1
|
Rush K, Islam MM, Nawagamuwage SU, Marzette J, Browne O, Foy K, Reyes K, Hoang M, Nguyen C, Walker A, Ferrufino Amador S, Riglioni E, Rubtsov IV, Riley K, Dutta S. Hydrogen-Bonded Complexes in Binary Mixture of Imidazolium-Based Ionic Liquids with Organic Solvents. J Phys Chem B 2023; 127:8916-8925. [PMID: 37812742 PMCID: PMC10591470 DOI: 10.1021/acs.jpcb.3c05152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/20/2023] [Indexed: 10/11/2023]
Abstract
Though local structures in ionic liquids are dominated by strong Coulomb forces, directional hydrogen bonds can also influence the physicochemical properties of imidazolium-based ionic liquids. In particular, the C-2 position of the imidazolium cation is acidic and can bind with suitable hydrogen bond acceptor sites of molecular solvents dissolved in imidazolium-based ionic liquids. In this report, we identify hydrogen-bonded microenvironments of the model ionic liquid, 1-ethyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate, and the changes that occur when molecular solvents are dissolved in it by using a C-D infrared reporter at the C-2 position of the cation. Our linear and nonlinear infrared experiments, along with computational studies, indicate that the molecular solvent dimethyl sulfoxide can form strong hydrogen-bonded dimers with the cation of the ionic liquid at the C-2 position. In contrast, acetone, which is also a hydrogen bond acceptor similar to dimethyl sulfoxide, does not show evidence of cation-solvent hydrogen-bonded conformers at the C-2 position. The outcome of our study on a broad scale strengthens the importance of cation-solute interactions in ionic liquids.
Collapse
Affiliation(s)
- Kaiyah Rush
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| | - Md Muhaiminul Islam
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | | | - Jorden Marzette
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| | - Olivia Browne
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| | - Kayla Foy
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| | - Khale’ Reyes
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| | - Melissa Hoang
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| | - Catherine Nguyen
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| | - Alexis Walker
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| | - Susana Ferrufino Amador
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| | - Emanuela Riglioni
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| | - Igor V. Rubtsov
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Kevin Riley
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| | - Samrat Dutta
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 78125, United States
| |
Collapse
|
2
|
An R, Laaksonen A, Wu M, Zhu Y, Shah FU, Lu X, Ji X. Atomic force microscopy probing interactions and microstructures of ionic liquids at solid surfaces. NANOSCALE 2022; 14:11098-11128. [PMID: 35876154 DOI: 10.1039/d2nr02812c] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Ionic liquids (ILs) are room temperature molten salts that possess preeminent physicochemical properties and have shown great potential in many applications. However, the use of ILs in surface-dependent processes, e.g. energy storage, is hindered by the lack of a systematic understanding of the IL interfacial microstructure. ILs on the solid surface display rich ordering, arising from coulombic, van der Waals, solvophobic interactions, etc., all giving near-surface ILs distinct microstructures. Therefore, it is highly important to clarify the interactions of ILs with solid surfaces at the nanoscale to understand the microstructure and mechanism, providing quantitative structure-property relationships. Atomic force microscopy (AFM) opens a surface-sensitive way to probe the interaction force of ILs with solid surfaces in the layers from sub-nanometers to micrometers. Herein, this review showcases the recent progress of AFM in probing interactions and microstructures of ILs at solid interfaces, and the influence of IL characteristics, surface properties and external stimuli is thereafter discussed. Finally, a summary and perspectives are established, in which, the necessities of the quantification of IL-solid interactions at the molecular level, the development of in situ techniques closely coupled with AFM for probing IL-solid interfaces, and the combination of experiments and simulations are argued.
Collapse
Affiliation(s)
- Rong An
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Aatto Laaksonen
- Energy Engineering, Division of Energy Science, Luleå University of Technology, 97187 Luleå, Sweden.
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden
- Center of Advanced Research in Bionanoconjugates and Biopolymers, "Petru Poni" Institute of Macromolecular Chemistry, Iasi 700469, Romania
- State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Muqiu Wu
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Yudan Zhu
- State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Faiz Ullah Shah
- Chemistry of Interfaces, Luleå University of Technology, 97187 Luleå, Sweden
| | - Xiaohua Lu
- State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Xiaoyan Ji
- Energy Engineering, Division of Energy Science, Luleå University of Technology, 97187 Luleå, Sweden.
| |
Collapse
|
3
|
Order beyond a monolayer: The story of two self-assembled 4,4′-bipyridine layers on the Sb(111) | ionic liquid interface. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.140468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
4
|
Kobayashi T, Smiatek J, Fyta M. Probing the distribution of ionic liquid mixtures at charged and neutral interfaces via simulations and lattice-gas theory. Phys Chem Chem Phys 2022; 24:16471-16483. [PMID: 35766260 DOI: 10.1039/d2cp01346k] [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
Room temperature ionic liquid solutions confined between neutral and charged surfaces are investigated by means of atomistic Molecular Dynamics simulations. We study 1-ethyl-3-methylimidazolium dicyanamide ([EMIm]+[DCA]-) in water or dimethylsulfoxide (DMSO) mixtures in confinement between two interfaces. The analysis is based on the comparison of the molecular species involved and the charged state of the surfaces. Focus is given on the influence of different water/DMSO concentrations on the microstructuring and accumulation of each species. Thermodynamic aspects, such as the entropic contributions in the observed trends are obtained from the simulations using a lattice-gas theory. The results clearly underline the differences in these properties for the water and DMSO mixtures and unravel the underlying mechanisms and inherent details. We were able to pinpoint the importance of the size and the relative permittivity of the molecules in guiding their microstructuring in the vicinity of the surfaces, as well as their interactions with the latter, i.e. the solute-surface interactions. The influence of water and DMSO on the overscreening at charged interfaces is also discussed. The analysis on the molecular accumulation at the interfaces allows us to predict whether the accumulation is entropy or enthalpy driven, which has an impact in the removal of the molecular species from the surfaces. We discuss the impact of this work in providing an essential understanding towards a careful design of electrochemical elements.
Collapse
Affiliation(s)
- Takeshi Kobayashi
- Institute for Computational Physics, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany.
| | - Jens Smiatek
- Institute for Computational Physics, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany.
| | - Maria Fyta
- Institute for Computational Physics, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany.
| |
Collapse
|
5
|
Kim T, Choi H, Choi H, Kim JS, Kim DH, Jeong U. Skin-inspired electrochemical tactility and luminescence. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.140259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
6
|
Miranda-Quintana RA, Smiatek J. Specific Ion Effects in Different Media: Current Status and Future Challenges. J Phys Chem B 2021; 125:13840-13849. [PMID: 34918938 DOI: 10.1021/acs.jpcb.1c07957] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We discuss the current state of research as well as the future challenges for a deeper understanding of specific ion effects in protic and aprotic solvents as well as various additional media. Despite recent interest in solute or interfacial effects, we focus exclusively on the specific properties of ions in bulk electrolyte solutions. Corresponding results show that many mechanisms remain unknown for these simple media, although theoretical, computational, and experimental studies have provided some insights into explaining individual observations. In particular, the importance of local interactions and electronic properties is emphasized, which enabled a more consistent interpretation of specific ion effects over the past years. Despite current insufficient knowledge, we also discuss future challenges in relation to dynamic properties as well as the influence of different concentrations, different solvents, and solute contributions to gain a deeper understanding of specific ion effects for technological applications.
Collapse
Affiliation(s)
- Ramón Alain Miranda-Quintana
- Department of Chemistry and Quantum Theory Project, University of Florida, Gainesville, Florida 32611, United States
| | - Jens Smiatek
- Institute for Computational Physics, University of Stuttgart, D-70569 Stuttgart, Germany.,Digitalization Development Biologicals CMC, Boehringer Ingelheim Pharma GmbH & Co. KG, D-88397 Biberach (Riss), Germany
| |
Collapse
|
7
|
Gao Q, Tsai W, Balke N. In situ and operando force‐based atomic force microscopy for probing local functionality in energy storage materials. ELECTROCHEMICAL SCIENCE ADVANCES 2021. [DOI: 10.1002/elsa.202100038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Qiang Gao
- Department of Chemistry University of Wisconsin‐Madison Madison Wisconsin USA
| | - Wan‐Yu Tsai
- Chemical Science Division Oak Ridge National Laboratory Oak Ridge Tennessee USA
| | - Nina Balke
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge Tennessee USA
| |
Collapse
|
8
|
Pilkington GA, Oleshkevych A, Pedraz P, Watanabe S, Radiom M, Reddy AB, Vorobiev A, Glavatskih S, Rutland MW. Electroresponsive structuring and friction of a non-halogenated ionic liquid in a polar solvent: effect of concentration. Phys Chem Chem Phys 2020; 22:19162-19171. [PMID: 32812565 DOI: 10.1039/d0cp02736g] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Neutron reflectivity (NR) measurements have been employed to study the interfacial structuring and composition of electroresponsive boundary layers formed by an ionic liquid (IL) lubricant at an electrified gold interface when dispersed in a polar solvent. The results reveal that both the composition and extent of the IL boundary layers intricately depend on the bulk IL concentration and the applied surface potential. At the lowest concentration (5% w/w), a preferential adsorption of the IL cation at the gold electrode is observed, which hinders the ability to electro-induce changes in the boundary layers. In contrast, at higher IL bulk concentrations (10 and 20% w/w), the NR results reveal a significantly larger concentration of the IL ions at the gold interface that exhibit significantly greater electroresponsivity, with clear changes in the layer composition and layer thickness observed for different potentials. In complementary atomic force microscopy (AFM) measurements on an electrified gold surface, such IL boundary layers are demonstrated to provide excellent friction reduction and electroactive friction (known as tribotronics). In agreement with the NR results obtained, clear concentration effects are also observed. Together such results provide valuable molecular insight into the electroactive structuring of ILs in solvent mixtures, as well as provide mechanistic understanding of their tribotronic behaviours.
Collapse
Affiliation(s)
- Georgia A Pilkington
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | - Anna Oleshkevych
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | - Patricia Pedraz
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | - Seiya Watanabe
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | - Milad Radiom
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | - Akepati Bhaskar Reddy
- System and Component Design, Department of Machine Design, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Alexei Vorobiev
- Department of Physics and Astronomy, Division of Materials Physics, Uppsala University, Uppsala, Sweden
| | - Sergei Glavatskih
- System and Component Design, Department of Machine Design, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden and Department of Electromechanical, Systems and Metal Engineering, Ghent University, B-9052 Ghent, Belgium
| | - Mark W Rutland
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden. and Surfaces, Processes and Formulation, RISE Research Institutes of Sweden, SE-100 44 Stockholm, Sweden
| |
Collapse
|
9
|
De Sarkar S, Mitra S, Ghosh SK. Relating the physical properties of aqueous solutions of ionic liquids with their chemical structures. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2020; 43:55. [PMID: 32816131 DOI: 10.1140/epje/i2020-11974-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
The physical properties of an aqueous solution of a macromolecule primarily depend on its chemical structure and the mesoscopic aggregates formed by many of such molecules. Ionic liquids (ILs) are the macromolecules that have caught significant research interests for their enormous industrial and biomedical applications. In the present paper, the physical properties, such as density, viscosity, ionic conductivity of aqueous solutions of various ILs, have been investigated. These properties are found to systematically depend on the shape and size of the anion and the cation along with the solution concentration. The ionic conductivity and viscosity behavior of the solutions do not strictly follow the Walden rule that relates the conductivity to the viscosity of the solution. However, the modified Walden rule could explain the behavior. A simple calculation based on the geometry of a given molecule could shed the light on the observed results.
Collapse
Affiliation(s)
- Shuverthi De Sarkar
- Department of Physics, School of Natural Sciences, Shiv Nadar University, NH 92, 201314, Tehsil Dadri, G. B. Nagar, Uttar Pradesh, India
| | - Saheli Mitra
- Department of Physics, School of Natural Sciences, Shiv Nadar University, NH 92, 201314, Tehsil Dadri, G. B. Nagar, Uttar Pradesh, India.
| | - Sajal K Ghosh
- Department of Physics, School of Natural Sciences, Shiv Nadar University, NH 92, 201314, Tehsil Dadri, G. B. Nagar, Uttar Pradesh, India.
| |
Collapse
|
10
|
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: 192] [Impact Index Per Article: 48.0] [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.
Collapse
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
| |
Collapse
|
11
|
Tan BH, Zhang J, Jin J, Ooi CH, He Y, Zhou R, Ostrikov K, Nguyen NT, An H. Direct Measurement of the Contents, Thickness, and Internal Pressure of Molybdenum Disulfide Nanoblisters. NANO LETTERS 2020; 20:3478-3484. [PMID: 32271023 DOI: 10.1021/acs.nanolett.0c00398] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nanoblisters have attracted attention due to their ability to controllably modulate the properties of two-dimensional materials. The accurate measurement or estimation of their properties is nontrivial and largely based on Hencky's theory. However, these estimates require a priori knowledge of material properties and propagate large errors. Here we show, through a systematic atomic force microscopy study, several strategies that lead to vastly enhanced characterization of nanoblisters. First, we find that nanoblisters may contain both liquid and gas, resolving an ongoing debate in the literature. Second, we demonstrate how to definitively determine the membrane thickness of a nanoblister and show that Hencky's theory can only reliably predict membrane thicknesses for small aspect ratios and small membrane thicknesses. Third, we develop a novel technique to measure the internal pressures of nanoblisters, which quantitatively agrees with Hencky's theory but carries a 1 order smaller propagated error.
Collapse
Affiliation(s)
- Beng Hau Tan
- Low Energy Electronic Systems, Singapore-MIT Alliance for Research and Technology, 1 Create Way, 138602 Singapore
| | - Jun Zhang
- Queensland Micro and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia
| | - Jing Jin
- Queensland Micro and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia
| | - Chin Hong Ooi
- Queensland Micro and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia
| | - Yi He
- School of National Defence Science & Technology, Southwest University of Science and Technology, Mianyang, 621010, PR China
| | - Renwu Zhou
- School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, NSW 2006, Australia
| | - Kostya Ostrikov
- School of Chemistry and Physics, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Nam-Trung Nguyen
- Queensland Micro and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia
| | - Hongjie An
- Queensland Micro and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia
| |
Collapse
|
12
|
Pivnic K, Bresme F, Kornyshev AA, Urbakh M. Structural Forces in Mixtures of Ionic Liquids with Organic Solvents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15410-15420. [PMID: 31657581 DOI: 10.1021/acs.langmuir.9b02121] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Using molecular dynamics simulations, we study the impact of electrode charging and addition of solvent (acetonitrile, ACN) on structural forces of the BMIM PF6 ionic liquid (IL) confined by surfaces at nanometer separations. We establish relationships between the structural forces and the microscopic structure of the confined liquid. Depending on the structural arrangements of cations and anions across the nanofilm, the load-induced squeeze-out of liquid layers occurs via one-layer or bilayer steps. The cations confined between charged plates orient with their aliphatic chain perpendicular to the surface planes and link two adjacent IL layers. These structures facilitate the squeeze-out of single layers. For both pure IL and IL-ACN mixtures, we observe a strong dependence of nanofilm structure on the surface charge density, which affects the simulated pressure-displacement curves. Addition of solvent to the IL modifies the layering in the confined film. At high electrode charges and high dilution of IL (below 10% molar fraction), the layered structure of the nanofilm is less well defined. We predict a change in the squeeze-out mechanism under pressure, from a discontinuous squeeze-out (for high IL concentrations) to an almost continuous one (for low IL concentrations). Importantly, our simulations show that charged electrodes are coated with ions even at low IL concentrations. These ion-rich layers adjacent to the charged plate surfaces are not squeezed out even under very high normal pressures of ∼5 GPa. Hence, we demonstrate the high performance of IL-solvent mixtures to protect surfaces from wear and to provide lubrication at high loads.
Collapse
Affiliation(s)
- Karina Pivnic
- School of Chemistry, The Sackler Center for Computational Molecular and Materials Science , Tel Aviv University , Tel Aviv 6997801 , Israel
| | - Fernando Bresme
- Department of Chemistry , Molecular Sciences Research Hub, Imperial College London , W12 0BZ 2AZ London , United Kingdom
- Thomas Young Centre for Theory and Simulation of Materials , Imperial College London , South Kensington Campus , London SW7 2AZ , United Kingdom
| | - Alexei A Kornyshev
- Department of Chemistry , Molecular Sciences Research Hub, Imperial College London , W12 0BZ 2AZ London , United Kingdom
- Thomas Young Centre for Theory and Simulation of Materials , Imperial College London , South Kensington Campus , London SW7 2AZ , United Kingdom
| | - Michael Urbakh
- School of Chemistry, The Sackler Center for Computational Molecular and Materials Science , Tel Aviv University , Tel Aviv 6997801 , Israel
| |
Collapse
|
13
|
Merz S, Jakes P, Taranenko S, Eichel RA, Granwehr J. Dynamics of [Pyr 13][Tf 2N] ionic liquid confined to carbon black. Phys Chem Chem Phys 2019; 21:17018-17028. [PMID: 31348470 DOI: 10.1039/c9cp02651g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The intrinsic ionic nature of room temperature ionic liquids (RTILs) bears the potential to replace classical aqueous electrolytes in electrochemical applications, for example in metal-air batteries. For a systematic adjustment of RTIL properties in porous cathodes, the ionic arrangement under confinement is of prime importance. Using spectrally resolved pulsed gradient stimulated echo nuclear magnetic resonance (PGSTE-NMR) and spin-lattice NMR relaxation time (T1) distributions, the dynamics of 1-methyl-1-propylpyrrolidiniumbis(trifluoromethylsulfonyl)imide ([Pyr13][Tf2N]) confined to carbon black were investigated. A considerable dependence of the [PYR13] mobility on the loading fraction of the carbon black pore space was found. There is evidence for a preferential layering of the RTIL adjacent to the carbon surface and a dependence of the ionic configuration on the local structure of the carbon surface. The inversion efficiency of inversion-recovery T1 data indicates a quasi-stationary layer at the carbon surface with solid-like properties, where the bulk-like properties of the RTIL are adopted as the distance to the surface increases. From the NMR diffusion data an intermediate layer between the quasi-stationary and the bulk-like RTIL is evident. This layer shows a particularly strong pore space loading dependence. While it has an anisotropic, two-dimensional mobility with reduced diffusion perpendicular to the surface at any loading, when it interfaces a gas phase at low loading its mobility is higher than bulk diffusion by up to an order of magnitude and chemical exchange with other layers is low. This layer appears to be of particular importance for the ion exchange between RTIL environments with different spacing from the carbon surface and hence crucial for the overall dynamics of RTILs in the investigated porous environment.
Collapse
Affiliation(s)
- Steffen Merz
- Forschungszentrum Juelich, Institute of Energy and Climate Research, Fundamental Electrochemistry (IEK-9), 52425 Juelich, Germany.
| | - Peter Jakes
- Forschungszentrum Juelich, Institute of Energy and Climate Research, Fundamental Electrochemistry (IEK-9), 52425 Juelich, Germany.
| | - Svitlana Taranenko
- Forschungszentrum Juelich, Institute of Energy and Climate Research, Fundamental Electrochemistry (IEK-9), 52425 Juelich, Germany.
| | - Rüdiger-A Eichel
- Forschungszentrum Juelich, Institute of Energy and Climate Research, Fundamental Electrochemistry (IEK-9), 52425 Juelich, Germany. and RWTH Aachen University, Institute of Physical Chemistry, 52074 Aachen, Germany
| | - Josef Granwehr
- Forschungszentrum Juelich, Institute of Energy and Climate Research, Fundamental Electrochemistry (IEK-9), 52425 Juelich, Germany. and RWTH Aachen University, Institute of Technical and Macromolecular Chemistry, 52074 Aachen, Germany
| |
Collapse
|
14
|
Alcalde R, Atilhan M, Aparicio S. Intermolecular forces in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide + ethanol mixtures. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.02.064] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|