Dynamic properties of water molecules in ionic liquid/water mixture with various alkyl chain length

Kaneko, Kazuyoshi; Saihara, Koji; Masuda, Yuichi; Yoshimura, Yukihiro; Shimizu, Akio

doi:10.1016/j.molliq.2018.05.043

Cited by 23 publications

(27 citation statements)

References 35 publications

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“…For ionic molecules, the mobilities of ammonium-based cation and BF 4 anion are further slow, and the corresponding self-diffusion coefficients of D c and D a are of the order of 10 −13 to 10 −12 m 2 /s. We note that while D w / D c remains unchanged with an increase of c w , D w / D a reduces from 72 ( c w = 0.13 M) to 15 ( c w = 3.32 M) as experimentally reported in the mixtures of 1-decyl-3-methylimidazolium tetrafluoroborate and water ( 25 ). The addition of water molecules enhances the diffusivity of BF 4 anions, which contributes to an increase of the ionic conductivity.…”

Section: Resultssupporting

confidence: 77%

“…In the ILC nanochannels, water molecule diffuses faster than the ammonium-based cation and BF 4 anion, and the self-diffusion coefficient D w is of the order of 10 −12 to 10 −10 m 2 /s depending on c w . The low diffusivity is sufficiently reasonable since confined water in electrolytes gives slow mobility as observed in ionic liquids ( 25 , 46 ) and in the vicinity of rod-like polyelectrolytes ( 64 , 65 ). The counterion condensation ( 32 , 33 ) also supports the present results that the ILC nanochannels slow down the dynamics of confined waters due to the existence of condensed and tightly bound counterions via the high ion density of nanochannels (see section S4).…”

Section: Resultsmentioning

confidence: 94%

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Molecular insights on confined water in the nanochannels of self-assembled ionic liquid crystal

et al. 2021

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Self-assembled ionic liquid crystals can transport water and ions via the periodic nanochannels, and these materials are promising candidates as water treatment membranes. Molecular insights on the water transport process are, however, less investigated because of computational difficulties of ionic soft matters and the self-assembly. Here we report specific behavior of water molecules in the nanochannels by using the self-consistent modeling combining density functional theory and molecular dynamics and the large-scale molecular dynamics calculation. The simulations clearly provide the one-dimensional (1D) and 3D-interconnected nanochannels of self-assembled columnar and bicontinuous structures, respectively, with the precise mesoscale order observed by x-ray diffraction measurement. Water molecules are then confined inside the nanochannels with the formation of hydrogen bonding network. The quantitative analyses of free energetics and anisotropic diffusivity reveal that, the mesoscale geometry of 1D nanodomain profits the nature of water transport via advantages of dissolution and diffusion mechanisms inside the ionic nanochannels.

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Section: Resultssupporting

confidence: 77%

Section: Resultsmentioning

confidence: 94%

Molecular insights on confined water in the nanochannels of self-assembled ionic liquid crystal

et al. 2021

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“…Extensive experimental characterizations (NMR, ,,,− infrared and Raman spectroscopies, ,,− X-ray and neutron scattering spectroscopies, ,,,, etc. ), theoretical studies, , DFT calculations, ,, and atomistic simulations ,,,− ,− ,,,− have been performed to characterize phase behavior changes when mixing ILs with water.…”

Section: Ionic Liquid–molecular Solvent Mixturesmentioning

confidence: 99%

“…Most water molecules are scattered in IL matrixes and are preferentially coordinated with ion species nearby, leading to the local ionic structures described by solute-shared ion pairs (Figure A). The restricted spatial configuration of water molecules in IL–water mixtures results in their constrained rotational relaxation within a cone of angles due to their dual feature in coordinating both cations and anions via HB interactions and a significant increase in translational diffusions of ion species in mixtures as water concentration increases (Figure E). ,,,, …”

Section: Ionic Liquid–molecular Solvent Mixturesmentioning

confidence: 99%

Microstructural and Dynamical Heterogeneities in Ionic Liquids

et al. 2020

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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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“…Several experimental methods have been applied to study the structure and dynamics of both neat IL and its mixtures with molecular solvents, particularly for phase-behaviour of water-IL mixtures, from DFT calculations [129][130][131] and molecular dynamics (MD) simulations [132][133][134], to spectroscopic techniques like NMR [32,106,[135][136][137][138], Small-Angle Neutron Scattering (SANS) [139,140], infrared and RAMAN spectroscopy [141][142][143][144][145].…”

Section: Water Effectmentioning

confidence: 99%

Revisiting Ionic Liquid Structure-Property Relationship: A Critical Analysis

Silva

Zanatta

Ferreira

et al. 2020

IJMS

103

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In the last few years, ionic liquids (ILs) have been the focus of extensive studies concerning the relationship between structure and properties and how this impacts their application. Despite a large number of studies, several topics remain controversial or not fully answered, such as: the existence of ion pairs, the concept of free volume and the effect of water and its implications in the modulation of ILs physicochemical properties. In this paper, we present a critical review of state-of-the-art literature regarding structure–property relationship of ILs, we re-examine analytical theories on the structure–property correlations and present new perspectives based on the existing data. The interrelation between transport properties (viscosity, diffusion, conductivity) of IL structure and free volume are analysed and discussed at a molecular level. In addition, we demonstrate how the analysis of microscopic features (particularly using NMR-derived data) can be used to explain and predict macroscopic properties, reaching new perspectives on the properties and application of ILs.

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Dynamic properties of water molecules in ionic liquid/water mixture with various alkyl chain length

Cited by 23 publications

References 35 publications

Molecular insights on confined water in the nanochannels of self-assembled ionic liquid crystal

Molecular insights on confined water in the nanochannels of self-assembled ionic liquid crystal

Microstructural and Dynamical Heterogeneities in Ionic Liquids

Revisiting Ionic Liquid Structure-Property Relationship: A Critical Analysis

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