1
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Shen C, Zhang H, Ocko BM. Reconstructing the reflectivity of liquid surfaces from grazing incidence X-ray off-specular scattering data. J Appl Crystallogr 2024; 57:714-727. [PMID: 38846761 PMCID: PMC11151673 DOI: 10.1107/s1600576724002887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Accepted: 04/01/2024] [Indexed: 06/09/2024] Open
Abstract
The capillary wave model of a liquid surface predicts both the X-ray specular reflection and the diffuse scattering around it. A quantitative method is presented to obtain the X-ray reflectivity (XRR) from a liquid surface through the diffuse scattering data around the specular reflection measured using a grazing incidence X-ray off-specular scattering (GIXOS) geometry at a fixed horizontal offset angle with respect to the plane of incidence. With this approach the entire Qz -dependent reflectivity profile can be obtained at a single, fixed incident angle. This permits a much faster acquisition of the profile than with conventional reflectometry, where the incident angle must be scanned point by point to obtain a Qz -dependent profile. The XRR derived from the GIXOS-measured diffuse scattering, referred to in this paper as pseudo-reflectivity, provides a larger Qz range compared with the reflectivity measured by conventional reflectometry. Transforming the GIXOS-measured diffuse scattering profile to pseudo-XRR opens up the GIXOS method to widely available specular XRR analysis software tools. Here the GIXOS-derived pseudo-XRR is compared with the XRR measured by specular reflectometry from two simple vapor-liquid interfaces at different surface tension, and from a hexadecyltri-methyl-ammonium bromide monolayer on a water surface. For the simple liquids, excellent agreement (beyond 11 orders of magnitude in signal) is found between the two methods, supporting the approach of using GIXOS-measured diffuse scattering to derive reflectivities. Pseudo-XRR obtained at different horizontal offset angles with respect to the plane of incidence yields indistinguishable results, and this supports the robustness of the GIXOS-XRR approach. The pseudo-XRR method can be extended to soft thin films on a liquid surface, and criteria are established for the applicability of the approach.
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Affiliation(s)
- Chen Shen
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Honghu Zhang
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Benjamin M. Ocko
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
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2
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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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3
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Peng H, Liu H, Voigtmann T. Nonmonotonic Dynamical Correlations beneath the Surface of Glass-Forming Liquids. PHYSICAL REVIEW LETTERS 2022; 129:215501. [PMID: 36461957 DOI: 10.1103/physrevlett.129.215501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 12/20/2021] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
Collective motion over increasing length scales is a signature of the vitrification process of liquids. We demonstrate how distinct static and dynamic length scales govern the dynamics of vitrifying films. In contrast to a monotonically growing static correlation length, the dynamical correlation length that measures the extent of surface-dynamics acceleration into the bulk displays a striking nonmonotonic temperature evolution that is robust also against changes in detailed interatomic interaction. This nonmonotonic change defines a crossover temperature T_{*} that is distinct from the critical temperature T_{c} of mode-coupling theory. We connect this nonmonotonic change to a morphological change of cooperative rearrangement regions of fast particles, and to the point where the decoupling of fast-particle motion from the bulk relaxation is most sensitive to fluctuations. We propose a rigorous definition of this new crossover temperature T_{*} within a recent extension of mode-coupling theory, the stochastic β-relaxation theory.
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Affiliation(s)
- Hailong Peng
- School of Materials Science and Engineering, Central South University, 932 South Lushan Rd, 410083 Changsha, China
| | - Huashan Liu
- School of Materials Science and Engineering, Central South University, 932 South Lushan Rd, 410083 Changsha, China
| | - Thomas Voigtmann
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
- Department of Physics, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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4
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Verma N, Chen L, Fu Q, Wu S, Hsiao BS. Ionic Liquid-Mediated Interfacial Polymerization for Fabrication of Reverse Osmosis Membranes. MEMBRANES 2022; 12:1081. [PMID: 36363636 PMCID: PMC9696625 DOI: 10.3390/membranes12111081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
This study revealed the effects of incorporating ionic liquid (IL) molecules: 1-ethyl, 1-butyl, and 1-octyl-3-methyl-imidazolium chlorides with different alkyl chain lengths, in interfacial polymerization (IP) on the structure and property (i.e., permeate-flux and salt rejection ratio) relationships of resulting RO membranes. The IL additive was added in the aqueous meta-phenylene diamine (MPD; 0.1% w/v) phase, which was subsequently reacted with trimesoyl chloride (TMC; 0.004% w/v) in the hexane phase to produce polyamide (PA) barrier layer. The structure of resulting free-standing PA thin films was characterized by grazing incidence wide-angle X-rays scattering (GIWAXS), which results were correlated with the performance of thin-film composite RO membranes having PA barrier layers prepared under the same IP conditions. Additionally, the membrane surface properties were characterized by zeta potential and water contact angle measurements. It was found that the membrane prepared by the longer chain IL molecule generally showed lower salt rejection ratio and higher permeation flux, possibly due to the inclusion of IL molecules in the PA scaffold. This hypothesis was supported by the GIWAXS results, where a self-assembled surfactant-like structure formed by IL with the longest aliphatic chain length was detected.
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Affiliation(s)
- Nisha Verma
- Correspondence: (N.V.); (B.S.H.); Tel.: +1-631-632-7793 (B.S.H.)
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5
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Karunaratne W, Zhao M, Castner EW, Margulis CJ. Vacuum Interfacial Structure and X-ray Reflectivity of Imidazolium-Based Ionic Liquids with Perfluorinated Anions from a Theory and Simulations Perspective. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:13936-13945. [PMID: 36017361 PMCID: PMC9394757 DOI: 10.1021/acs.jpcc.2c03311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/22/2022] [Indexed: 06/15/2023]
Abstract
We report studies of the vacuum interfacial structure of a series of 1-methyl-3-alkylimidazolium bis(perfluoroalkanesulfonyl)imide ionic liquids (ILs) and predict and explain their Fresnel-normalized X-ray reflectivity. To better interpret the results, we use a theory we recently developed dubbed "the peaks and antipeaks analysis of reflectivity" which splits the overall signal into that of different pair subcomponents. Whereas the overall reflectivity signal is not very informative, the peak and trough intensities for the pair subcomponents provide rich information for analysis. When species containing cationic alkyl or anionic fluoroalkyl tails are present at the interface, a tail layer is found next to a vacuum, and this tail layer can be composed of both alkyl and fluoroalkyl moieties. To maintain the positive-negative alternation of charged groups, alkyl and fluoroalkyl tails must necessarily be nearby and cannot segregate. Charged groups are found in the subsequent layer just below the interface and arranged to achieve lateral charge neutrality. In general, fluctuations at and away from the interface are based on polarity (i.e., heads and tails) and not on charge; when there are no significant alkyl or fluoroalkyl moieties in the IL, atomic density fluctuations away from the interface are small and appear to exist for the purpose of achieving lateral charge balance. For all the systems reported here, the persistence length of density fluctuations does not go beyond ∼7 nm.
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Affiliation(s)
| | - Man Zhao
- 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
| | - Claudio J. Margulis
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
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6
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Liu M, Liu H, Peng H. Orientational wetting and dynamical correlations toward glass transition on the surface of imidazolium-based ionic liquids. J Chem Phys 2022; 157:034701. [DOI: 10.1063/5.0099845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Surface induces many fascinating physical phenomena, such as dynamic acceleration, surface anchoring, and orientational wetting, and, thus, is of great interest to study. Here, we report classic molecular dynamics simulations on the free-standing surface of imidazolium-based ionic liquids (ILs) [C4mim][PF6] and [C10mim][PF6]. On [C10mim][PF6] surface, a significant orientational wetting is observed, with the wetting strength showing a diverging tendency. Depth of the wetting was captured from the density and orientational order profile by a static length, which remarkably increases below the temperature Tstat upon cooling down. The dynamical correlation length that measures the distance of surface-dynamics acceleration into the bulk was characterized via the spatial-dependent mobility. The translational correlation exhibits a similar drastic increment at Tstat, while the rotational correlation drastically increases at a lower temperature Trot. We connect these results to the dynamics in bulk liquids, by finding Tstat and Trot that correspond to the onset temperatures where the liquids become cooperative for translational and rotational relaxation, respectively. This signifies the importance of collective dynamics in the bulk on the orientational wetting and surface dynamics in the ILs.
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Affiliation(s)
- Min Liu
- School of Materials Science and Engineering, Central South University, 932 South Lushan Rd., 410083 Changsha, China
| | - Huashan Liu
- School of Materials Science and Engineering, Central South University, 932 South Lushan Rd., 410083 Changsha, China
| | - Hailong Peng
- School of Materials Science and Engineering, Central South University, 932 South Lushan Rd., 410083 Changsha, China
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7
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Pontoni D, DiMichiel M, Deutsch M. Binary mixtures of homologous room-temperature ionic liquids: Nanoscale structure evolution with alkyl lengths’ difference. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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8
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Bomhardt K, Schneider P, Glaser T, Dürr M. Surface Properties of Ionic Liquids: A Mass Spectrometric View Based on Soft Cluster-Induced Desorption. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:974-980. [PMID: 35579531 DOI: 10.1021/jasms.2c00038] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Desorption/ionization induced by neutral clusters (DINeC) in combination with mass spectrometry (MS) was used for the investigation of the molecular composition of the surface of ionic liquids (IL). Based on the surface sensitivity of DINeC-MS, accumulation of either cations or anions was discriminated on the surface of bulk IL depending on the molecular structure of the IL components. In particular, cations with long alkyl chains aggregate on the surface, but this tendency is more reduced the larger the respective anion is; in the case of larger anions and smaller cations, it can be even reversed. For thin layers of IL, the ratio between cations and anions as detected in the mass spectra was found to be further influenced by the substrate surface.
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Affiliation(s)
- Karolin Bomhardt
- Institut für Angewandte Physik and Zentrum für Materialforschung, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Pascal Schneider
- Institut für Angewandte Physik and Zentrum für Materialforschung, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Timo Glaser
- Institut für Angewandte Physik and Zentrum für Materialforschung, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Michael Dürr
- Institut für Angewandte Physik and Zentrum für Materialforschung, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
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9
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Zhang S, Baba H, Sakka T, Nishi N. Interfacial Viscosity and Ionic Reorientation Probed Using Electrochemical Surface Plasmon Resonance at the Gold Electrode Interface of Ionic Liquids. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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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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11
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Winter L, Bhuin RG, Maier F, Steinrück HP. n-Butane, iso-Butane and 1-Butene Adsorption on Imidazolium-Based Ionic Liquids Studied with Molecular Beam Techniques. Chemistry 2021; 27:17059-17065. [PMID: 34499375 PMCID: PMC9293359 DOI: 10.1002/chem.202102492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Indexed: 11/11/2022]
Abstract
The interaction of molecules, especially hydrocarbons, at the gas/ionic liquid (IL) surface plays a crucial role in supported IL catalysis. The dynamics of this process is investigated by measuring the trapping probabilities of n‐butane, iso‐butane and 1‐butene on a set of frozen 1‐alkyl‐3‐methylimidazolium‐based ILs [CnC1Im]X, where n=4, 8 and X−=Cl−, Br−, [PF6]− and [Tf2N]−. The decrease of the initial trapping probability with increasing surface temperature is used to determine the desorption energy of the hydrocarbons at the IL surfaces. It increases with increasing alkyl chain length n and decreasing anion size for the ILs studied. We attribute these effects to different degrees of alkyl chain surface enrichment, while interactions between the adsorbate and the anion do not play a significant role. The adsorption energy also depends on the adsorbing molecule: It decreases in the order n‐butane>1‐butene>iso‐butane, which can be explained by different dispersion interactions.
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Affiliation(s)
- Leonhard Winter
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Radha G Bhuin
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Florian Maier
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Hans-Peter Steinrück
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
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12
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Nishi N, Uchiyashiki J, Oda T, Hino M, Yamada NL. Overscreening Induced by Ionic Adsorption at the Ionic Liquid/Electrode Interface Detected Using Neutron Reflectometry with a Rational Material Design. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20210328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Naoya Nishi
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510
| | - Junya Uchiyashiki
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510
| | - Tatsuro Oda
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581
| | - Masahiro Hino
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Kumatori, Osaka 590-0494
| | - Norifumi L. Yamada
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801
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13
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Wang YL, Li B, Laaksonen A. Coarse-grained simulations of ionic liquid materials: from monomeric ionic liquids to ionic liquid crystals and polymeric ionic liquids. Phys Chem Chem Phys 2021; 23:19435-19456. [PMID: 34524303 DOI: 10.1039/d1cp02662c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ionic liquid (IL) materials are promising electrolytes with striking physicochemical properties for energy and environmental applications. Heterogeneous structures and transport quantities of monomeric and polymeric ILs are intrinsically intercorrelated and span multiple spatiotemporal scales, which is more feasible for coarse-grained (CG) simulations than atomistic modelling. Herein we constructed a novel CG model for ethyl-imidazolium tetrafluoroborate ILs with varied cation alkyl chains ranging from C2 to C20, and the interaction parameters were validated against representative static and dynamic properties that were obtained from atomistic reference simulations and experimental characterizations at relevant thermodynamic states. This CG model was extended to study thermotropic phase behaviors of monomeric ILs and to explore ion association structures and ion transport quantities in polymeric ILs with different architectures. A systematic analysis of structural and dynamical quantities identifies an evolution of liquid morphology from homogeneous to nanosegregated structures and then a smectic mesomorphism via a gradual lengthening of cation alkyl chains, and thereafter a distinct structural transition characterized by a monotonic decrease in orientational and translational order parameters in a sequential heating cascade. Backbone and pendant polymeric ILs exhibit evident anion association structures with cation monomers and polymer chains, and striking intra- and interchain coordinations between cation monomers owing to an intrinsic polymer architecture effect. Such a peculiar ion pairing association leads to a progressive increase in anion intrachain hopping probabilities, and a concomitant decrease in anion interchain hopping events with a gradual lengthening of polymeric ILs. The anion diffusivities in polymeric ILs are intrinsically correlated with ion pairing association lifetimes and ion structural relaxation times via a universal power law correlation D ∼ τ-1, irrespective of polymer architectures.
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Affiliation(s)
- Yong-Lei Wang
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
| | - Bin Li
- School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China
| | - Aatto Laaksonen
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 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
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14
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Pontoni D, DiMichiel M, Deutsch M. Binary mixtures of homologous room-temperature ionic liquids: Temperature and composition evolution of the nanoscale structure. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116587] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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The dielectric response of phenothiazine-based glass-formers with different molecular complexity. Sci Rep 2021; 11:15816. [PMID: 34349137 PMCID: PMC8338989 DOI: 10.1038/s41598-021-95127-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
We examined a series of structurally related glass-forming liquids in which a phenothiazine-based tricyclic core (PTZ) was modified by attaching n-alkyl chains of different lengths (n = 4, 8, 10). We systematically disentangled the impact of chemical structure modification on the intermolecular organization and molecular dynamics probed by broadband dielectric spectroscopy (BDS). X-ray diffraction (XRD) patterns evidenced that all PTZ-derivatives are not 'ordinary' liquids and form nanoscale clusters. The chain length has a decisive impact on properties, exerting a plasticizing effect on the dynamics. Its elongation decreases glass transition temperature with slight impact on fragility. The increase in the medium-range order was manifested as a broadening of the dielectric loss peak reflected in the lower value of stretching parameter βKWW. A disagreement with the behavior observed for non-associating liquids was found as a deviation from the anti-correlation between the value of βKWW and the relaxation strength of the α-process. Besides, to explain the broadening of loss peak in PTZ with the longest (decyl) chain a slow Debye process was postulated. In contrast, the sample with the shortest alkyl chain and a less complex structure with predominant supramolecular assembly through π-π stacking exhibits no clear Debye-mode fingerprints. The possible reasons are also discussed.
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Iwahashi T, Ishiyama T, Sakai Y, Morita A, Kim D, Ouchi Y. Reply to the 'Comment on "Bi-layering at ionic liquid surfaces: a sum-frequency generation vibrational spectroscopy- and molecular dynamics simulation-based study"' by M. Deutsch, O. M. Magnussen, J. Haddad, D. Pontoni, B. M. Murphy and B. M. Ocko, Phys. Chem. Chem. Phys., 2021, DOI. Phys Chem Chem Phys 2021; 23:5028-5030. [PMID: 33595576 DOI: 10.1039/d1cp00171j] [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
In our recent paper titled "Bi-layering at ionic liquid surfaces: a sum-frequency generation vibrational spectroscopy- and molecular dynamics simulation-based study" co-authored by T. Iwahashi, T. Ishiyama, Y. Sakai, A. Morita, D. Kim, and Y. Ouchi, Phys. Chem. Chem. Phys., 2020, 22, 12565 (hereafter referred to as IW), the sum-frequency (SF) spectra for a homologous series of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([Cnmim][TFSA] n = 4, 6, 8, 10, and 12) were reported. In particular, a clear decrease in the SF signals from the [TFSA]- anions with increasing chain length of the [Cnmim]+ cation (Fig. 5 of IW) was explained in terms of "head-to-head" bi-layer formation at the air/ionic liquid (IL) interface. A comment by M. Deutsch et al. (hereafter referred to as DE) questioned this report, claiming that our proposed structure is not consistent with a multilayered electron density (ED) profile obtained by X-ray reflectivity (XR).
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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, 121-742, 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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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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18
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Pardon A, Bonhomme O, Gaillard C, Brevet PF, Benichou E. Nonlinear optical signature of nanostructural transition in ionic liquids. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114976] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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19
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Nishi N, Yamazawa T, Sakka T, Hotta H, Ikeno T, Hanaoka K, Takahashi H. How Viscous Is the Solidlike Structure at the Interface of Ionic Liquids? A Study Using Total Internal Reflection Fluorescence Spectroscopy with a Fluorescent Molecular Probe Sensitive to High Viscosity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:10397-10403. [PMID: 32787009 DOI: 10.1021/acs.langmuir.0c01528] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Aiming at the evaluation of the viscosity of the interfacial solidlike structure of ionic liquids (ILs), we performed total internal reflection fluorescence (TIRF) spectroscopy for N,N-diethyl-N'-phenyl-rhodamine (Ph-DER), a fluorescent probe that is sensitive to viscosity in a high-viscosity range. TIRF spectra at the glass interface of trioctylmethylammonium bis(nonafluorobutanesulfonyl)amide (TOMAC4C4N), a hydrophobic IL, showed that the fluorescence intensity of Ph-DER increases with the decrease of the evanescence penetration depth, suggesting that there exists a high-viscosity region at the interface. In contrast, glycerol, which is a molecular liquid with a bulk viscosity similar to that of TOMAC4C4N, did not show such a fluorescence increase, supporting that the formation of a highly viscous solidlike structure at the interface is intrinsic to ILs. A model analysis suggested that the high viscous region at the glass interface of TOMAC4C4N is at least twice thicker than the ionic multilayers at the air interface, implying that the solid substrate enhances the ordering of the interfacial structure of ILs. The viscosity at the glass interface of TOMAC4C4N was found to be at least 40 times higher than that of the liquid bulk.
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Affiliation(s)
- Naoya Nishi
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyotodaigakukatsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Takashi Yamazawa
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyotodaigakukatsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Tetsuo Sakka
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyotodaigakukatsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Hiroki Hotta
- Graduate School of Maritime Sciences, Kobe University, 5-1-1 Fukaeminami-machi, Higashinada-ku, Kobe 658-0022, Japan
| | - Takayuki Ikeno
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kenjiro Hanaoka
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiromi Takahashi
- System Instruments Co., Ltd, 776-2, Komiya-machi, Hachioji 192-0031, Tokyo, Japan
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20
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Pontoni D, DiMichiel M, Deutsch M. Nanoscale Structure in Short‐Chain Ionic Liquids. Chemphyschem 2020; 21:1887-1897. [DOI: 10.1002/cphc.202000548] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Indexed: 02/03/2023]
Affiliation(s)
- Diego Pontoni
- Partnership for Soft Condensed Matter (PSCM) ESRF – The European Synchrotron 71 Avenue des Martyrs 38043 Grenoble France
| | - Marco DiMichiel
- 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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21
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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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22
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Costa R, Pereira CM, Silva AF, Brevet PF, Benichou E. Ordering and Nonideality of Air-Ionic Liquid Interfaces in Surface Second Harmonic Generation. J Phys Chem B 2020; 124:3954-3961. [PMID: 32324418 DOI: 10.1021/acs.jpcb.9b12025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The air-ionic liquid interface for a series of ionic liquids involving imidazolium cations [Cnmim] with different alkyl chain lengths (n = 2, 4, 6, 8, 10, and 12) and the same [NTf2] imide anion has been studied by polarization-resolved second harmonic generation (SHG). An increase as a function of the alkyl chain length of the orientational parameter reveals the increasing ordering of the air-pure ionic liquid interfaces although it is not possible to disentangle the change in mean tilt angle from a change in the tilt angle probability distribution width. Besides, the study of the air-mixed ([C12mim])x([C2mim])1-x[NTf2] ionic liquid interface clearly demonstrates the interfacial nonideality of the mixed ionic liquids. The long alkyl chain cation perturbs the interface as seen from the orientational parameter and displaces the short alkyl chain one for bulk mixture contents as low as 10%. At higher long alkyl chain cation bulk mixture contents, the interface behaves close to a pure long alkyl chain ionic liquid.
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Affiliation(s)
- Renata Costa
- Departamento de Quı̀mica e Bioquı̀mica, CIQUP-Physical Analytical Chemistry and Electrochemistry Group, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - Carlos M Pereira
- Departamento de Quı̀mica e Bioquı̀mica, CIQUP-Physical Analytical Chemistry and Electrochemistry Group, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - A Fernando Silva
- Departamento de Quı̀mica e Bioquı̀mica, CIQUP-Physical Analytical Chemistry and Electrochemistry Group, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - Pierre-François Brevet
- Université de Lyon, Université Claude Bernard Lyon, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
| | - Emmanuel Benichou
- Université de Lyon, Université Claude Bernard Lyon, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
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23
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Wang Y, Jarošová R, Swain GM, Blanchard GJ. Characterizing the Magnitude and Structure-Dependence of Free Charge Density Gradients in Room-Temperature Ionic Liquids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:3038-3045. [PMID: 32148037 DOI: 10.1021/acs.langmuir.0c00237] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We have reported previously on the existence of charge-induced long-range organization in the room-temperature ionic liquid (RTIL), BMIM+BF4-. The induced organization is in the form of a free charge density gradient (ρf) that exists over ca. 100 μm into the RTIL in contact with a charged surface. The fluorescence anisotropy decay of a trace-level charged chromophore in the RTIL is measured as a function of distance from the indium-doped tin oxide support surface to probe this free charge density gradient. We report here on the characterization of the free charge density gradient in five different imidazolium RTILs and use these data to evaluate the magnitude of the induced free charge density gradient. Both the extent and magnitude of this gradient depend on the chemical structures of the cationic and anionic constituents of the RTIL used. Control over the magnitude of ρf has implications for the utility of RTILs for a host of applications that remain to be explored fully.
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Affiliation(s)
- Yufeng Wang
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Romana Jarošová
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
- Faculty of Science, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic
| | - Greg M Swain
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Gary J Blanchard
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
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24
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Narayanan T, Konovalov O. Synchrotron Scattering Methods for Nanomaterials and Soft Matter Research. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E752. [PMID: 32041363 PMCID: PMC7040635 DOI: 10.3390/ma13030752] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 12/17/2022]
Abstract
This article aims to provide an overview of broad range of applications of synchrotron scattering methods in the investigation of nanoscale materials. These scattering techniques allow the elucidation of the structure and dynamics of nanomaterials from sub-nm to micron size scales and down to sub-millisecond time ranges both in bulk and at interfaces. A major advantage of scattering methods is that they provide the ensemble averaged information under in situ and operando conditions. As a result, they are complementary to various imaging techniques which reveal more local information. Scattering methods are particularly suitable for probing buried structures that are difficult to image. Although, many qualitative features can be directly extracted from scattering data, derivation of detailed structural and dynamical information requires quantitative modeling. The fourth-generation synchrotron sources open new possibilities for investigating these complex systems by exploiting the enhanced brightness and coherence properties of X-rays.
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25
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Pontoni D, DiMichiel M, Deutsch M. Temperature evolution of the bulk nano-structure in a homologous series of room temperature ionic liquids. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.112280] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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26
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Weiss H, Cheng HW, Mars J, Li H, Merola C, Renner FU, Honkimäki V, Valtiner M, Mezger M. Structure and Dynamics of Confined Liquids: Challenges and Perspectives for the X-ray Surface Forces Apparatus. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:16679-16692. [PMID: 31614087 PMCID: PMC6933819 DOI: 10.1021/acs.langmuir.9b01215] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 10/15/2019] [Indexed: 05/21/2023]
Abstract
The molecular-scale structure and dynamics of confined liquids has increasingly gained relevance for applications in nanotechnology. Thus, a detailed knowledge of the structure of confined liquids on molecular length scales is of great interest for fundamental and applied sciences. To study confined structures under dynamic conditions, we constructed an in situ X-ray surface forces apparatus (X-SFA). This novel device can create a precisely controlled slit-pore confinement down to dimensions on the 10 nm scale by using a cylinder-on-flat geometry for the first time. Complementary structural information can be obtained by simultaneous force measurements and X-ray scattering experiments. The in-plane structure of liquids parallel to the slit pore and density profiles perpendicular to the confining interfaces are studied by X-ray scattering and reflectivity. The normal load between the opposing interfaces can be modulated to study the structural dynamics of confined liquids. The confinement gap distance is tracked simultaneously with nanometer precision by analyzing optical interference fringes of equal chromatic order. Relaxation processes can be studied by driving the system out of equilibrium by shear stress or compression/decompression cycles of the slit pore. The capability of the new device is demonstrated on the liquid crystal 4'-octyl-4-cyano-biphenyl (8CB) in its smectic A (SmA) mesophase. Its molecular-scale structure and orientation confined in 100 nm to 1.7 μm slit pores was studied under static and dynamic nonequilibrium conditions.
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Affiliation(s)
- Henning Weiss
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Hsiu-Wei Cheng
- Institute
of Applied Physics, Vienna Institute of
Technology, Wiedner Hauptstrasse 8-10/E134, 1040 Wien, Austria
| | - Julian Mars
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Institute
of Physics, Johannes Gutenberg University
Mainz, 55128 Mainz, Germany
| | - Hailong Li
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Claudia Merola
- Institute
of Applied Physics, Vienna Institute of
Technology, Wiedner Hauptstrasse 8-10/E134, 1040 Wien, Austria
| | - Frank Uwe Renner
- Institute
for Materials Research, Hasselt University, 3590 Diepenbeek, Belgium
| | - Veijo Honkimäki
- ESRF-European
Synchrotron Radiation Facility, Avenue des Martyrs 71, 38043 Grenoble, Cedex 9, France
| | - Markus Valtiner
- Institute
of Applied Physics, Vienna Institute of
Technology, Wiedner Hauptstrasse 8-10/E134, 1040 Wien, Austria
- Max-Planck-Institut
für Eisenforschung GmbH, Max-Planck-Strasse 1, 40237 Düsseldorf, Germany
| | - Markus Mezger
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Institute
of Physics, Johannes Gutenberg University
Mainz, 55128 Mainz, Germany
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27
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Liber SR, Butenko AV, Caspi M, Guttman S, Schultz M, Schofield AB, Deutsch M, Sloutskin E. Precise Self-Positioning of Colloidal Particles on Liquid Emulsion Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13053-13061. [PMID: 31502850 DOI: 10.1021/acs.langmuir.9b01833] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Decorating emulsion droplets by particles stabilizes foodstuff and pharmaceuticals. Interfacial particles also influence aerosol formation, thus impacting atmospheric CO2 exchange. While studies of particles at disordered droplet interfaces abound in the literature, such studies for ubiquitous ordered interfaces are not available. Here, we report such an experimental study, showing that particles residing at crystalline interfaces of liquid droplets spontaneously self-position to specific surface locations, identified as structural topological defects in the crystalline surface monolayer. This monolayer forms at temperature T = Ts, leaving the droplet liquid and driving at Td < Ts a spontaneous shape-change transition of the droplet from spherical to icosahedral. The particle's surface position remains unchanged in the transition, demonstrating these positions to coincide with the vertices of the sphere-inscribed icosahedron. Upon further cooling, droplet shape-changes to other polyhedra occur, with the particles remaining invariably at the polyhedra's vertices. At still lower temperatures, the particles are spontaneously expelled from the droplets. Our results probe the molecular-scale elasticity of quasi-two-dimensional curved crystals, impacting also other fields, such as protein positioning on cell membranes, controlling essential biological functions. Using ligand-decorated particles, and the precise temperature-tunable surface position control found here, may also allow using these droplets for directed supra-droplet self-assembly into larger structures, with a possible post-assembly structure fixation by UV polymerization of the droplet's liquid.
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Affiliation(s)
- Shir R Liber
- Physics Department and Institute of Nanotechnology & Advanced Materials , Bar-Ilan University , Ramat-Gan 5290002 , Israel
| | - Alexander V Butenko
- Physics Department and Institute of Nanotechnology & Advanced Materials , Bar-Ilan University , Ramat-Gan 5290002 , Israel
| | - Moshe Caspi
- Physics Department and Institute of Nanotechnology & Advanced Materials , Bar-Ilan University , Ramat-Gan 5290002 , Israel
| | - Shani Guttman
- Physics Department and Institute of Nanotechnology & Advanced Materials , Bar-Ilan University , Ramat-Gan 5290002 , Israel
| | - Moty Schultz
- Physics Department and Institute of Nanotechnology & Advanced Materials , Bar-Ilan University , Ramat-Gan 5290002 , Israel
| | - Andrew B Schofield
- The School of Physics and Astronomy , University of Edinburgh , Edinburgh EH9 3FD , U.K
| | - Moshe Deutsch
- Physics Department and Institute of Nanotechnology & Advanced Materials , Bar-Ilan University , Ramat-Gan 5290002 , Israel
| | - Eli Sloutskin
- Physics Department and Institute of Nanotechnology & Advanced Materials , Bar-Ilan University , Ramat-Gan 5290002 , Israel
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28
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Vučemilović-Alagić N, Banhatti RD, Stepić R, Wick CR, Berger D, Gaimann MU, Baer A, Harting J, Smith DM, Smith AS. Insights from molecular dynamics simulations on structural organization and diffusive dynamics of an ionic liquid at solid and vacuum interfaces. J Colloid Interface Sci 2019; 553:350-363. [DOI: 10.1016/j.jcis.2019.06.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 10/26/2022]
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29
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Esperança JMSS, Tariq M, Pereiro AB, Araújo JMM, Seddon KR, Rebelo LPN. Anomalous and Not-So-Common Behavior in Common Ionic Liquids and Ionic Liquid-Containing Systems. Front Chem 2019; 7:450. [PMID: 31281812 PMCID: PMC6596442 DOI: 10.3389/fchem.2019.00450] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 06/05/2019] [Indexed: 11/27/2022] Open
Abstract
This work highlights unexpected, not so well known responses of ionic liquids and ionic liquid-containing systems, which are reported in a collective manner, as a short review. Examples include: (i) Minima in the temperature dependence of the isobaric thermal expansion coefficient of some ILs; (ii) Viscosity Minima in binary mixtures of IL + Molecular solvents; (iii) Anomalies in the surface tension within a family of ILs; (iv) The constancy among IL substitution of Cp/Vm at and around room temperature; (v) ILs as glass forming liquids; (vi) Alternate odd-even side alkyl chain length effects; (vii) Absolute negative pressures in ILs and IL-containing systems; (viii) Reversed-charged ionic liquid pairs; (ix) LCST immiscibility behavior in IL + solvent systems.
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Affiliation(s)
- José M S S Esperança
- LAQV/REQUIMTE, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Caparica, Portugal
| | - Mohammad Tariq
- LAQV/REQUIMTE, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Caparica, Portugal
| | - Ana B Pereiro
- LAQV/REQUIMTE, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Caparica, Portugal
| | - João M M Araújo
- LAQV/REQUIMTE, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Caparica, Portugal
| | - Kenneth R Seddon
- QUILL Research Centre, the Queen's University of Belfast, Belfast, United Kingdom
| | - Luis Paulo N Rebelo
- LAQV/REQUIMTE, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Caparica, Portugal
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30
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Rauber D, Philippi F, Zapp J, Kickelbick G, Natter H, Hempelmann R. Transport properties of protic and aprotic guanidinium ionic liquids. RSC Adv 2018; 8:41639-41650. [PMID: 35559272 PMCID: PMC9091945 DOI: 10.1039/c8ra07412g] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/16/2018] [Indexed: 12/03/2022] Open
Abstract
Ionic liquids (ILs) are a promising class of solvents, functional fluids and electrolytes that are of high interest for both basic as well as applied research. For further fundamental understanding of ILs and a successful implementation in technical processes, a deeper insight into transport properties and their interrelations is of particular importance. In this contribution we synthesised a series of mostly novel protic and aprotic ILs based on the tetramethylguanidinium (TMG) cation that is a derivative of the superbase guanidine. Different substitution patterns and anions from acids with broadly varied pKa values were investigated. We measured general properties, such as thermal transitions and densities of these ILs, as well as their transport quantities by means of rheology, impedance spectroscopy and NMR diffusometry. Different models for the correlation of the transport properties, namely the Nernst–Einstein, Walden and Stokes–Einstein–Sutherland relations were applied. The deviation from ideal behaviour of fully dissociated electrolytes, often termed as ionicity, was quantified by the reciprocal Haven ratio, fractional Walden rule and ionicity obtained from the Walden plot. Velocity cross-correlation coefficients were calculated to gain further insight into the correlation between ion movements. Both protic and aprotic TMG ILs show transport properties comparable to other ILs with similar molecular weight and high ionicity values especially in contrast to other protic ILs. Lowest ionicity values were found for the protic ILs with smallest ΔpKa values between constituting acid and base. This can either be explained by stronger hydrogen bonding between cation and anion or lower anti-correlations between the oppositely charged ions. These results aim to provide insight into the properties of this interesting cations class and a deeper understanding of the transport properties of ILs and their interrelations in general. New protic and aprotic ionic liquids based on superbase cations show promising properties and enrich the field of cation classes![]()
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Affiliation(s)
- Daniel Rauber
- Physical Chemistry
- Saarland University
- 66123 Saarbrücken
- Germany
- Transfercenter Sustainable Electrochemistry
| | | | - Josef Zapp
- Pharmaceutical Biology
- Saarland University
- 66123 Saarbrücken
- Germany
| | - Guido Kickelbick
- Inorganic Solid State Chemistry
- Saarland University
- 66123 Saarbrücken
- Germany
| | - Harald Natter
- Physical Chemistry
- Saarland University
- 66123 Saarbrücken
- Germany
- Transfercenter Sustainable Electrochemistry
| | - Rolf Hempelmann
- Physical Chemistry
- Saarland University
- 66123 Saarbrücken
- Germany
- Transfercenter Sustainable Electrochemistry
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