1
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Srinivasan H, Sharma VK, Mitra S. Modulation of Diffusion Mechanism and Its Correlation with Complexation in Aqueous Deep Eutectic Solvents. J Phys Chem B 2022; 126:9026-9037. [PMID: 36315464 DOI: 10.1021/acs.jpcb.2c05312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Aqueous mixtures of deep eutectic solvents (DESs) have gained traction recently as an effective template to tailor their physicochemical properties. But detailed microscopic insights into the effects of water on the molecular relaxation phenomenon in DESs are not entirely understood. DESs are strong network-forming liquids due to the extensive hydrogen bonding and complex formation between their species, and therefore, water can behave as a controlled disruptor altering the microscopic structure and dynamics in DESs. In this study, the role of water in the diffusion mechanism of acetamide in the aqueous mixtures of DESs synthesized using acetamide and lithium perchlorate is investigated using molecular dynamics (MD) simulation and quasielastic neutron scattering (QENS). The acetamide dynamics comprises localized diffusion within transient cages and a jump diffusion process across cages. The jump diffusion process is observed to be strongly enhanced by about a factor of 10 as the water content in the system is increased. Meanwhile, the geometry of the localized dynamics is unaltered by addition of water, but the localized diffusion becomes significantly faster and more heterogeneous with increasing water concentration. The accelerating effects of water on localized diffusion are also substantiated by QENS experiments. The water concentration in the DES is observed to control the solvation structure of lithium ions, with the ions becoming significantly hydrated at 20 wt % water. The formation of interwater and water-acetamide hydrogen bonds is observed. The increase in water concentration is found to increase the number of H-bonds; however, their lifetimes are found to decrease substantially. Similarly, the lifetimes of acetamide-lithium complexes are also found to be diminished by increasing water concentration. A power-law scaling relationship between lifetimes and diffusion constants is established, elucidating the extent of coupling between diffusive processes and hydrogen bonding and microscopic complexation. This study demonstrates the ability to use water as an agent to probe the role of structural relaxation and complex lifetimes of diffusive processes at different time and length scales.
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Affiliation(s)
- H Srinivasan
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai400085, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai400094, India
| | - V K Sharma
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai400085, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai400094, India
| | - S Mitra
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai400085, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai400094, India
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2
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Ostadsharif Memar Z, Moosavi M. A combined QTAIM, DFT and molecular dynamics study on the nanoscale dynamical and structural organization of imidazolium-based dicationic ionic liquids. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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3
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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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4
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Liu S, Li R, Tyagi M, Akcora P. Confinement Effects in Dynamics of Ionic Liquids with Polymer-Grafted Nanoparticles. Chemphyschem 2022; 23:e202200219. [PMID: 35676199 DOI: 10.1002/cphc.202200219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/07/2022] [Indexed: 11/07/2022]
Abstract
Ionic liquid mixed with poly(methyl methacrylate)-grafted nanoparticle aggregates at low particle concentrations was shown to exhibit different dynamics and ionic conductivity than that of pure ionic liquid in our previous studies. In this work, we report on the quasi-elastic neutron scattering results on ionic liquid containing polymer-grafted nanoparticles at the higher particle concentration. The diffusivity of imidazolium (HMIM + ) cations of 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIM-TFSI) in the presence of poly(methyl methacrylate)-grafted iron oxide nanoparticles and the ionic conductivity of solutions were discussed through the confinement. Analysis of the elastic incoherent structure factor suggested the confinement radius decreased with the addition of grafted particles in HMIM-TFSI/solvent mixture, indicating the confinement that is induced by the high concentration of grafted particles, shrinks the HMIM-TFSI restricted volume. We further conjecture that this enhanced diffusivity occurs as a result of the local ordering of cations within aggregates of poly(methyl methacrylate)-grafted particles.
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Affiliation(s)
- Siqi Liu
- 1 Castle Point on Hudson, Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, McLean Hall 415, 07030, Hoboken, NJ, USA
| | - Ruhao Li
- 1 Castle Point on Hudson, Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, McLean Hall 415, 07030, Hoboken, NJ, USA
| | - Madhusudan Tyagi
- NIST Center for Neutron Research, 100 Bureau Dr, 20899, Gaithersburg, MD, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, 20742, Maryland, MD, USA
| | - Pinar Akcora
- 1 Castle Point on Hudson, Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, McLean Hall 415, 07030, Hoboken, NJ, USA
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5
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Barik S, Chakraborty M, Mahapatra A, Sarkar M. Choline chloride and ethylene glycol based deep eutectic solvent (DES) versus hydroxyl functionalized room temperature ionic liquids (RTILs): assessing the differences in microscopic behaviour between the DES and RTILs. Phys Chem Chem Phys 2022; 24:7093-7106. [PMID: 35262105 DOI: 10.1039/d1cp05010a] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
With the aim of understanding the differences in the behavior of deep eutectic solvents (DESs) and room temperature ionic liquids (RTILs) in terms of their structure, dynamics, and intra- and intermolecular interactions, three different ILs and one DES having similar functionalities (hydroxyl) have been investigated by using both ensembled average and single-molecule spectroscopic techniques. Specifically, for this purpose, a choline chloride based DES (ethaline) and three hydroxyl functionalized ILs (1-(2-hydroxyethyl)-3-imidazolium bis(trifluoromethanesulfonyl)imide ([OHEMIM][NTF2]), N-(2-hydroxyl ethyl)-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([OHEMPy][NTf2]), and N-(2-hydroxyethyl)-N,N-dimethylpropan-1-aminium bis(trifluoromethanesulfonyl)imide ([OHC3CH][NTf2])) are employed and investigated by EPR, time-resolved fluorescence, NMR and FCS studies. Estimation of polarity through EPR spectroscopy has revealed that the hydroxyl ILs employed in these studies are hyper-polar (close to water) in nature, whereas the polarity of the DES is found to be close to those of aliphatic polyhydroxy-alcohols. Interestingly, both time-resolved fluorescence anisotropy and FCS studies on these systems have suggested that the hydroxyl ILs are more dynamically heterogeneous than the DES. More interestingly, PFG-NMR measurements have indicated that the fluid structure of ethaline is relatively more associated as compared to those of the ILs despite the fact that all the cations have the same hydroxyl functionalities. All these investigations have essentially demonstrated that, despite having similar functionalities, both the DES and hydroxyl ILs employed in the present study exhibit microscopic behaviours that are significantly different from each other, indicating the interplay of various intermolecular interactions within the constituent species in governing the behaviours of these solvent systems.
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Affiliation(s)
- Sahadev Barik
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Jatni, Khurda, Bhubaneswar, 752050, Odisha, India. .,Centre of Interdisciplinary Science (CIS), NISER, Bhubaneswar, Jatni, Khurda, 752050, Odisha, India
| | - Manjari Chakraborty
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Jatni, Khurda, Bhubaneswar, 752050, Odisha, India. .,Centre of Interdisciplinary Science (CIS), NISER, Bhubaneswar, Jatni, Khurda, 752050, Odisha, India
| | - Amita Mahapatra
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Jatni, Khurda, Bhubaneswar, 752050, Odisha, India. .,Centre of Interdisciplinary Science (CIS), NISER, Bhubaneswar, Jatni, Khurda, 752050, Odisha, India
| | - Moloy Sarkar
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Jatni, Khurda, Bhubaneswar, 752050, Odisha, India. .,Centre of Interdisciplinary Science (CIS), NISER, Bhubaneswar, Jatni, Khurda, 752050, Odisha, India
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6
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Ivanov MY, Prikhod’ko SA, Bakulina OD, Kiryutin AS, Adonin NY, Fedin MV. Validation of Structural Grounds for Anomalous Molecular Mobility in Ionic Liquid Glasses. Molecules 2021; 26:5828. [PMID: 34641371 PMCID: PMC8510339 DOI: 10.3390/molecules26195828] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 11/25/2022] Open
Abstract
Ionic liquid (IL) glasses have recently drawn much interest as unusual media with unique physicochemical properties. In particular, anomalous suppression of molecular mobility in imidazolium IL glasses vs. increasing temperature was evidenced by pulse Electron Paramagnetic Resonance (EPR) spectroscopy. Although such behavior has been proven to originate from dynamics of alkyl chains of IL cations, the role of electron spin relaxation induced by surrounding protons still remains unclear. In this work we synthesized two deuterated imidazolium-based ILs to reduce electron-nuclear couplings between radical probe and alkyl chains of IL, and investigated molecular mobility in these glasses. The obtained trends were found closely similar for deuterated and protonated analogs, thus excluding the relaxation-induced artifacts and reliably demonstrating structural grounds of the observed anomalies in heterogeneous IL glasses.
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Affiliation(s)
- Mikhail Yu. Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
| | - Sergey A. Prikhod’ko
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia; (S.A.P.); (N.Y.A.)
| | - Olga D. Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
| | - Alexey S. Kiryutin
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
| | - Nicolay Yu. Adonin
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia; (S.A.P.); (N.Y.A.)
| | - Matvey V. Fedin
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
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7
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Hodge SR, Corcelli SA, Berg MA. Nonlinear measurements of kinetics and generalized dynamical modes. II. Application to a simulation of solvation dynamics in an ionic liquid. J Chem Phys 2021; 155:024123. [PMID: 34266263 DOI: 10.1063/5.0053424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Solvation dynamics in ionic liquids show features that are often associated with supercooled liquids, including "stretched" nonexponential relaxation. To better understand the mechanism behind the stretching, the nonlinear mode-correlation methods proposed in Paper I [S. R. Hodge and M. A. Berg, J. Chem. Phys. 155, 024122 (2021)] are applied to a simulation of a prototypical ionic liquid. A full Green's function is recovered. In addition, specific tests for non-Gaussian dynamics are made. No deviations from Gaussian dynamics are found. This finding is incompatible with rate heterogeneity as a cause of the nonexponential relaxation and appears to be in conflict with an earlier multidimensional analysis of the same data. Although this conflict is not resolved here, this work does demonstrate the practicality of mode-correlation analysis in the face of finite datasets and calculations.
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Affiliation(s)
- Stuart R Hodge
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA
| | - Steven A Corcelli
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Mark A Berg
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA
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8
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Cruz C, Ciach A. Phase Transitions and Electrochemical Properties of Ionic Liquids and Ionic Liquid-Solvent Mixtures. Molecules 2021; 26:3668. [PMID: 34208542 PMCID: PMC8234089 DOI: 10.3390/molecules26123668] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/04/2021] [Accepted: 06/10/2021] [Indexed: 12/20/2022] Open
Abstract
Recent advances in studies of ionic liquids (IL) and ionic liquid-solvent mixtures are reviewed. Selected experimental, simulation, and theoretical results for electrochemical, thermodynamical, and structural properties of IL and IL-solvent mixtures are described. Special attention is paid to phenomena that are not predicted by the classical theories of the electrical double layer or disagree strongly with these theories. We focus on structural properties, especially on distribution of ions near electrodes, on electrical double layer capacitance, on effects of confinement, including decay length of a dissjoining pressure between confinig plates, and on demixing phase transition. In particular, effects of the demixing phase transition on electrochemical properties of ionic liquid-solvent mixtures for different degrees of confinement are presented.
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Affiliation(s)
| | - Alina Ciach
- Institute of Physical Chemistry, Polish Academy of Sciences, 44/52, 01-224 Warsaw, Poland;
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9
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Torkzadeh M, Moosavi M. Heterogeneity in microstructures and dynamics of dicationic ionic liquids with symmetric and asymmetric cations. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115632] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Torkzadeh M, Moosavi M. Probing the Effect of Side Alkyl Chain Length on the Structural and Dynamical Micro-heterogeneities in Dicationic Ionic Liquids. J Phys Chem B 2020; 124:11446-11462. [PMID: 33283503 DOI: 10.1021/acs.jpcb.0c07034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The molecular dynamics simulations and Voronoi tessellation analysis of two dicationic ionic liquids (DILs) including [C5(mim)2][NTf2]2 and [C5(mim)2C4][NTf2]2 have been carried out to investigate the effects of side alkyl chain length on the structural and dynamical micro-heterogeneity of these DILs. Radial distribution functions (RDFs), spatial distribution functions (SDFs), and also neighborhood analysis of ions have been calculated to determine the arrangement of the nearest neighboring ions. To better understand the hydrogen-bonding network, microstructures, inter- and intramolecular orientations of ions in the studied DILs, different kinds of combined distribution functions (CDFs) were computed and analyzed. Also, qualitative and quantitative analyses of the structural heterogeneity were explored through total/partial structure factors, heterogeneity order parameters (HOPs), and domain analysis from Voronoi tessellation. The results showed that the side alkyl chains in DILs have significant effects on their micro-organizations in such a way that [C5(mim)2C4][NTf2]2 with longer side chains has more microstructural heterogeneity than [C5(mim)2][NTf2]2 where the linkage alkyl chain is the same in both of them. Furthermore, to shed light on the dynamical heterogeneity, ion pair, ion cage, and hydrogen-bond stabilities and also the reorientation dynamics of ions have been investigated. Results demonstrated that local dynamics differences originate from local structural heterogeneity.
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Affiliation(s)
| | - Majid Moosavi
- Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran
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11
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Abstract
The extent to which cations and anions in ionic liquids (ILs) and ionic liquid solutions are dissociated is of both fundamental scientific interest and practical importance because ion dissociation has been shown to impact viscosity, density, surface tension, volatility, solubility, chemical reactivity, and many other important chemical and physical properties. When mixed with solvents, ionic liquids provide the unique opportunity to investigate ion dissociation from infinite dilution in the solvent to a completely solvent-free state, even at ambient conditions. The most common way to estimate ion dissociation in ILs and IL solutions is by comparing the molar conductivity determined from ionic conductivity measurements such as electrochemical impedance spectroscopy (EIS) (which measure the movement of only the charged, i.e., dissociated, ions) with the molar conductivity calculated from ion diffusivities measured by pulse field gradient nuclear magnetic resonance spectroscopy (PFG-NMR, which gives movement of all of the ions). Because the NMR measurements are time-consuming, the number of ILs and IL solutions investigated by this method is relatively limited. We have shown that use of the Stokes-Einstein equation with estimates of the effective ion Stokes radii allows ion dissociation to be calculated from easily measured density, viscosity, and ionic conductivity data (ρ, η, λ), which is readily available in the literature for a much larger number of pure ILs and IL solutions. Therefore, in this review, we present values of ion dissociation for ILs and IL solutions (aqueous and nonaqueous) determined by both the traditional molar conductivity/PFG-NMR method and the ρ, η, λ method. We explore the effect of cation and anion alkyl chain length, structure, and interaction motifs of the cation and anion, temperature, and the strength of the solvent in IL solutions.
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Affiliation(s)
- Oscar Nordness
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Joan F Brennecke
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
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12
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Photoinduced reactions between naphthoquinone and N,N,N′,N′-tetramethyl-p-phenylenediamine in the mixture of ionic liquid [BPy][NTf2] and acetonitrile studied by transient spectroscopy. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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13
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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: 197] [Impact Index Per Article: 49.3] [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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14
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Wang YL, Li B, Laaksonen A, Yuan J. The Effect of Phenyl Substitutions on Microstructures and Dynamics of Tetraalkylphosphonium Bis(trifluoro- methylsulfonyl)imide Ionic Liquids. Chemphyschem 2020; 21:1202-1214. [PMID: 32181955 DOI: 10.1002/cphc.201901206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 02/24/2020] [Indexed: 01/15/2023]
Abstract
Extensive atomistic simulations demonstrated that a gradual substitution of hexyl chains with phenyl groups in tetraalkylphosphonium cations results in remarkable changes in hydrogen bonding interactions, liquid structures and scattering structural functions, and rotational dynamics of hexyl chains and phenyl groups in tetraalkylphosphonium bis(trifluoromethylsulfonyl)imide ionic liquids. Hydrogen donor sites in hexyl chains present competitive characteristics with those in phenyl groups in coordinating anions, as well as their continuous and intermittent hydrogen bonding dynamics. Cation-cation and anion-anion spatial correlations show concomitant shift to short distances with decreased peak intensities with variations of cation structures, whereas cation-anion correlations have a distinct shift to large radial distances due to decreased associations of anions with neighboring cations. These microstructural changes are qualitatively manifested in shifts of prominent peaks for prevalent charge alternations and adjacency correlations between ion species in scattering structural functions. Meanwhile, rotational dynamics of hexyl chains speed up, which, in turn, slow down rotations of phenyl groups, whereas anions exhibit imperceptible changes in their rotational dynamics. These computational results are intrinsically correlated with conformational flexibilities, molecular sizes, and steric hindrance effects of phenyl groups in comparison with hexyl chains, and constrained distributions of anions around cations in heterogeneous ionic environments.
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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
| | - Aatto Laaksonen
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden.,Centre of Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry Aleea Grigore Ghica-Voda, 41A, 700487, Iasi, Romania
| | - Jiayin Yuan
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
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15
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Casalegno M, Castiglione F, Raos G, Appetecchi GB, Passerini S, Mele A, Ragg E. Magnetic Resonance Imaging and Molecular Dynamics Characterization of Ionic Liquid in Poly(ethylene oxide)-Based Polymer Electrolytes. ACS APPLIED MATERIALS & INTERFACES 2020; 12:23800-23811. [PMID: 32352774 PMCID: PMC8007074 DOI: 10.1021/acsami.0c01890] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
Ternary systems consisting of polymers, lithium salts, and ionic liquids (ILs) are promising materials for the development of next-generation lithium batteries. The ternary systems combine the advantages of polymer-salt and IL-salt systems, thus providing media with high ionic conductivity and solid-like mechanical properties. In this work, we apply nuclear magnetic resonance 1H microimaging [magnetic resonance imaging (MRI)] techniques and molecular dynamics (MD) simulations to study the translational and rotational dynamics of the N-butyl-N-methylpyrrolidinium (PYR14) cation in poly(ethylene oxide) (PEO) matrices containing the lithium bis(trifluoromethanesulfonyl) imide salt (LiTFSI) and the PYR14TFSI IL. The analysis of diffusion-weighted images in PEO/LiTFSI/PYR14TFSI samples with varying mole ratios (10:1:x, with x = 1, 2, 3, and 4) shows, in a wide range of temperatures, a spatially heterogeneous distribution of PYR14 diffusion coefficients. Their weight-averaged values increase with IL content but remain well below the values estimated for the neat IL. The analysis of T2 (spin-spin relaxation) parametric images shows that the PEO matrix significantly hinders PYR14 rotational freedom, which is only partially restored by increasing the IL content. The MD simulations, performed on IL-filled cavities within the PEO matrix, reveal that PYR14 diffusion is mainly affected by Li/TFSI coordination within the IL phase. In agreement with MRI experiments, increasing the IL content increases the PYR14 diffusion coefficients. Finally, the analysis of MD trajectories suggests that Li diffusion mostly develops within the IL phase, although a fraction of Li cations is strongly coordinated by PEO oxygen atoms.
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Affiliation(s)
- Mosè Casalegno
- Dipartimento
di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Politecnico di Milano, 20131 Milano, Italy
| | - Franca Castiglione
- Dipartimento
di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Politecnico di Milano, 20131 Milano, Italy
| | - Guido Raos
- Dipartimento
di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Politecnico di Milano, 20131 Milano, Italy
| | - Giovanni Battista Appetecchi
- Snergy
and Sustainable Economic Development, Materials and Physicochemical
Processes Technical Unit, ENEA, Italian
National Agency for New Technology, Via Anguillarese 301, 00196 Rome, Italy
| | - Stefano Passerini
- Helmholtz
Institute of Ulm (HIU), Strasse 11, 89081 Ulm, Germany
- Karlsruhe
Institute of Technology (KIT), P.O. Box
3640, 76021 Karlsruhe, Germany
| | - Andrea Mele
- Dipartimento
di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Politecnico di Milano, 20131 Milano, Italy
| | - Enzio Ragg
- Dipartimento
di Scienze Molecolari Agroalimentari, Università
di Milano, 20131 Milano, Italy
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16
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Pei HW, Li B, Laaksonen A, Wang YL. How Molecular Chiralities of Bis(mandelato)borate Anions Affect Their Binding Structures With Alkali Metal Ions and Microstructural Properties in Tetraalkylphosphonium Ionic Liquids. Front Chem 2020; 8:65. [PMID: 32117888 PMCID: PMC7028760 DOI: 10.3389/fchem.2020.00065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 01/20/2020] [Indexed: 11/13/2022] Open
Abstract
Spiroborate anion-based inorganic electrolytes and ionic liquids (ILs) have fascinating electrochemical and tribological properties and have received widespread attention in industrial applications. The molecular chiralities of spiroborate anions have a significant effect on the microstructures and macroscopic functionalities of these ionic materials in application and thus deserve fundamental consideration. In the current work, we performed quantum chemistry calculations to address the binding strength and coordination structures of chiral bis(mandelato)borate ([BMB]) anions with representative alkali metal ions, as well as the electronic properties of alkali metal ion-[BMB] ion pair complexes. The optimized [BMB] conformers are categorized into V-shaped, bent, and twisted structures with varied electrostatic potential contours and conformational energies and distinct alkali metal ion-[BMB] binding structures. Alkali metal ions have additional associations with phenyl groups in V-shaped [BMB] conformers owing to preferential cation-π interactions. Furthermore, the effects of the molecular chiralities of [BMB] anions on the thermodynamics and microstructural properties of tetraalkylphosphonium [BMB] ILs were studied by performing extensive atomistic interactions. Oxygen atoms in [BMB] anions have competitive hydrogen bonding interactions with hydrogen atoms in cations depending on the molecular chiralities and steric hindrance effects of [BMB] anions. However, the molecular chiralities of [BMB] anions have a negligible effect on the liquid densities of tetraalkylphosphonium [BMB] ILs and the spatial distributions of boron atoms in anions around phosphorous atoms in cations. Enlarging tetraalkylphosphonium cation sizes leads to enhanced cation-anion intermolecular hydrogen bonding and Coulombic interactions due to enhanced segregation of polar groups in apolar networks in heterogeneous IL matrices, as verified by scattering structural functions.
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Affiliation(s)
- Han-Wen Pei
- Arrhenius Laboratory, Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden
| | - Bin Li
- School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai, China
| | - Aatto Laaksonen
- Arrhenius Laboratory, Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden
- State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing, China
- Centre of Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry, Iasi, Romania
| | - Yong-Lei Wang
- Arrhenius Laboratory, Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden
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17
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Sha M, Ma X, Li N, Luo F, Zhu G, Fayer MD. Dynamical properties of a room temperature ionic liquid: Using molecular dynamics simulations to implement a dynamic ion cage model. J Chem Phys 2019; 151:154502. [PMID: 31640381 DOI: 10.1063/1.5126231] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The transport behavior of ionic liquids (ILs) is pivotal for a variety of applications, especially when ILs are used as electrolytes. Many aspects of the transport dynamics of ILs remain to be understood. Here, a common ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BmimNTf2), was studied with molecular dynamics simulations. The results show that BmimNTf2 displays typical structural relaxation, subdiffusive behavior, and a breakdown of the Stokes-Einstein diffusion relation as in glass-forming liquids. In addition, the simulations show that the translational dynamics, reorientation dynamics, and structural relaxation dynamics are well described by the Vogel-Fulcher-Tammann equation like fragile glass forming liquids. Building on previous work that employed ion cage models, it was found that the diffusion dynamics of the cations and anions were well described by a hopping process random walk where the step time is the ion cage lifetime obtained from the cage correlation function. Detailed analysis of the ion cage structures indicated that the electrostatic potential energy of the ion cage dominates the diffusion dynamics of the caged ion. The ion orientational relaxation dynamics showed that ion reorientation is a necessary step for ion cage restructuring. The dynamic ion cage model description of ion diffusion presented here may have implications for designing ILs to control their transport behavior.
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Affiliation(s)
- Maolin Sha
- Department of Physics and Materials Engineering, Hefei Normal University, Hefei 230061, China
| | - Xiaohang Ma
- Department of Physics and Materials Engineering, Hefei Normal University, Hefei 230061, China
| | - Na Li
- Department of Chemistry and Chemical Engineering, Hefei Normal University, Hefei 230061, China
| | - Fabao Luo
- Department of Chemistry and Chemical Engineering, Hefei Normal University, Hefei 230061, China
| | - Guanglai Zhu
- Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu 241000, China
| | - Michael D Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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18
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Nemoto F, Kofu M, Nagao M, Ohishi K, Takata SI, Suzuki JI, Yamada T, Shibata K, Ueki T, Kitazawa Y, Watanabe M, Yamamuro O. Neutron scattering studies on short- and long-range layer structures and related dynamics in imidazolium-based ionic liquids. J Chem Phys 2018; 149:054502. [PMID: 30089384 DOI: 10.1063/1.5037217] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Alkyl-methyl-imidazolium ionic liquids CnmimX (n: alkyl-carbon number, X: anion) have short-range layer structures consisting of ionic and neutral (alkylchain) domains. To investigate the temperature dependences of the interlayer, interionic group, and inter-alkylchain correlations, we have measured the neutron diffraction (ND) of C16mimPF6, C9.5mimPF6, and C8mimPF6 in the temperature region from 4 K to 470 K. The quasielastic neutron scattering (QENS) of C16mimPF6 was also measured to study the dynamics of each correlation. C16mimPF6 shows a first-order transition between the liquid (L) and liquid crystalline (LC) phases at Tc = 394 K. C8mimPF6 exhibits a glass transition at Tg = 200 K. C9.5mimPF6, which is a 1:3 mixture between C8mimPF6 and C10mimPF6, has both transitions at Tc = 225 K and Tg = 203 K. In the ND experiments, all samples exhibit three peaks corresponding to the correlations mentioned above. The widths of the interlayer peak at ca. 0.2 Å-1 changed drastically at the L-LC transitions, while the interionic peaks at ca. 1 Å-1 exhibited a small jump at Tc. The peak position and area of the three peaks did not change much at the transition. The structural changes were minimal at Tg. The QENS experiments demonstrated that the relaxation time of the interlayer motion increased tenfold at Tc, while those of other motions were monotonous in the whole temperature region. The structural and dynamical changes mentioned above are characteristic of the L-LC transition in imidazolium-based ionic liquids.
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Affiliation(s)
- Fumiya Nemoto
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Maiko Kofu
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Michihiro Nagao
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899-6102, USA
| | - Kazuki Ohishi
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), IQBRC Bldg., 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan
| | - Shin-Ichi Takata
- J-PARC Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Naka, Ibaraki 319-1195, Japan
| | - Jun-Ichi Suzuki
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), IQBRC Bldg., 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan
| | - Takeshi Yamada
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), IQBRC Bldg., 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan
| | - Kaoru Shibata
- J-PARC Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Naka, Ibaraki 319-1195, Japan
| | - Takeshi Ueki
- Department of Materials Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Yuzo Kitazawa
- Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama, Kanagawa 240-8501, Japan
| | - Masayoshi Watanabe
- Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama, Kanagawa 240-8501, Japan
| | - Osamu Yamamuro
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
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19
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Kusakabe K, Mitsutake Y, Michida W, Sakuragi M. Preparation of Mesoporous Titania Using a Sol–Gel Method in a Deep Eutectic Solvent. JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 2018. [DOI: 10.1252/jcej.17we342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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20
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Wang YL. Competitive Microstructures Versus Cooperative Dynamics of Hydrogen Bonding and π-Type Stacking Interactions in Imidazolium Bis(oxalato)borate Ionic Liquids. J Phys Chem B 2018; 122:6570-6585. [DOI: 10.1021/acs.jpcb.8b02899] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yong-Lei Wang
- Department of Chemistry, Stanford University,
Stanford, California 94305, United States
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21
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Wang YL, Zhu YL, Lu ZY, Laaksonen A. Electrostatic interactions in soft particle systems: mesoscale simulations of ionic liquids. SOFT MATTER 2018; 14:4252-4267. [PMID: 29780992 DOI: 10.1039/c8sm00387d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Computer simulations provide a unique insight into the microscopic details, molecular interactions and dynamic behavior responsible for many distinct physicochemical properties of ionic liquids. Due to the sluggish and heterogeneous dynamics and the long-ranged nanostructured nature of ionic liquids, coarse-grained meso-scale simulations provide an indispensable complement to detailed first-principles calculations and atomistic simulations allowing studies over extended length and time scales with a modest computational cost. Here, we present extensive coarse-grained simulations on a series of ionic liquids of the 1-alkyl-3-methylimidazolium (alkyl = butyl, heptyl-, and decyl-) family with Cl, [BF4], and [PF6] counterions. Liquid densities, microstructures, translational diffusion coefficients, and re-orientational motion of these model ionic liquid systems have been systematically studied over a wide temperature range. The addition of neutral beads in cationic models leads to a transition of liquid morphologies from dispersed apolar beads in a polar framework to that characterized by bi-continuous sponge-like interpenetrating networks in liquid matrices. Translational diffusion coefficients of both cations and anions decrease upon lengthening of the neutral chains in the cationic models and by enlarging molecular sizes of the anionic groups. Similar features are observed in re-orientational motion and time scales of different cationic models within the studied temperature range. The comparison of the liquid properties of the ionic systems with their neutral counterparts indicates that the distinctive microstructures and dynamical quantities of the model ionic liquid systems are intrinsically related to Coulombic interactions. Finally, we compared the computational efficiencies of three linearly scaling O(N log N) Ewald summation methods, the particle-particle particle-mesh method, the particle-mesh Ewald summation method, and the Ewald summation method based on a non-uniform fast Fourier transform technique, to calculate electrostatic interactions. Coarse-grained simulations were performed using the GALAMOST and the GROMACS packages and hardware efficiently utilizing graphics processing units on a set of extended [1-decyl-3-methylimidazolium][BF4] ionic liquid systems of up to 131 072 ion pairs.
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Affiliation(s)
- Yong-Lei Wang
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
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22
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Casalegno M, Raos G, Appetecchi GB, Passerini S, Castiglione F, Mele A. From Nanoscale to Microscale: Crossover in the Diffusion Dynamics within Two Pyrrolidinium-Based Ionic Liquids. J Phys Chem Lett 2017; 8:5196-5202. [PMID: 28976762 DOI: 10.1021/acs.jpclett.7b02431] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Knowledge of the ion motion in room temperature ionic liquids (RTILs) is critical for their applications in a number of fields, from lithium batteries to dye-sensitized solar cells. Experiments on a limited number of RTILs have shown that on macroscopic time scales the ions typically undergo conventional, Gaussian diffusion. On shorter time scales, however, non-Gaussian behavior has been observed, similar to supercooled fluids, concentrated colloidal suspensions, and more complex systems. Here we characterize the diffusive motion of ionic liquids based on the N-butyl-N-methylpyrrolidinium (PYR14) cation and bis(trifluoro methanesulfonyl)imide (TFSI) or bis(fluorosulfonyl)imide (FSI) anions. A combination of pulsed gradient spin-echo (PGSE) NMR experiments and molecular dynamics (MD) simulations demonstrates a crossover from subdiffusive behavior to conventional Gaussian diffusion at ∼10 ns. The deconvolution of molecular displacements into a continuous spectrum of diffusivities shows that the short-time behavior is related to the effects of molecular caging. For PYR14FSI, we identify the change of short-range ion-counterion associations as one possible mechanism triggering long-range displacements.
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Affiliation(s)
- Mosè Casalegno
- Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano , Piazza L. Da Vinci, 32, 20133 Milano, Italy
| | - Guido Raos
- Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano , Piazza L. Da Vinci, 32, 20133 Milano, Italy
| | - Giovanni Battista Appetecchi
- ENEA, Italian National Agency for New Technology, Energy and Sustainable Economic Development, Materials and Physicochemical Processes Laboratory , Via Anguillarese 301, 00196 Rome, Italy
| | - Stefano Passerini
- Helmholtz Institute Ulm, Karlsruhe Institute of Technology , Helmholtzstrasse 11, 89081 Ulm, Germany
- Karlsruhe Institute of Technology , P.O. Box 3640, 76131 Karlsruhe, Germany
| | - Franca Castiglione
- Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano , Piazza L. Da Vinci, 32, 20133 Milano, Italy
| | - Andrea Mele
- Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano , Piazza L. Da Vinci, 32, 20133 Milano, Italy
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