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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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Filippov A, Antzutkin ON. State of anion in ethylammonium nitrate enclosed between micrometer-spaced glass plates as studied by 17O and 15N NMR. Phys Chem Chem Phys 2023; 25:14538-14545. [PMID: 37191082 DOI: 10.1039/d3cp01737k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Some aprotic and protic ionic liquids (ILs) containing nitrate anion demonstrate unusual dynamic behavior of cations when these ILs are enclosed in micrometer-spaced layers between glass plates. We applied 17O and 15N NMR spectroscopy to discover the state and transformations of 17O and 15N isotopically enriched nitrate anion of ethylammonium nitrate (EAN) enclosed between glass plates. 15N NMR spectra demonstrated preferential orientation of the principal axes of the nitrate anions perpendicular to the normal of the glass surface. Therefore, isotropic ionic liquid EAN, when placed within a micrometer-spaced enclosure, forms an ordered phase, which is similar to a liquid crystal. The peculiarity of this phase is that the cations do not have a predominant orientation. Other features of this phase that are typical for liquid crystal phases are the changed local and translational dynamics in comparison with the isotropic state and slow transformation occurring under the action of an external magnetic field.
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Affiliation(s)
- Andrei Filippov
- Chemistry of Interfaces, Luleå University of Technology, SE-97187 Luleå, Sweden.
| | - Oleg N Antzutkin
- Chemistry of Interfaces, Luleå University of Technology, SE-97187 Luleå, Sweden.
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3
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Sloutskin E, Tamam L, Sapir Z, Ocko BM, Bain CD, Kuzmenko I, Gog T, Deutsch M. Counterions under a Surface-Adsorbed Cationic Surfactant Monolayer: Structure and Thermodynamics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:12356-12366. [PMID: 36170153 DOI: 10.1021/acs.langmuir.2c02076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The surface adsorption of ionic surfactants is fundamental for many widespread phenomena in life sciences and for a wide range of technological applications. However, direct atomic-resolution structural experimental studies of noncrystalline surface-adsorbed films are scarce. Thus, even the most central physical aspects of these films, such as their charge density, remain uncertain. Consequently, theoretical models based on contradicting assumptions as for the surface films' ionization are widely used for the description and prediction of surface thermodynamics. We employ X-ray reflectivity to obtain the Ångström-scale surface-normal structure of surface-adsorbed films of the cationic surfactant cetyltrimethylammonium bromide (CTAB) in aqueous solutions at several different temperatures and concentrations. In conjunction with published neutron reflectivity data, we determine the surface-normal charge distribution due to the dissociated surfactants' headgroups. The distribution appears to be inconsistent with the Gouy-Chapman model yet consistent with a compact Stern layer model of condensed counterions. The experimental surfactant adsorption thermodynamics conforms well to classical, Langmuir and Kralchevsky, adsorption models. Furthermore, the Kralchevsky model correctly reproduces the observed condensation of counterions, allowing the values of the adsorption parameters to be resolved, based on the combination of the present data and the published surface tension measurements.
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Affiliation(s)
- Eli Sloutskin
- Physics Department and Bar-Ilan Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Lilach Tamam
- Physics Department and Bar-Ilan Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Zvi Sapir
- Physics Department and Bar-Ilan Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Benjamin M Ocko
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Colin D Bain
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE, U.K
| | - Ivan Kuzmenko
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Thomas Gog
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Moshe Deutsch
- Physics Department and Bar-Ilan Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
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4
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Purcell SM, Lane PD, D'Andrea L, Elstone NS, Bruce DW, Slattery JM, Smoll EJ, Greaves SJ, Costen ML, Minton TK, McKendrick KG. Surface Structure of Alkyl/Fluoroalkylimidazolium Ionic-Liquid Mixtures. J Phys Chem B 2022; 126:1962-1979. [PMID: 35225614 PMCID: PMC9007465 DOI: 10.1021/acs.jpcb.1c10460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The gas-liquid interface of ionic liquids (ILs) is critically important in many applications, for example, in supported IL phase (SILP) catalysis. Methods to investigate the interfacial structure in these systems will allow their performance to be improved in a rational way. In this study, reactive-atom scattering (RAS), surface tension measurements, and molecular dynamics (MD) simulations were used to study the vacuum interface of mixtures of partially fluorinated and normal alkyl ILs. The underlying aim was to understand whether fluorinated IL ions could be used as additives to modify the surface structure of one of the most widely used families of alkyl ILs. The series of ILs 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Cnmim][Tf2N]) with n = 4-12 were mixed with a fixed-length, semiperfluorinated analogue (1H,1H,2H,2H-perfluorooctyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C8mimF13][Tf2N]), forming [Cnmim](1-x)[C8mimF13]x[Tf2N] mixtures, where x is the bulk mole fraction of the fluorinated component. The RAS-LIF method combined O-atom projectiles with laser-induced fluorescence (LIF) detection of the product OH as a measure of surface exposure of the alkyl chains. For [C8mim](1-x)[C8mimF13]x[Tf2N] mixtures, RAS-LIF OH yields are below those expected from stoichiometry. There are quantitatively consistent negative deviations from linearity of the surface tension. Both results imply that the lower-surface-tension fluoroalkyl material dominates the surface. A similar deficit is found for alkyl chain lengths n = 4, 6, 8, and 12 and for all (nonzero) x investigated by RAS-LIF. Accessible-surface-area (ASA) analyses of the MD simulations for [Cnmim](1-x)[C8mimF13]x[Tf2N] mixtures qualitatively reproduce the same primary effect of fluoro-chain predominance of the surface over most of the range of n. However, there are significant quantitative discrepancies between MD ASA predictions and experiment relating to the strength of any n-dependence of the relative alkyl coverage at fixed x, and on the x-dependence at fixed n. These discrepancies are discussed in the context of detailed examinations of the surface structures predicted in the MD simulations. Potential explanations, beyond experimental artifacts, include inadequacies in the classical force fields used in the MD simulations or the inability of simple ASA algorithms to capture dynamical factors that influence RAS-LIF yields.
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Affiliation(s)
- Simon M Purcell
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Paul D Lane
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Lucía D'Andrea
- Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
| | - Naomi S Elstone
- Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
| | - Duncan W Bruce
- Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
| | - John M Slattery
- Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
| | - Eric J Smoll
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Stuart J Greaves
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Matthew L Costen
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Timothy K Minton
- Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Kenneth G McKendrick
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
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5
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Nemoto F, Nakamura SY, Abe H. Surface structure of the mixture of 1-alkyl-3-methylimidazolium iodide and polyiodide observed by surface tension measurement and X-ray reflectivity. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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6
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Voegtle MJ, Pal T, Pennathur AK, Menachekanian S, Patrow JG, Sarkar S, Cui Q, Dawlaty JM. Interfacial Polarization and Ionic Structure at the Ionic Liquid-Metal Interface Studied by Vibrational Spectroscopy and Molecular Dynamics Simulations. J Phys Chem B 2021; 125:2741-2753. [PMID: 33689335 DOI: 10.1021/acs.jpcb.0c11232] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ionic liquids (ILs) have both fundamental and practical value in interfacial science and electrochemistry. However, understanding their behavior near a surface is challenging because of strong Coulomb interactions and large and irregular ionic sizes, which affect both their structure and energetics. To understand this problem, we present a combined experimental and computational study using a vibrational probe molecule, 4-mercaptobenzonitrile, inserted at the junction between a metal and a variety of ILs. The vibrational frequency of the nitrile in the probe molecule reports on the local solvation environment and the electrostatic field at this junction. Within the ethylmethyl imidazolium (EMIM+) cation family of ILs, we varied the anions over a range of sizes and types. Complementing our surface spectroscopy, we also ran molecular dynamics simulations of these interfaces to better understand the ionic structures that produced the measured fields. The magnitude of the frequency shifts, and thereby fields, shows a general correlation with the size of anions, with larger anions corresponding to smaller fields. We find that the source of this correlation is partial intercalation of smaller anions into the probe monolayer, resulting in tighter packing of ionic layers near the surface. Larger anions reduce the overall lateral ion packing density near the surface, which reduces the net charge per unit area and explains the smaller observed fields. The insight from this work is important for developing a fundamental picture of concentrated electrolytes near interfaces and can help with designing ILs to create tailored electric fields near an electrode.
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Affiliation(s)
- Matthew J Voegtle
- Department of Chemistry, University of Southern California, Los Angeles, California 90007, United States
| | - Tanmoy Pal
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Anuj K Pennathur
- Department of Chemistry, University of Southern California, Los Angeles, California 90007, United States
| | - Sevan Menachekanian
- Department of Chemistry, University of Southern California, Los Angeles, California 90007, United States
| | - Joel G Patrow
- Department of Chemistry, University of Southern California, Los Angeles, California 90007, United States
| | - Sohini Sarkar
- Department of Chemistry, University of Southern California, Los Angeles, California 90007, United States
| | - Qiang Cui
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Jahan M Dawlaty
- Department of Chemistry, University of Southern California, Los Angeles, California 90007, United States
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7
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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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8
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Wang YL, Li B, Sarman S, Mocci F, Lu ZY, Yuan J, Laaksonen A, Fayer MD. Microstructural and Dynamical Heterogeneities in Ionic Liquids. Chem Rev 2020; 120:5798-5877. [PMID: 32292036 PMCID: PMC7349628 DOI: 10.1021/acs.chemrev.9b00693] [Citation(s) in RCA: 189] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation-anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
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Affiliation(s)
- Yong-Lei Wang
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Bin Li
- School
of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China
| | - Sten Sarman
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Francesca Mocci
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy
| | - Zhong-Yuan Lu
- State
Key Laboratory of Supramolecular Structure and Materials, Institute
of Theoretical Chemistry, Jilin University, Changchun 130021, P. R. China
| | - Jiayin Yuan
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Aatto Laaksonen
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
- State
Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
- Centre of
Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry Aleea Grigore Ghica-Voda, 41A, 700487 Iasi, Romania
- Department
of Engineering Sciences and Mathematics, Division of Energy Science, Luleå University of Technology, SE-97187 Luleå, Sweden
| | - Michael D. Fayer
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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9
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Iwahashi T, Ishiyama T, Sakai Y, Morita A, Kim D, Ouchi Y. Bi-layering at ionic liquid surfaces: a sum-frequency generation vibrational spectroscopy- and molecular dynamics simulation-based study. Phys Chem Chem Phys 2020; 22:12565-12576. [PMID: 32452479 DOI: 10.1039/d0cp01219j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Room-temperature ionic liquids (RTILs) are being increasingly employed as novel solvents in several fields, including chemical engineering, electrochemistry, and synthetic chemistry. To further increase their usage potential, a better understanding of the structure of their surface layer is essential. Bi-layering at the surfaces of RTILs consisting of 1-alkyl-3-methylimidazolium ([Cnmim]+; n = 4, 6, 8, 10, and 12) cations and bis(trifluoromethanesulfonyl)amide ([TFSA]-) anions was demonstrated via infrared-visible sum-frequency generation (IV-SFG) vibrational spectroscopy and molecular dynamics (MD) simulations. It was found that the sum-frequency (SF) signal from the [TFSA]- anions decreases as the alkyl chain length increases, whereas the SF signal from the r+ mode (the terminal CH3 group) of the [Cnmim]+ cations is almost the same regardless of chain length. MD simulations show the formation of a bi-layered structure consisting of the outermost first layer and a submerged second layer in a "head-to-head" molecular arrangement. The decrease in the SF signals of the normal modes of the [TFSA]- anions is caused by destructive and out-of-phase interference of vibrations of corresponding molecular moieties oriented toward each other in the first and second layers. In contrast, the r+ mode of [Cnmim]+ does not experience destructive interference because the peak position of the r+ mode differs marginally at the surface and in the bulk. Our conclusions are not limited to the system presented here. Similar bi-layered structures can be expected for the surfaces of conventional RTILs, which necessitates the consideration of bi-layering in the design and application.
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Affiliation(s)
- Takashi Iwahashi
- Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8552, Japan.
| | - Tatsuya Ishiyama
- Department of Environmental Applied Chemistry, Faculty of Engineering, University of Toyama, Gofuku, Toyama-shi, Toyama 930-8555, Japan
| | - Yasunari Sakai
- Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8552, Japan.
| | - Akihiro Morita
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai, 980-8578, Japan.,Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Kyoto 615-8520, Japan
| | - Doseok Kim
- Department of Physics, Sogang University, Seoul, 04107, Republic of Korea
| | - Yukio Ouchi
- Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8552, Japan.
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11
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Black JM, Zhu M, Zhang P, Unocic RR, Guo D, Okatan MB, Dai S, Cummings PT, Kalinin SV, Feng G, Balke N. Fundamental aspects of electric double layer force-distance measurements at liquid-solid interfaces using atomic force microscopy. Sci Rep 2016; 6:32389. [PMID: 27587276 PMCID: PMC5009352 DOI: 10.1038/srep32389] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 08/03/2016] [Indexed: 11/09/2022] Open
Abstract
Atomic force microscopy (AFM) force-distance measurements are used to investigate the layered ion structure of Ionic Liquids (ILs) at the mica surface. The effects of various tip properties on the measured force profiles are examined and reveal that the measured ion position is independent of tip properties, while the tip radius affects the forces required to break through the ion layers as well as the adhesion force. Force data is collected for different ILs and directly compared with interfacial ion density profiles predicted by molecular dynamics. Through this comparison it is concluded that AFM force measurements are sensitive to the position of the ion with the larger volume and mass, suggesting that ion selectivity in force-distance measurements are related to excluded volume effects and not to electrostatic or chemical interactions between ions and AFM tip. The comparison also revealed that at distances greater than 1 nm the system maintains overall electroneutrality between the AFM tip and sample, while at smaller distances other forces (e.g., van der waals interactions) dominate and electroneutrality is no longer maintained.
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Affiliation(s)
- Jennifer M Black
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Mengyang Zhu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Pengfei Zhang
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Raymond R Unocic
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Daqiang Guo
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - M Baris Okatan
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Sheng Dai
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Peter T Cummings
- Department of Chemical &Biomolecular Engineering and Multiscale Modeling and Simulation Center, Vanderbilt University, Nashville, TN, 37235, USA
| | - Sergei V Kalinin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Guang Feng
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Nina Balke
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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12
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Nakajima K, Nakanishi S, Lísal M, Kimura K. Surface structure of imidazolium-based ionic liquids: Quantitative comparison between simulations and high-resolution RBS measurements. J Chem Phys 2016; 144:114702. [PMID: 27004888 DOI: 10.1063/1.4943887] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Elemental depth profiles of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([CnMIM][TFSI], n = 4, 6, 8) are measured using high-resolution Rutherford backscattering spectroscopy (HRBS). The profiles are compared with the results of molecular dynamics (MD) simulations. Both MD simulations and HRBS measurements show that the depth profiles deviate from the uniform stoichiometric composition in the surface region, showing preferential orientations of ions at the surface. The MD simulations qualitatively reproduce the observed HRBS profiles but the agreement is not satisfactory. The observed discrepancy is ascribed to the capillary waves. By taking account of the surface roughness induced by the capillary waves, the agreement becomes almost perfect.
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Affiliation(s)
- Kaoru Nakajima
- Department of Micro Engineering, Kyoto University, Kyoto-daigaku-katsura, Nishikyo, Kyoto 615-8540, Japan
| | - Shunto Nakanishi
- Department of Micro Engineering, Kyoto University, Kyoto-daigaku-katsura, Nishikyo, Kyoto 615-8540, Japan
| | - Martin Lísal
- Laboratory of Aerosols Chemistry and Physics, Institute of Chemical Process Fundamentals of the CAS, v. v. i., Suchdol, Prague 6 165 02, Czech Republic
| | - Kenji Kimura
- Department of Micro Engineering, Kyoto University, Kyoto-daigaku-katsura, Nishikyo, Kyoto 615-8540, Japan
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13
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Liu YS, Cai CY, Sha ML. Molecular dynamics simulations of the ionic liquid [BMIM][PF6] confined inside silicon slit nanopores. RUSS J APPL CHEM+ 2015. [DOI: 10.1134/s1070427215090244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Konieczny JK, Szefczyk B. Structure of Alkylimidazolium-Based Ionic Liquids at the Interface with Vacuum and Water—A Molecular Dynamics Study. J Phys Chem B 2015; 119:3795-807. [DOI: 10.1021/jp510843m] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jan K. Konieczny
- Advanced Materials Engineering and Modelling Group, Faculty of Chemistry, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Borys Szefczyk
- Advanced Materials Engineering and Modelling Group, Faculty of Chemistry, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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Khatun S, Castner EW. Ionic Liquid–Solute Interactions Studied by 2D NOE NMR Spectroscopy. J Phys Chem B 2014; 119:9225-35. [DOI: 10.1021/jp509861g] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Sufia Khatun
- Department of Chemistry and
Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Edward W. Castner
- Department of Chemistry and
Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
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16
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Affiliation(s)
- Maxim V Fedorov
- Department of Physics, Scottish University Physics Alliance (SUPA), University of Strathclyde , John Anderson Bldg, 107 Rottenrow, Glasgow, G4 0NG United Kingdom
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17
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Chen S, Zhang S, Liu X, Wang J, Wang J, Dong K, Sun J, Xu B. Ionic liquid clusters: structure, formation mechanism, and effect on the behavior of ionic liquids. Phys Chem Chem Phys 2014; 16:5893-906. [DOI: 10.1039/c3cp53116c] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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18
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Villar-Garcia IJ, Fearn S, De Gregorio GF, Ismail NL, Gschwend FJV, McIntosh AJS, Lovelock KRJ. The ionic liquid–vacuum outer atomic surface: a low-energy ion scattering study. Chem Sci 2014. [DOI: 10.1039/c4sc00640b] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have identified elements present in the ionic liquid–vacuum outer atomic surface of 23 ionic liquids using high sensitivity low-energy ion scattering (LEIS), a very surface sensitive technique.
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Affiliation(s)
| | - Sarah Fearn
- Department of Materials
- Imperial College London
- , UK
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19
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Elola MD, Rodriguez J. Structure and dynamics of nonionic surfactants adsorbed at vacuum/ionic liquid interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:13379-13387. [PMID: 24156286 DOI: 10.1021/la402683j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Structural and dynamical properties related to the adsorption of nonionic surfactants at vacuum/ionic liquid interfaces were studied using molecular dynamics simulations. Specifically, the surface activity of pentaethylene glycol monododecyl ether (C12E5) was investigated at the free interface of an imidazolium-based room temperature ionic liquid (RTIL), at different surface densities. At low surface coverages, the incorporation of C12E5 does not produce meaningful changes in the vacuum/RTIL interface: the C12E5 hydrophobic tails remain entangled with those of the RTIL cation groups in the outer shell, whereas the C12E5 hydrophilic heads reside at an inner layer. At high surface coverages, the structure in the substrate-in terms of the features exhibited by the local density profiles-practically vanishes; the interface becomes wider and the surfactant molecules shift toward more external positions. Information about the local structure of the interface at high surface densities can be recovered by performing a tessellation procedure. For the sake of comparison, the surface behavior of two commonly used ionic surfactants, sodium dodecyl sulfate and dodecyl trimethyl ammonium chloride, were also studied. The modifications in the width and structure of the bare vacuum/RTIL interface due to the presence of the ionic surfactants are markedly milder than those observed for the nonionic surfactant. Moreover, the RTIL seemed to behave as a better solvent for the chloride counterions than for sodium ones; which were found to remain bound to the surfactant head groups. An analysis of the dynamics at the surface was also performed. Our results indicate that the presence of increasing amounts of nonionic surfactants leads to a gradual reduction of the mobility of the RTIL species. When ionic surfactants are adsorbed, these retardations are even more severe for the surfactant head groups, where the corresponding diffusion coefficients show reductions of practically 1 order of magnitude.
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Affiliation(s)
- M Dolores Elola
- Departamento de Física, Comisión Nacional de Energía Atómica , Avenida Libertador 8250, 1429 Buenos Aires, Argentina , and
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20
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Chang TM, Dang LX. Computational studies of [bmim][PF6]/n-alcohol interfaces with many-body potentials. J Phys Chem A 2013; 118:7186-93. [PMID: 24063438 DOI: 10.1021/jp405910k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In this paper, we present the results from molecular dynamics simulations of the equilibrium properties of liquid/liquid interfaces of room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and simple alcohols (i.e., methanol, 1-butanol, and 1-hexanol) at room temperature. Polarizable potential models are employed to describe the interactions among species. Results from our simulations show stable interfaces between the ionic liquid and n-alcohols, and we found that the interfacial widths decrease from methanol to 1-butanol systems and then increase for 1-hexanol interfaces. Angular distribution analysis reveals that the interface induces a strong orientational order of [bmim] and n-alcohol molecules near the interface, with [bmim] extending its butyl group into the alcohol phase, whereas the alcohol has the OH group pointing into the ionic liquid region, which is consistent with the recent sum-frequency-generation experiments. We found the interface to have a significant influence on the dynamics of ionic liquids and n-alcohols. The orientational autocorrelation functions illustrate that [bmim] rotates more freely near the interface than in the bulk, whereas the rotation of n-alcohol is hindered at the interface. Additionally, the time scale associated with the diffusion along the interfacial direction is found to be faster for [bmim] but slowed down for n-alcohols approaching the interface. We also calculate the dipole moment of n-alcohols as a function of the distance normal to the interface. We found that, even though methanol and 1-butanol have different dipole moments in bulk phase, they reach a similar value at the interface.
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Affiliation(s)
- Tsun-Mei Chang
- Department of Chemistry, University of Wisconsin , Parkside, Wisconsin 53141, United States
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21
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Molecular dynamics study of ionic liquid film based on [emim][Tf2N] and [emim][TfO] adsorbed on highly oriented pyrolytic graphite. Chem Res Chin Univ 2013. [DOI: 10.1007/s40242-013-2082-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Wang YL, Laaksonen A, Lu ZY. Influence of ionic liquid film thickness on ion pair distributions and orientations at graphene and vacuum interfaces. Phys Chem Chem Phys 2013; 15:13559-69. [DOI: 10.1039/c3cp51226f] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Cummings OT, Wick CD. Computational study on the effect of alkyl chain length on alkane–water interfacial width. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2012.11.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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24
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Ridings C, Lockett V, Andersson G. Comparing the charge distribution along the surface normal in the [C6mim]+ ionic liquid with different anions. Colloids Surf A Physicochem Eng Asp 2012. [DOI: 10.1016/j.colsurfa.2012.01.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Embs JP, Burankova T, Reichert E, Hempelmann R. Cation dynamics in the pyridinium based ionic liquid 1-N-butylpyridinium bis((trifluoromethyl)sulfonyl) as seen by quasielastic neutron scattering. J Phys Chem B 2012; 116:13265-71. [PMID: 23020511 DOI: 10.1021/jp3070344] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Quasielastic neutron scattering (QENS) has been used to study the cation dynamics in the pyridinium based ionic liquid (IL) 1-N-butylpyridinium bis((trifluoromethyl)sulfonyl)imide (BuPy-Tf(2)N). This IL allows for a detailed investigation of the dynamics of the cations only, due to the huge incoherent scattering cross section of the cation (σ(inc)(cation) >> σ(inc)(anion)). The measured spectra can be decomposed into two Lorentzian lines, indicative of two distinct dynamic processes. The slower of these two processes is diffusive in nature, whereas the faster one can be attributed to localized motions. The temperature dependence of the diffusion coefficient of the slow process follows an Arrhenius law, with an activation energy of E(A) = 14.8 ± 0.3 kJ/mol. Furthermore, we present here results from experiments with polarized neutrons. These experiments clearly show that the slower of the two observed processes is coherent, while the faster one is incoherent in nature.
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Affiliation(s)
- Jan P Embs
- Laboratory for Neutron Scattering, Paul Scherrer Institut, Villigen-PSI, Switzerland.
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26
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Lovelock KRJ. Influence of the ionic liquid/gas surface on ionic liquid chemistry. Phys Chem Chem Phys 2012; 14:5071-89. [PMID: 22349469 DOI: 10.1039/c2cp23851a] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Applications such as gas storage, gas separation, NP synthesis and supported ionic liquid phase catalysis depend upon the interaction of different species with the ionic liquid/gas surface. Consequently, these applications cannot proceed to the full extent of their potential without a profound understanding of the surface structure and properties. As a whole, this perspective contains more questions than answers, which demonstrates the current state of the field. Throughout this perspective, crucial questions are posed and a roadmap is proposed to answer these questions. A critical analysis is made of the field of ionic liquid/gas surface structure and properties, and a number of design rules are mined. The effects of ionic additives on the ionic liquid/gas surface structure are presented. A possible driving force for surface formation is discussed that has, to the best of my knowledge, not been postulated in the literature to date. This driving force suggests that for systems composed solely of ions, the rules for surface formation of dilute electrolytes do not apply. The interaction of neutral additives with the ionic liquid/gas surface is discussed. Particular attention is focussed upon H(2)O and CO(2), vital additives for many applications of ionic liquids. Correlations between ionic liquid/gas surface structure and properties, ionic liquid surfaces plus additives, and ionic liquid applications are given.
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Affiliation(s)
- Kevin R J Lovelock
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK.
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27
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Tariq M, Freire MG, Saramago B, Coutinho JAP, Lopes JNC, Rebelo LPN. Surface tension of ionic liquids and ionic liquid solutions. Chem Soc Rev 2011; 41:829-68. [PMID: 21811714 DOI: 10.1039/c1cs15146k] [Citation(s) in RCA: 228] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Some of the most active scientific research fronts of the past decade are centered on ionic liquids. These fluids present characteristic surface behavior and distinctive trends of their surface tension versus temperature. One way to explore and understand their unique nature is to study their surface properties. This critical review analyses most of the surface tension data reported between 2001 and 2010 (187 references).
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Affiliation(s)
- Mohammad Tariq
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. República, Apt. 127, 2780-901 Oeiras, Portugal
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28
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Waring C, Bagot PAJ, Costen ML, McKendrick KG. Reactive Scattering as a Chemically Specific Analytical Probe of Liquid Surfaces. J Phys Chem Lett 2011; 2:12-18. [PMID: 26295207 DOI: 10.1021/jz1013032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this Perspective, we highlight some recent progress in the reactive scattering of "chemical probe" species such as atoms or small radicals from liquid surfaces. We emphasize in particular the evolution of this area from purely dynamical studies of the scattering mechanism. The mechanistic understanding that has now been gained is sufficiently mature to allow the same methods to be used as an effective analytical tool. The use of this approach to measure liquid-surface composition and structure is illustrated through the scattering of O((3)P) atoms from a common, imidazolium-based family of ionic liquids.
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Affiliation(s)
- Carla Waring
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Paul A J Bagot
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Matthew L Costen
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Kenneth G McKendrick
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
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29
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Pensado AS, Gomes MFC, Lopes JNC, Malfreyt P, Pádua AAH. Effect of alkyl chain length and hydroxyl group functionalization on the surface properties of imidazolium ionic liquids. Phys Chem Chem Phys 2011; 13:13518-26. [DOI: 10.1039/c1cp20563c] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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30
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Ridings C, Lockett V, Andersson G. Effect of the aliphatic chain length on electrical double layer formation at the liquid/vacuum interface in the [Cnmim][BF4] ionic liquid series. Phys Chem Chem Phys 2011; 13:17177-84. [DOI: 10.1039/c1cp20910h] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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31
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Sarangi SS, Raju SG, Balasubramanian S. Molecular dynamics simulations of ionic liquid–vapour interfaces: effect of cation symmetry on structure at the interface. Phys Chem Chem Phys 2011; 13:2714-22. [DOI: 10.1039/c0cp01272f] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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32
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Chen LG, Lerum RV, Aranda-Espinoza H, Bermudez H. Surfactant-Mediated Ion Exchange and Charge Reversal at Ionic Liquid Interfaces. J Phys Chem B 2010; 114:11502-8. [DOI: 10.1021/jp106582t] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lang G. Chen
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts, and Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Ronald V. Lerum
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts, and Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Helim Aranda-Espinoza
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts, and Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Harry Bermudez
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts, and Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
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33
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Sun B, Wu P. Trace of the Thermally Induced Evolution Mechanism of Interactions Between Water and Ionic Liquids. J Phys Chem B 2010; 114:9209-19. [DOI: 10.1021/jp1041525] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bingjie Sun
- The Key Laboratory of Molecular Engineering of Polymers (Ministry of Education) and Department of Macromolecular Science and Advanced Materials Laboratory, Fudan University, Shanghai 200433, PR China
| | - Peiyi Wu
- The Key Laboratory of Molecular Engineering of Polymers (Ministry of Education) and Department of Macromolecular Science and Advanced Materials Laboratory, Fudan University, Shanghai 200433, PR China
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34
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Heggen B, Zhao W, Leroy F, Dammers AJ, Müller-Plathe F. Interfacial Properties of an Ionic Liquid by Molecular Dynamics. J Phys Chem B 2010; 114:6954-61. [DOI: 10.1021/jp911128j] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Berit Heggen
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, 64287 Darmstadt, Germany, Max-Planck-Insitut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Biometris — Applied Statistics, Wageningen University, P.O. Box 100, 6700 AC Wageningen, The Netherlands
| | - Wei Zhao
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, 64287 Darmstadt, Germany, Max-Planck-Insitut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Biometris — Applied Statistics, Wageningen University, P.O. Box 100, 6700 AC Wageningen, The Netherlands
| | - Frédéric Leroy
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, 64287 Darmstadt, Germany, Max-Planck-Insitut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Biometris — Applied Statistics, Wageningen University, P.O. Box 100, 6700 AC Wageningen, The Netherlands
| | - Anton J. Dammers
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, 64287 Darmstadt, Germany, Max-Planck-Insitut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Biometris — Applied Statistics, Wageningen University, P.O. Box 100, 6700 AC Wageningen, The Netherlands
| | - Florian Müller-Plathe
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, 64287 Darmstadt, Germany, Max-Planck-Insitut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Biometris — Applied Statistics, Wageningen University, P.O. Box 100, 6700 AC Wageningen, The Netherlands
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Waring C, Bagot PAJ, Slattery JM, Costen ML, McKendrick KG. O(3P) Atoms as a Chemical Probe of Surface Ordering in Ionic Liquids. J Phys Chem A 2010; 114:4896-904. [DOI: 10.1021/jp912045j] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Carla Waring
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Paul A. J. Bagot
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - John M. Slattery
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Matthew L. Costen
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Kenneth G. McKendrick
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
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37
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Santos CS, Baldelli S. Gas-liquid interface of room-temperature ionic liquids. Chem Soc Rev 2010; 39:2136-45. [PMID: 20502802 DOI: 10.1039/b921580h] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The organization of ions at the interface of ionic liquids and the vacuum is an ideal system to test new ideas and concepts on the interfacial chemistry of electrolyte systems in the limit of no solvent medium. Whilst electrolyte systems have numerous theoretical and experimental methods used to investigate their properties, the ionic liquids are relatively new and our understanding of the interfacial properties is just beginning to be explored. In this critical review, the gas-liquid interface is reviewed, as this interface does not depend on the preparation of another medium and thus produces a natural interface. The interface has been investigated by sum frequency generation vibrational spectroscopy and ultra-high vacuum techniques. The results provide a detailed molecular-level view of the surface composition and structure. These have been complemented by theoretical studies. The combinations of treatments on this interface are starting to provide a somewhat convergent description of how the ions are organized at this neat interface (108 references).
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Affiliation(s)
- Cherry S Santos
- University of Houston, Department of Chemistry, Houston, TX 77204-5003, USA
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38
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Kislenko SA, Amirov RH, Samoylov IS. Influence of temperature on the structure and dynamics of the [BMIM][PF6] ionic liquid/graphite interface. Phys Chem Chem Phys 2010; 12:11245-50. [DOI: 10.1039/c0cp00220h] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Zhao W, Leroy F, Heggen B, Zahn S, Kirchner B, Balasubramanian S, Müller-Plathe F. Are There Stable Ion-Pairs in Room-Temperature Ionic Liquids? Molecular Dynamics Simulations of 1-n-Butyl-3-methylimidazolium Hexafluorophosphate. J Am Chem Soc 2009; 131:15825-33. [DOI: 10.1021/ja906337p] [Citation(s) in RCA: 249] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wei Zhao
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, D-64287 Darmstadt, Germany, Wilhelm-Ostwald Institute of Physical and Theoretical Chemistry, University of Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - Frédéric Leroy
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, D-64287 Darmstadt, Germany, Wilhelm-Ostwald Institute of Physical and Theoretical Chemistry, University of Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - Berit Heggen
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, D-64287 Darmstadt, Germany, Wilhelm-Ostwald Institute of Physical and Theoretical Chemistry, University of Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - Stefan Zahn
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, D-64287 Darmstadt, Germany, Wilhelm-Ostwald Institute of Physical and Theoretical Chemistry, University of Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - Barbara Kirchner
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, D-64287 Darmstadt, Germany, Wilhelm-Ostwald Institute of Physical and Theoretical Chemistry, University of Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - Sundaram Balasubramanian
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, D-64287 Darmstadt, Germany, Wilhelm-Ostwald Institute of Physical and Theoretical Chemistry, University of Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - Florian Müller-Plathe
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, D-64287 Darmstadt, Germany, Wilhelm-Ostwald Institute of Physical and Theoretical Chemistry, University of Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
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40
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Sun X, Wick CD, Dang LX. Computational Studies of Aqueous Interfaces of SrCl2 Salt Solutions. J Phys Chem B 2009; 113:13993-7. [DOI: 10.1021/jp9079525] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiuquan Sun
- Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, and Chemistry Department, Louisiana Tech University, Ruston, Louisiana 71270
| | - Collin D. Wick
- Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, and Chemistry Department, Louisiana Tech University, Ruston, Louisiana 71270
| | - Liem X. Dang
- Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, and Chemistry Department, Louisiana Tech University, Ruston, Louisiana 71270
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41
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Souda R. Phase Transition of 1-Ethyl-3-Methylimidazolium Bis(trifluoromethylsulfonyl)imide Thin Films on Highly Oriented Pyrolytic Graphite. J Phys Chem B 2009; 113:12973-7. [DOI: 10.1021/jp9049439] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Ryutaro Souda
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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42
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Ohno A, Hashimoto H, Nakajima K, Suzuki M, Kimura K. Observation of surface structure of 1-butyl-3-methylimidazolium hexafluorophosphate using high-resolution Rutherford backscattering spectroscopy. J Chem Phys 2009; 130:204705. [DOI: 10.1063/1.3141385] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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43
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Santos CS, Baldelli S. Alkyl Chain Interaction at the Surface of Room Temperature Ionic Liquids: Systematic Variation of Alkyl Chain Length (R = C1−C4, C8) in both Cation and Anion of [RMIM][R−OSO3] by Sum Frequency Generation and Surface Tension. J Phys Chem B 2009; 113:923-33. [DOI: 10.1021/jp807924g] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Cherry S. Santos
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003
| | - Steven Baldelli
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003
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Kislenko SA, Samoylov IS, Amirov RH. Molecular dynamics simulation of the electrochemical interface between a graphite surface and the ionic liquid [BMIM][PF6]. Phys Chem Chem Phys 2009; 11:5584-90. [DOI: 10.1039/b823189c] [Citation(s) in RCA: 222] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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45
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Lauw Y, Horne MD, Rodopoulos T, Webster NAS, Minofar B, Nelson A. X-Ray reflectometry studies on the effect of water on the surface structure of [C4mpyr][NTf2] ionic liquid. Phys Chem Chem Phys 2009; 11:11507-14. [DOI: 10.1039/b916046a] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Mezger M, Schramm S, Schröder H, Reichert H, Deutsch M, De Souza EJ, Okasinski JS, Ocko BM, Honkimäki V, Dosch H. Layering of [BMIM][sup +]-based ionic liquids at a charged sapphire interface. J Chem Phys 2009; 131:094701. [DOI: 10.1063/1.3212613] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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47
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Sun B, Jin Q, Tan L, Wu P, Yan F. Trace of the Interesting “V”-Shaped Dynamic Mechanism of Interactions between Water and Ionic Liquids. J Phys Chem B 2008; 112:14251-9. [DOI: 10.1021/jp806805r] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bingjie Sun
- The Key Laboratory of Molecular Engineering of Polymers (Ministry of Education) and Department of Macromolecular Science and Advanced Materials Laboratory, Fudan University, Shanghai 200433, PR China, and Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215123, PR China
| | - Qiu Jin
- The Key Laboratory of Molecular Engineering of Polymers (Ministry of Education) and Department of Macromolecular Science and Advanced Materials Laboratory, Fudan University, Shanghai 200433, PR China, and Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215123, PR China
| | - Lisha Tan
- The Key Laboratory of Molecular Engineering of Polymers (Ministry of Education) and Department of Macromolecular Science and Advanced Materials Laboratory, Fudan University, Shanghai 200433, PR China, and Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215123, PR China
| | - Peiyi Wu
- The Key Laboratory of Molecular Engineering of Polymers (Ministry of Education) and Department of Macromolecular Science and Advanced Materials Laboratory, Fudan University, Shanghai 200433, PR China, and Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215123, PR China
| | - Feng Yan
- The Key Laboratory of Molecular Engineering of Polymers (Ministry of Education) and Department of Macromolecular Science and Advanced Materials Laboratory, Fudan University, Shanghai 200433, PR China, and Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215123, PR China
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48
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Hapiot P, Lagrost C. Electrochemical Reactivity in Room-Temperature Ionic Liquids. Chem Rev 2008; 108:2238-64. [DOI: 10.1021/cr0680686] [Citation(s) in RCA: 996] [Impact Index Per Article: 62.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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49
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Zhao W, Leroy F, Balasubramanian S, Müller-Plathe F. Shear Viscosity of the Ionic Liquid 1-n-Butyl 3-Methylimidazolium Hexafluorophosphate [bmim][PF6] Computed by Reverse Nonequilibrium Molecular Dynamics. J Phys Chem B 2008; 112:8129-33. [DOI: 10.1021/jp8017869] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wei Zhao
- Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, D-64287, Germany, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - Frédéric Leroy
- Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, D-64287, Germany, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - Sundaram Balasubramanian
- Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, D-64287, Germany, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - Florian Müller-Plathe
- Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 20, D-64287, Germany, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
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50
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Maolin S, Fuchun Z, Guozhong W, Haiping F, Chunlei W, Shimou C, Yi Z, Jun H. Ordering layers of [bmim][PF6] ionic liquid on graphite surfaces: Molecular dynamics simulation. J Chem Phys 2008; 128:134504. [DOI: 10.1063/1.2898497] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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