha-shape-based method of Usabiaga nad Duque [Phys. Rev. E 79 (2009) 046709] and GITIM of Sega et al. [J. Chem. Phys. 138 (2013) 044110]. The resulting surface is defined not only as a discrete set of particles, but it is build up of facets of the triangulation forming a broken line in two dimensions or a polyhedral surface in three dimensions. Individual molecular layers are identified in a very straightforward manner, starting with the interfacial layer itself and proceeding into the interior of the phase. The proposed scheme is illustrated first by identifying border molecules of pre-sampled domains of several shapes in a plane and then applied to five physically meaningful examples: thin films, near critical water, liquid water slab in an electric field, liquid water at a solid wall, and water at condition of electric-field-induced jetting. Performance of the considered methods is critically assessed. Treatment of domains forming percolating clusters through periodic boundary conditions is also described along with the determination of their periodicity and dimensionality.
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Affiliation(s)
- Jiří Škvor
- Faculty of Science, Jan Evangelista Purkyně University in Ústí nad Labem, 400 96 Ústí nad Labem, Czechia.
| | - Jiří Škvára
- Faculty of Science, Jan Evangelista Purkyně University in Ústí nad Labem, 400 96 Ústí nad Labem, Czechia
| | - Jan Jirsák
- Faculty of Science, Jan Evangelista Purkyně University in Ústí nad Labem, 400 96 Ústí nad Labem, Czechia; Institute of Chemical Process Fundamentals, Czech Academy of Sciences, 165 02 Prague 6 - Suchdol, Czechia
| | - Ivo Nezbeda
- Faculty of Science, Jan Evangelista Purkyně University in Ústí nad Labem, 400 96 Ústí nad Labem, Czechia; Institute of Chemical Process Fundamentals, Czech Academy of Sciences, 165 02 Prague 6 - Suchdol, Czechia
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30
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Affiliation(s)
- Kun Dong
- State Key Laboratory of Multiphase
Complex Systems, Beijing Key Laboratory of Ionic Liquids Clean Process,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaomin Liu
- State Key Laboratory of Multiphase
Complex Systems, Beijing Key Laboratory of Ionic Liquids Clean Process,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Haifeng Dong
- State Key Laboratory of Multiphase
Complex Systems, Beijing Key Laboratory of Ionic Liquids Clean Process,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiangping Zhang
- State Key Laboratory of Multiphase
Complex Systems, Beijing Key Laboratory of Ionic Liquids Clean Process,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Suojiang Zhang
- State Key Laboratory of Multiphase
Complex Systems, Beijing Key Laboratory of Ionic Liquids Clean Process,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
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31
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del Rio BG, González LE. Orbital-free ab initio molecular dynamics study of the static structure and dynamic properties of the free liquid surface of Sn. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201715103003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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del Rio BG, Souto J, Alemany MMG, González LE. Ab initio study of intrinsic profiles of liquid metals and their reflectivity. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201715105002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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33
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Sun J, Wang HS. On the early and developed stages of surface condensation: competition mechanism between interfacial and condensate bulk thermal resistances. Sci Rep 2016; 6:35003. [PMID: 27721397 PMCID: PMC5056363 DOI: 10.1038/srep35003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 09/22/2016] [Indexed: 11/21/2022] Open
Abstract
We use molecular dynamics simulation to investigate the early and developed stages of surface condensation. We find that the liquid-vapor and solid-liquid interfacial thermal resistances depend on the properties of solid and fluid, which are time-independent, while the condensate bulk thermal resistance depends on the condensate thickness, which is time-dependent. There exists intrinsic competition between the interfacial and condensate bulk thermal resistances in timeline and the resultant total thermal resistance determines the condensation intensity for a given vapor-solid temperature difference. We reveal the competition mechanism that the interfacial thermal resistance dominates at the onset of condensation and holds afterwards while the condensate bulk thermal resistance gradually takes over with condensate thickness growing. The weaker the solid-liquid bonding, the later the takeover occurs. This competition mechanism suggests that only when the condensate bulk thermal resistance is reduced after it takes over the domination can the condensation be effectively intensified. We propose a unified theoretical model for the thermal resistance analysis by making dropwise condensation equivalent to filmwise condensation. We further find that near a critical point (contact angle being ca. 153°) the bulk thermal resistance has the least opportunity to take over the domination while away from it the probability increases.
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Affiliation(s)
- Jie Sun
- Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hua Sheng Wang
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
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34
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Zobel M. Observing structural reorientations at solvent–nanoparticle interfaces by X-ray diffraction – putting water in the spotlight. ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES 2016; 72:621-631. [DOI: 10.1107/s2053273316013516] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 08/22/2016] [Indexed: 01/29/2023]
Abstract
Nanoparticles are attractive in a wide range of research genres due to their size-dependent properties, which can be in contrast to those of micrometre-sized colloids or bulk materials. This may be attributed, in part, to their large surface-to-volume ratio and quantum confinement effects. There is a growing awareness that stress and strain at the particle surface contribute to their behaviour and this has been included in the structural models of nanoparticles for some time. One significant oversight in this field, however, has been the fact that the particle surface affects its surroundings in an equally important manner. It should be emphasized here that the surface areas involved are huge and, therefore, a significant proportion of solvent molecules are affected. Experimental evidence of this is emerging, where suitable techniques to probe the structural correlations of liquids at nanoparticle surfaces have only recently been developed. The recent validation of solvation shells around nanoparticles has been a significant milestone in advancing this concept. Restructured ordering of solvent molecules at the surfaces of nanoparticles has an influence on the entire panoply of solvent–particle interactions during, for example, particle formation and growth, adhesion forces in industrial filtration, and activities of nanoparticle–enzyme complexes. This article gives an overview of the advances made in solvent–nanoparticle interface research in recent years: from description of the structure of bulk solids and liquidsviamacroscopic planar surfaces, to the detection of nanoscopic restructuring effects. Water–nanoparticle interfaces are given specific attention to illustrate and highlight their similarity to biological systems.
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35
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Murphy BM, Festersen S, Magnussen OM. The Atomic scale structure of liquid metal-electrolyte interfaces. NANOSCALE 2016; 8:13859-13866. [PMID: 27301317 DOI: 10.1039/c6nr01571a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electrochemical interfaces between immiscible liquids have lately received renewed interest, both for gaining fundamental insight as well as for applications in nanomaterial synthesis. In this feature article we demonstrate that the atomic scale structure of these previously inaccessible interfaces nowadays can be explored by in situ synchrotron based X-ray scattering techniques. Exemplary studies of a prototypical electrochemical system - a liquid mercury electrode in pure NaCl solution - reveal that the liquid metal is terminated by a well-defined atomic layer. This layering decays on length scales of 0.5 nm into the Hg bulk and displays a potential and temperature dependent behaviour that can be explained by electrocapillary effects and contributions of the electronic charge distribution on the electrode. In similar studies of nanomaterial growth, performed for the electrochemical deposition of PbFBr, a complex nucleation and growth behaviour is found, involving a crystalline precursor layer prior to the 3D crystal growth. Operando X-ray scattering measurements provide detailed data on the processes of nanoscale film formation.
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Affiliation(s)
- B M Murphy
- Institute of Experimental and Applied Physics, Kiel University, Leibnizstr. 19, D-24098 Kiel, Germany.
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36
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The Hydration Structure at Yttria-Stabilized Cubic Zirconia (110)-Water Interface with Sub-Ångström Resolution. Sci Rep 2016; 6:27916. [PMID: 27302473 PMCID: PMC4908582 DOI: 10.1038/srep27916] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 05/26/2016] [Indexed: 11/19/2022] Open
Abstract
The interfacial hydration structure of yttria-stabilized cubic zirconia (110) surface in contact with water was determined with ~0.5 Å resolution by high-resolution X-ray reflectivity measurement. The terminal layer shows a reduced electron density compared to the following substrate lattice layers, which indicates there are additional defects generated by metal depletion as well as intrinsic oxygen vacancies, both of which are apparently filled by water species. Above this top surface layer, two additional adsorbed layers are observed forming a characteristic interfacial hydration structure. The first adsorbed layer shows abnormally high density as pure water and likely includes metal species, whereas the second layer consists of pure water. The observed interfacial hydration structure seems responsible for local equilibration of the defective surface in water and eventually regulating the long-term degradation processes. The multitude of water interactions with the zirconia surface results in the complex but highly ordered interfacial structure constituting the reaction front.
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37
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Petach TA, Mehta A, Marks R, Johnson B, Toney MF, Goldhaber-Gordon D. Voltage-Controlled Interfacial Layering in an Ionic Liquid on SrTiO3. ACS NANO 2016; 10:4565-4569. [PMID: 26959226 DOI: 10.1021/acsnano.6b00645] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
One prominent structural feature of ionic liquids near surfaces is formation of alternating layers of anions and cations. However, how this layering responds to an applied potential is poorly understood. We focus on the structure of 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl) trifluorophosphate (BMPY-FAP) near the surface of a strontium titanate (SrTiO3) electric double-layer transistor. Using X-ray reflectivity, we show that at positive bias the individual layers in the ionic liquid double layer thicken and the layering persists further away from the interface. We model the reflectivity using a modified distorted crystal model with alternating cation and anion layers, which allows us to extract the charge density and the potential near the surface. We find that the charge density is strongly oscillatory with and without applied potential and that with an applied gate bias of 4.5 V the first two layers become significantly more cation rich than at zero bias, accumulating about 2.5 × 10(13) cm(-2) excess charge density.
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Affiliation(s)
- Trevor A Petach
- Department of Physics, Stanford University , Palo Alto, California 94305, United States
| | - Apurva Mehta
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Ronald Marks
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Bart Johnson
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Michael F Toney
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
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38
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Elfassy E, Mastai Y, Pontoni D, Deutsch M. Liquid-Mercury-Supported Langmuir Films of Ionic Liquids: Isotherms, Structure, and Time Evolution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:3164-3173. [PMID: 26963651 DOI: 10.1021/acs.langmuir.6b00196] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ionic liquids have been intensively developed for the last few decades and are now used in a wide range of applications, from electrochemistry to catalysis and nanotechnology. Many of these applications involve ionic liquid interfaces with other liquids and solids, the subnanometric experimental study of which is highly demanding, and has been little studied to date. We present here a study of mercury-supported Langmuir films of imidazolium-based ionic liquids by surface tensiometry and X-ray reflectivity. The charge-delocalized ionic liquids studied here exhibit no 2D lateral order but show diffuse surface-normal electron density profiles exhibiting gradual mercury penetration into the ionic liquid film, and surface-normal structure evolution over a period of hours. The effect of increasing the nonpolar alkyl chain length was also investigated. The results obtained provide insights into the interactions between these ionic liquids and liquid mercury and about the time evolution of the structure and composition of their interface.
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Affiliation(s)
| | | | - Diego Pontoni
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, 38000 Grenoble, France
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39
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Nishi N, Uruga T, Tanida H. Potential dependent structure of an ionic liquid at ionic liquid/water interface probed by x-ray reflectivity measurements. J Electroanal Chem (Lausanne) 2015. [DOI: 10.1016/j.jelechem.2015.11.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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40
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Mezger M, Roth R, Schröder H, Reichert P, Pontoni D, Reichert H. Solid-liquid interfaces of ionic liquid solutions--Interfacial layering and bulk correlations. J Chem Phys 2015; 142:164707. [PMID: 25933784 DOI: 10.1063/1.4918742] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The influence of the polar, aprotic solvent propylene carbonate on the interfacial structure of the ionic liquid (IL) 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate on sapphire was investigated by high-energy x-ray reflectivity. Experiments at solvent concentrations between 17 mol. % and 83 mol. % bridge the gap between diluted electrolytes described by the classical Gouy-Chapman theory and pure ionic liquids. Analysis of our experimental data revealed interfacial profiles comprised of alternating anion and cation enriched regions decaying gradually into the bulk liquid. With increasing solvent concentration, we observed a decrease in correlation length of the interfacial layering structure. At high ion concentrations, solvent molecules were found to accumulate laterally within the layers. By separating like-charged ions, they reduce their Coulomb repulsion. The results are compared with the bulk structure of IL/solvent blends probed by x-ray scattering and predictions from fundamental fluid theory.
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Affiliation(s)
- Markus Mezger
- Institute of Physics, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Roland Roth
- Institute for Theoretical Physics, Eberhard Karls Universität Tübingen, 72076 Tübingen, Germany
| | - Heiko Schröder
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Peter Reichert
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Diego Pontoni
- European Synchrotron Radiation Facility, 38043 Grenoble, France
| | - Harald Reichert
- European Synchrotron Radiation Facility, 38043 Grenoble, France
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41
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Guo C, Wang J, Wang Z, Li J, Guo Y, Tang S. Modified phase-field-crystal model for solid-liquid phase transitions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:013309. [PMID: 26274309 DOI: 10.1103/physreve.92.013309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Indexed: 06/04/2023]
Abstract
A modified phase-field-crystal (PFC) model is proposed to describe solid-liquid phase transitions by reconstructing the correlation function. The effects of fitting parameters of our modified PFC model on the bcc-liquid phase diagram, numerical stability, and solid-liquid interface properties during planar interface growth are examined carefully. The results indicate that the increase of the correlation function peak width at k=k(m) will enhance the stability of the ordered phase, while the increase of peak height at k=0 will narrow the two-phase coexistence region. The third-order term in the free-energy function and the short wave-length of the correlation function have significant influences on the numerical stability of the PFC model. During planar interface growth, the increase of peak width at k=k(m) will decrease the interface width and the velocity coefficient C, but increase the anisotropy of C and the interface free energy. Finally, the feasibility of the modified phase-field-crystal model is demonstrated with a numerical example of three-dimensional dendritic growth of a body-centered-cubic structure.
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Affiliation(s)
- Can Guo
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Jincheng Wang
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Zhijun Wang
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Junjie Li
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Yaolin Guo
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Sai Tang
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
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42
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Wang H, Grant DJ, Burns PC, Na C. Infrared Signature of the Cation-π Interaction between Calcite and Aromatic Hydrocarbons. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:5820-5826. [PMID: 25974679 DOI: 10.1021/acs.langmuir.5b00610] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The cation-π interaction is proposed as an important mechanism for the adsorption of aromatic hydrocarbons having non-zero quadrupole moments by mineral surfaces. Direct evidence supporting such a mechanism is, however, limited. Using the model mineral calcite, we probe the cation-π interaction with adsorbed benzene, toluene, and ethylbenzene (BTE) molecules using attenuated total reflectance Fourier transform infrared spectroscopy. We show that the presence of calcite increases the energy required to excite the synchronized bending of aromatic C-H bonds of BTE molecules. The unique conformation of this vibrational mode indicates that the planar aromatic rings of BTE molecules are constrained in a tilted face-down position by the cation-π interaction, as further confirmed by density functional theory calculations. Our results suggest that the shift of the excitation energy of the aromatic C-H bending may be used as an infrared signature for the cation-π interaction occurring on mineral surfaces.
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Affiliation(s)
- Haitao Wang
- †Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, Indiana 46556, United States
| | - Daniel J Grant
- ‡Department of Chemistry, University of Minnesota, 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Peter C Burns
- †Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, Indiana 46556, United States
- §Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States
| | - Chongzheng Na
- †Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, Indiana 46556, United States
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Brkljača Z, Klimczak M, Miličević Z, Weisser M, Taccardi N, Wasserscheid P, Smith DM, Magerl A, Smith AS. Complementary Molecular Dynamics and X-ray Reflectivity Study of an Imidazolium-Based Ionic Liquid at a Neutral Sapphire Interface. J Phys Chem Lett 2015; 6:549-55. [PMID: 26261977 DOI: 10.1021/jz5024493] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Understanding the molecular-level behavior of ionic liquids (ILs) at IL-solid interfaces is of fundamental importance with respect to their application in, for example, electrochemical systems and electronic devices. Using a model system, consisting of an imidazolium-based IL ([C2Mim][NTf2]) in contact with a sapphire substrate, we have approached this problem using a complementary combination of high-resolution X-ray reflectivity measurements and atomistic molecular dynamics (MD) simulations. Our strategy enabled us to compare experimental and theoretically calculated reflectivities in a direct manner, thereby critically assessing the applicability of several force-field variants. On the other hand, using the best-matching MD description, we are able to describe the nature of the model IL-solid interface in appreciable detail. More specifically, we find that characteristic interactions between the surface hydroxyl groups and donor and acceptor sites on the IL constituents have a dominant role in inducing a multidimensional layering profile of the cations and anions.
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Affiliation(s)
- Zlatko Brkljača
- †Institute for Theoretical Physics, FAU Erlangen-Nürnberg, Staudtstrasse 7, 91058 Erlangen, Germany
| | - Michael Klimczak
- ‡Crystallography and Structural Physics, FAU Erlangen-Nürnberg, Staudtstrasse 3, 91058 Erlangen, Germany
| | - Zoran Miličević
- †Institute for Theoretical Physics, FAU Erlangen-Nürnberg, Staudtstrasse 7, 91058 Erlangen, Germany
| | - Matthias Weisser
- ‡Crystallography and Structural Physics, FAU Erlangen-Nürnberg, Staudtstrasse 3, 91058 Erlangen, Germany
| | - Nicola Taccardi
- §Chemical Reaction Engineering, FAU Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany
| | - Peter Wasserscheid
- §Chemical Reaction Engineering, FAU Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany
| | - David M Smith
- ⊥Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
- ∥Center for Computational Chemistry, FAU Erlangen-Nürnberg, Nägelsbachstrasse 25, 91052 Erlangen, Germany
| | - Andreas Magerl
- ‡Crystallography and Structural Physics, FAU Erlangen-Nürnberg, Staudtstrasse 3, 91058 Erlangen, Germany
| | - Ana-Sunčana Smith
- †Institute for Theoretical Physics, FAU Erlangen-Nürnberg, Staudtstrasse 7, 91058 Erlangen, Germany
- ⊥Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
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Zobel M, Neder RB, Kimber SAJ. Universal solvent restructuring induced by colloidal nanoparticles. Science 2015; 347:292-4. [DOI: 10.1126/science.1261412] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Murphy BM, Greve M, Runge B, Koops CT, Elsen A, Stettner J, Seeck OH, Magnussen OM. A novel X-ray diffractometer for studies of liquid-liquid interfaces. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:45-56. [PMID: 24365915 DOI: 10.1107/s1600577513026192] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 09/22/2013] [Indexed: 06/03/2023]
Abstract
The study of liquid-liquid interfaces with X-ray scattering methods requires special instrumental considerations. A dedicated liquid surface diffractometer employing a tilting double-crystal monochromator in Bragg geometry has been designed. This diffractometer allows reflectivity and grazing-incidence scattering measurements of an immobile mechanically completely decoupled liquid sample, providing high mechanical stability. The available energy range is from 6.4 to 29.4 keV, covering many important absorption edges. The instrument provides access in momentum space out to 2.54 Å(-1) in the surface normal and out to 14.8 Å(-1) in the in-plane direction at 29.4 keV. Owing to its modular design the diffractometer is also suitable for heavy apparatus such as vacuum chambers. The instrument performance is described and examples of X-ray reflectivity studies performed under in situ electrochemical control and on biochemical model systems are given.
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Affiliation(s)
- Bridget M Murphy
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Matthais Greve
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Benjamin Runge
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Christian T Koops
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Annika Elsen
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Jochim Stettner
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Oliver H Seeck
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| | - Olaf M Magnussen
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
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Lü Y, Zhang X, Chen M. Size Effect on Nucleation Rate for Homogeneous Crystallization of Nanoscale Water Film. J Phys Chem B 2013; 117:10241-9. [DOI: 10.1021/jp404403k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yongjun Lü
- School
of Physics, Beijing Institute of Technology, Beijing 100081, P. R. China
| | - Xiangxiong Zhang
- Department
of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
| | - Min Chen
- Department
of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
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Elsen A, Festersen S, Runge B, Koops CT, Ocko BM, Deutsch M, Seeck OH, Murphy BM, Magnussen OM. In situ X-ray studies of adlayer-induced crystal nucleation at the liquid-liquid interface. Proc Natl Acad Sci U S A 2013; 110:6663-8. [PMID: 23553838 PMCID: PMC3637733 DOI: 10.1073/pnas.1301800110] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Crystal nucleation and growth at a liquid-liquid interface is studied on the atomic scale by in situ Å-resolution X-ray scattering methods for the case of liquid Hg and an electrochemical dilute electrolyte containing Pb(2+), F(-), and Br(-) ions. In the regime negative of the Pb amalgamation potential Φ(rp) = -0.70 V, no change is observed from the surface-layered structure of pure Hg. Upon potential-induced release of Pb(2+) from the Hg bulk at Φ > Φ(rp), the formation of an intriguing interface structure is observed, comprising a well-defined 7.6-Å-thick adlayer, decorated with structurally related 3D crystallites. Both are identified by their diffraction peaks as PbFBr, preferentially aligned with their axis along the interface normal. X-ray reflectivity shows the adlayer to consist of a stack of five ionic layers, forming a single-unit-cell-thick crystalline PbFBr precursor film, which acts as a template for the subsequent quasiepitaxial 3D crystal growth. This growth behavior is assigned to the combined action of electrostatic and short-range chemical interactions.
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Affiliation(s)
- Annika Elsen
- Institute for Experimental and Applied Physics, Christian-Albrechts-University Kiel, 24098 Kiel, Germany
| | - Sven Festersen
- Institute for Experimental and Applied Physics, Christian-Albrechts-University Kiel, 24098 Kiel, Germany
| | - Benjamin Runge
- Institute for Experimental and Applied Physics, Christian-Albrechts-University Kiel, 24098 Kiel, Germany
| | - Christian T. Koops
- Institute for Experimental and Applied Physics, Christian-Albrechts-University Kiel, 24098 Kiel, Germany
| | - Benjamin M. Ocko
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973
| | - Moshe Deutsch
- Physics Department, and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Oliver H. Seeck
- Deutsches Elektronensynchrotron DESY, 22607 Hamburg, Germany; and
| | - Bridget M. Murphy
- Institute for Experimental and Applied Physics, Christian-Albrechts-University Kiel, 24098 Kiel, Germany
- Ruprecht Haensel Laboratory, Christian-Albrechts-University Kiel, 24098 Kiel, Germany
| | - Olaf M. Magnussen
- Institute for Experimental and Applied Physics, Christian-Albrechts-University Kiel, 24098 Kiel, Germany
- Ruprecht Haensel Laboratory, Christian-Albrechts-University Kiel, 24098 Kiel, Germany
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Surface layering and melting in an ionic liquid studied by resonant soft X-ray reflectivity. Proc Natl Acad Sci U S A 2013; 110:3733-7. [PMID: 23431181 DOI: 10.1073/pnas.1211749110] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The molecular-scale structure of the ionic liquid [C18mim](+)[FAP](-) near its free surface was studied by complementary methods. X-ray absorption spectroscopy and resonant soft X-ray reflectivity revealed a depth-decaying near-surface layering. Element-specific interfacial profiles were extracted with submolecular resolution from energy-dependent soft X-ray reflectivity data. Temperature-dependent hard X-ray reflectivity, small- and wide-angle X-ray scattering, and infrared spectroscopy uncovered an intriguing melting mechanism for the layered region, where alkyl chain melting drove a negative thermal expansion of the surface layer spacing.
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Calderín L, González LE, González DJ. An ab initio study of the structure and dynamics of bulk liquid Cd and its liquid-vapor interface. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:065102. [PMID: 23334159 DOI: 10.1088/0953-8984/25/6/065102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Several static and dynamic properties of bulk liquid Cd at a thermodynamic state near its triple point have been calculated by means of ab initio molecular dynamics simulations. The calculated static structure shows a very good agreement with the available experimental data. The dynamical structure reveals collective density excitations with an associated dispersion relation which points to a small positive dispersion. Results are also reported for several transport coefficients. Additional simulations have also been performed at a slightly higher temperature in order to study the structure of the free liquid surface. The ionic density profile shows an oscillatory behavior with two different wavelengths, as the spacing between the outer and first inner layer is different from that between the other inner layers. The calculated reflectivity shows a marked maximum whose origin is related to the surface layering, along with a shoulder located at a much smaller wavevector transfer.
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Affiliation(s)
- L Calderín
- Materials Research Institute and Research Computing and Cyberinfrastructure, The Pennsylvania State University, PA 16802, USA.
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