1
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Eliasen KL, Gabriel J, Blochowicz T, Gainaru CP, Christensen TE, Niss K. What is the origin of slow relaxation modes in highly viscous ionic liquids? J Chem Phys 2024; 161:034506. [PMID: 39012811 DOI: 10.1063/5.0215661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 06/27/2024] [Indexed: 07/18/2024] Open
Abstract
Room temperature ionic liquids (RTILs) are molten salts consisting entirely of ions and have over the past decades gained increased interest due to their high potential in applications. These structurally complex systems often display multiple relaxation modes in the response functions at lower frequencies, hinting to complex underlying mechanisms. While the existence of these multimodal spectra in the shear mechanical, dielectric, and light scattering response of RTILs has been confirmed multiple times, controversy still surrounds the origin. This paper, therefore, aims to provide additional insights into the multimodal spectra seen in RTILs by presenting new shear mechanical results on seven different RTILs: Pyr1n-TFSI with n = 4, 6, and 8; Pyr18-TFSI mixed with Li-TFSI in two high concentrations; and Cn-mim-BF4 with n = 3 and 8. Dynamic depolarized light scattering was also measured on one of the Pyr18-TFSI Li-salt mixtures. These specific cases were analyzed in detail and put into a bigger perspective together with an overview of the literature. Recent literature offers two specific explanations for the origin of the multimodal shear mechanical spectra: (1) cation-anion time scale separation or (2) combined cation-anion relaxation in addition to a dynamic signal from mesoscale aggregates at lower frequencies. However, neither of these two pictures can consistently explain all the results on different ionic liquids. Instead, we conclude that the origin of the multimodal spectrum is system specific. This underlines the complexity of this class of liquids and shows that great care must be taken when making general conclusions based on specific cases.
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Affiliation(s)
- Kira L Eliasen
- "Glass and Time," IMFUFA, Department of Science and Environment, Roskilde University, Roskilde 4000, Denmark
| | - Jan Gabriel
- "Glass and Time," IMFUFA, Department of Science and Environment, Roskilde University, Roskilde 4000, Denmark
| | - Thomas Blochowicz
- Institut für Festkörperphysik, Technische Universität Darmstadt, Darmstadt 64289, Germany
| | - Catalin P Gainaru
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Tage E Christensen
- "Glass and Time," IMFUFA, Department of Science and Environment, Roskilde University, Roskilde 4000, Denmark
| | - Kristine Niss
- "Glass and Time," IMFUFA, Department of Science and Environment, Roskilde University, Roskilde 4000, Denmark
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2
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Yao B, Alvarez VM, Paluch M, Fedor G, McLaughlin S, McGrogan A, Swadźba-Kwaśny M, Wojnarowska Z. Crystallization Kinetics of Phosphonium Ionic Liquids: Effect of Cation Alkyl Chain Length and Thermal History. J Phys Chem B 2024; 128:6610-6621. [PMID: 38924509 PMCID: PMC11247483 DOI: 10.1021/acs.jpcb.4c01720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 06/13/2024] [Accepted: 06/14/2024] [Indexed: 06/28/2024]
Abstract
The effects of alkyl chain length on the crystallization kinetics and ion mobility of tetraalkylphosphonium, [P666,n][TFSI], (n = 2, 6, 8, and 12) ionic liquids were studied by differential scanning calorimetry (DSC) and broadband dielectric spectroscopy (BDS) over a wide temperature range. The liquid-glass transition temperature (Tg) and ion dynamics examined over a broad T range were almost insensitive to structural modifications of the phosphonium cation. In contrast, the crystallization kinetics were strongly affected by the length of the fourth alkyl chain. Furthermore, the thermal history of the sample (cold vs melt crystallization) significantly impacted the crystallization rate. It has been found that the nature of crystallization phenomena is the same across the homologous series, while the kinetic aspect differs. Finally, electric conductivity in supercooled liquid and crystalline solid phases was measured for all samples, revealing significant ionic conductivity, largely independent of the cation structure.
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Affiliation(s)
- B. Yao
- Institute
of Physics, The University of Silesia in
Katowice, 75 Pułku Piechoty 1A, Chorzów 41-500, Poland
| | - V. Morales Alvarez
- Institute
of Physics, The University of Silesia in
Katowice, 75 Pułku Piechoty 1A, Chorzów 41-500, Poland
| | - M. Paluch
- Institute
of Physics, The University of Silesia in
Katowice, 75 Pułku Piechoty 1A, Chorzów 41-500, Poland
| | - G. Fedor
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, David Keir Building, Stranmillis
Rd, Belfast, NI BT9 5AG, U.K.
| | - S. McLaughlin
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, David Keir Building, Stranmillis
Rd, Belfast, NI BT9 5AG, U.K.
| | - A. McGrogan
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, David Keir Building, Stranmillis
Rd, Belfast, NI BT9 5AG, U.K.
| | - M. Swadźba-Kwaśny
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, David Keir Building, Stranmillis
Rd, Belfast, NI BT9 5AG, U.K.
| | - Z. Wojnarowska
- Institute
of Physics, The University of Silesia in
Katowice, 75 Pułku Piechoty 1A, Chorzów 41-500, Poland
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3
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Lin ZW, Wang J, Dyakiv Y, Helbling DE, Dichtel WR. Structural Features of Styrene-Functionalized Cyclodextrin Polymers That Promote the Adsorption of Perfluoroalkyl Acids in Water. ACS APPLIED MATERIALS & INTERFACES 2024; 16:28409-28422. [PMID: 38768313 DOI: 10.1021/acsami.4c01969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Cross-linked β-cyclodextrin (β-CD) polymers are promising adsorbents for the removal of per- and polyfluoroalkyl substances (PFAS) from contaminated water sources, including contaminated groundwater, drinking water, and wastewater. We previously reported porous, styrene-functionalized β-cyclodextrin (StyDex) polymers derived from radical polymerization with vinyl comonomers. Because of the versatility of these polymerizations, StyDex polymer compositions are tunable, which facilitates efforts to establish structure-adsorption relationships and to discover improved materials. Here, we evaluate the material properties and PFAS adsorption of 20 StyDex derivatives with varied comonomer structure and loading, regiochemistry of styrene placement on the CD monomer, and CD size. A StyDex polymer containing N,N'-dimethylbutyl ammonium ions exhibited the most effective PFAS adsorption in batch experiments. Furthermore, a StyDex polymer containing β-CD exhibited size-selective host-guest interactions with perfluoroalkyl acids (PFAAs) and neutral contaminants in aqueous electrolyte when compared to similar polymers containing either α-CD or γ-CD. Polymers based on β-CD monomers with an average of seven styrene groups randomly positioned over the 21 available hydroxyl groups performed similarly to those based on a β-CD monomer functionalized regiospecifically at each of the seven 6' positions. The former β-CD monomer is prepared in a single step from unmodified β-CD, so the ability to use it without compromising performance demonstrates promise for developing economically competitive adsorbents. These results offered important insights into structure-adsorption properties of StyDex polymers and will inform the design of improved StyDex formulations.
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Affiliation(s)
- Zhi-Wei Lin
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Jieyuan Wang
- School of Civil and Environmental Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Yaryna Dyakiv
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Damian E Helbling
- School of Civil and Environmental Engineering, Cornell University, Ithaca, New York 14853, United States
| | - William R Dichtel
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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4
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Cosby T, Stachurski CD, Mantz RA, Trulove PC, Durkin DP. Elucidating the interplay of local and mesoscale ion dynamics and transport properties in aprotic ionic liquids. Phys Chem Chem Phys 2023; 25:6342-6351. [PMID: 36779353 DOI: 10.1039/d2cp05863d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ion dynamics and charge transport in 1-methyl-3-octylimidazolium ionic liquids with chloride, bromide, tetrafluoroborate, tricyanomethanide, hexafluorophosphate, triflate, tetrachloroaluminate, bis(trifluoromethylsulfonyl)imide, and heptachlorodialuminate anions are investigated by broadband dielectric spectroscopy, rheology, viscometry, and differential scanning calorimetry. A detailed analysis reveals an anion and temperature-dependent separation of characteristic molecular relaxation rates extracted from various representations of the dielectric spectra. The separation in rates extracted from the electric modulus and conductivity formalisms is interpreted as an experimental signature of significant heterogeneity in the local ion dynamics associated with the structural glass transition, viscosity, and dc ion conductivity. It is further found that the degree of dynamic heterogeneity correlates with the strengths of slow dielectric and mechanical relaxations previously attributed to the dynamics of mesoscale solvophobic aggregates. Increasing local dynamic heterogeneity correlates with an increase in the strength of the slow, aggregate dielectric relaxation and a decrease in the strength of the slow, aggregate mechanical relaxation. Accordingly, increasing local dynamic heterogeneity, brought about by change in temperature and/or cation/anion chemical structure, correlates with an increase in the static dielectric permittivities and a decrease in the contribution of aggregate dynamics to the zero-shear viscosities. The established correlation provides a new ability to distinguish between the influence of mesoscale aggregate shape/morphology versus local and mesoscale ion dynamics on the transport properties of ionic liquids.
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Affiliation(s)
- Tyler Cosby
- Division of Mathematics and Sciences, University of Tennessee Southern, Pulaski, TN, USA.
| | | | | | - Paul C Trulove
- Department of Chemistry, US Naval Academy, Annapolis, MD, USA.
| | - David P Durkin
- Department of Chemistry, US Naval Academy, Annapolis, MD, USA.
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5
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Yao B, Paluch M, Wojnarowska Z. Effect of bulky anions on the liquid-liquid phase transition in phosphonium ionic liquids: Ambient and high-pressure dielectric studies. Sci Rep 2023; 13:3040. [PMID: 36810358 PMCID: PMC9944924 DOI: 10.1038/s41598-023-29518-8] [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: 07/07/2022] [Accepted: 02/06/2023] [Indexed: 02/23/2023] Open
Abstract
Although the first-order liquid-liquid phase transition (LLT) has been reported to exist in various systems (i.e., phosphorus, silicon, water, triphenyl phosphite, etc.), it is still one of the most challenging problems in the field of physical science. Recently, we found that this phenomenon occurs in the family of trihexyl(tetradecyl)phosphonium [P666,14]+ based ionic liquids (ILs) with different anions (Wojnarowska et al in Nat Commun 13:1342, 2022). To understand the molecular structure-property relationships governing LLT, herein, we examine ion dynamics of two other quaternary phosphonium ILs containing long alkyl chains in cation and anion. We found that IL with the anion containing branched -O-(CH2)5-CH3 side chains does not reveal any signs of LLT, while IL with shorter alkyl chains in the anion brings a hidden LLT, i.e., it overlaps with the liquid-glass transition. Ambient pressure dielectric and viscosity measurements revealed a peculiar behavior of ion dynamics near Tg for IL with hidden LLT. Moreover, high-pressure studies have shown that IL with hidden LLT has relatively strong pressure sensitivity compared to the one without first-order phase transition. At the same time, the former exposes the inflection point indicating the concave-convex character of logτσ(P) dependences.
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Affiliation(s)
- B. Yao
- grid.11866.380000 0001 2259 4135Institute of Physics, University of Silesia, SMCEBI, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
| | - M. Paluch
- grid.11866.380000 0001 2259 4135Institute of Physics, University of Silesia, SMCEBI, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
| | - Z. Wojnarowska
- grid.11866.380000 0001 2259 4135Institute of Physics, University of Silesia, SMCEBI, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
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6
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Ando M, Ohta K, Ishida T, Koido R, Shirota H. Physical Properties and Low-Frequency Polarizability Anisotropy and Dipole Responses of Phosphonium Bis(fluorosulfonyl)amide Ionic Liquids with Pentyl, Ethoxyethyl, or 2-(Ethylthio)ethyl Group. J Phys Chem B 2023; 127:542-556. [PMID: 36602430 DOI: 10.1021/acs.jpcb.2c07466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This study compared the physical properties, e.g., glass transition temperature, melting point, viscosity, density, surface tension, and electrical conductivity, and the low-frequency spectra under 200 cm-1 of three synthesized ionic liquids (ILs), triethylpentylphosphonium bis(fluorosulfonyl)amide ([P2225][NF2]), ethoxyethyltriethylphosphonium bis(fluorosulfonyl)amide ([P222(2O2)][NF2]), and triethyl[2-(ethylthio)ethyl]phosphonium bis(fluorosulfonyl)amide ([P222(2S2)][NF2]), at various temperatures using femtosecond Raman-induced Kerr effect spectroscopy (fs-RIKES) and terahertz time-domain spectroscopy (THz-TDS). The [P222(2S2)][NF2] had the highest viscosity and glass transition temperature, whereas the [P222(2O2)][NF2] had the lowest. Among the three ILs, the [P222(2S2)][NF2] had the highest density and surface tension, and the [P222(2O2)][NF2] had the highest electrical conductivity. The RIKES and THz-TDS spectral line shapes for the three ILs varied significantly. For the [P2225][NF2], molecular dynamics simulations successfully reproduced the line shapes of the experimental spectra and indicated that the RIKES spectrum was mainly due to the cation and cross-term and their rotational motions, whereas the THz-TDS spectrum was mainly due to the anion and its translational motion. This shows that it is desirable to utilize both fs-RIKES and THz-TDS methods to reveal molecular motions at the low-frequency domain. The [P222(2S2)][NF2] had higher frequency peaks and broader bands in the low-frequency spectra via fs-RIKES and THz-TDS than those for the [P2225][NF2] and [P222(2O2)][NF2].
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Affiliation(s)
- Masatoshi Ando
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Kaoru Ohta
- Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Tateki Ishida
- Department of Theoretical and Computational Molecular Science, Institute for Molecular Science and Research Center for Computational Science, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
| | - Ryohei Koido
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Hideaki Shirota
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
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7
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Matsumoto M, Takeuchi K, Inoue Y, Tsunashima K, Yamada H. Molecular Insight into the Ionic Conduction of Quaternary Ammonium and Phosphonium Cation-Based Ionic Liquids Using Dielectric and Spectroscopy Analyses. J Phys Chem B 2022; 126:10490-10499. [PMID: 36417887 DOI: 10.1021/acs.jpcb.2c06110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We analyzed the primary properties of ionic liquids (ILs) comprising quaternary phosphonium cations and bis(trifluoromethylsulfonyl) amide anions and compared them with those of corresponding quaternary-ammonium-cation-based ILs. Broadband dielectric spectroscopy was used to confirm the coupling between the translational and orientational motions of ions, and our results demonstrated that the high ionic conductivity of the phosphonium-based ILs was attributed to their fast rotational dynamics. The differences between ILs with different cations were further evaluated using vibrational (Raman and terahertz) spectroscopy. The Raman spectroscopy data revealed that the cation structure affected the conformation and flexibility (conformational change) of the anion. Furthermore, terahertz spectroscopy allowed us to evaluate the relationship between ion transport and intermolecular interactions between the cation and anion of ILs.
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Affiliation(s)
- Mitsuhiro Matsumoto
- Department of Chemical Engineering, National Institute of Technology, Nara College, 22 Yata-cho, Yamatokoriyama, Nara639-1080, Japan
| | - Kazuki Takeuchi
- Department of Chemical Engineering, National Institute of Technology, Nara College, 22 Yata-cho, Yamatokoriyama, Nara639-1080, Japan
| | - Yohtaro Inoue
- Research Division of Polymer Functional Materials, Osaka Research Institute of Industrial Science and Technology, 2-7-1 Ayumino, Izumi, Osaka594-1157, Japan
| | - Katsuhiko Tsunashima
- Department of Applied Chemistry and Biochemistry, National Institute of Technology, Wakayama College, Gobo, Wakayama644-0023, Japan
| | - Hirohisa Yamada
- Department of Chemical Engineering, National Institute of Technology, Nara College, 22 Yata-cho, Yamatokoriyama, Nara639-1080, Japan
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8
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Hofmann A, Rauber D, Wang TM, Hempelmann R, Kay CWM, Hanemann T. Novel Phosphonium-Based Ionic Liquid Electrolytes for Battery Applications. Molecules 2022; 27:molecules27154729. [PMID: 35897904 PMCID: PMC9329924 DOI: 10.3390/molecules27154729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/21/2022] [Accepted: 07/21/2022] [Indexed: 02/04/2023] Open
Abstract
In this study, we address the fundamental question of the physicochemical and electrochemical properties of phosphonium-based ionic liquids containing the counter-ions bis(trifluoromethanesulfonyl)imide ([TFSI]−) and bis(fluorosulfonyl)imide ([FSI]−). To clarify these structure–property as well as structure–activity relationships, trimethyl-based alkyl- and ether-containing phosphonium ILs were systematically synthesized, and their properties, namely density, flow characteristics, alkali metal compatibility, oxidative stability, aluminum corrosivity as well as their use in Li-ion cells were examined comprehensively. The variable moiety on the phosphonium cation exhibited a chain length of four and five, respectively. The properties were discussed as a function of the side chain, counter-ion and salt addition ([Li][TFSI] or [Li][FSI]). High stability coupled with good flow characteristics were found for the phosphonium IL [P1114][TFSI] and the mixture [P1114][TFSI] + [Li][TFSI], respectively.
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Affiliation(s)
- Andreas Hofmann
- Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany; (T.-M.W.); (T.H.)
- Correspondence: ; Tel.: +49-721-608-25920
| | - Daniel Rauber
- Department of Chemistry, Saarland University, Campus B2.2, 66123 Saarbrücken, Germany; (D.R.); (R.H.); (C.W.M.K.)
| | - Tzu-Ming Wang
- Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany; (T.-M.W.); (T.H.)
| | - Rolf Hempelmann
- Department of Chemistry, Saarland University, Campus B2.2, 66123 Saarbrücken, Germany; (D.R.); (R.H.); (C.W.M.K.)
| | - Christopher W. M. Kay
- Department of Chemistry, Saarland University, Campus B2.2, 66123 Saarbrücken, Germany; (D.R.); (R.H.); (C.W.M.K.)
- London Centre for Nanotechnology, Bloomsbury Campus, University College London, 17-19 Gordon Street, London WC1H 0AH, UK
| | - Thomas Hanemann
- Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany; (T.-M.W.); (T.H.)
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 102, D-79110 Freiburg, Germany
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9
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Dielectric Study of Tetraalkylammonium and Tetraalkylphosphonium Levulinate Ionic Liquids. Int J Mol Sci 2022; 23:ijms23105642. [PMID: 35628452 PMCID: PMC9145921 DOI: 10.3390/ijms23105642] [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: 04/18/2022] [Revised: 05/09/2022] [Accepted: 05/14/2022] [Indexed: 11/17/2022] Open
Abstract
Broadband dielectric spectroscopy in a broad temperature range was employed to study ionic conductivity and dynamics in tetraalkylammonium- and tetraalkylphosphonium-based ionic liquids (ILs) having levulinate as a common anion. Combining data for ionic conductivity with data obtained for viscosity in a Walden plot, we show that ionic conductivity is controlled by viscosity while a strong association of ions takes place. Higher values for ionic conductivities in a broad temperature range were found for the tetraalkylphosphonium-based IL compared to its ammonium homolog in accordance with its lower viscosity. Levulinate used in the present study as anion was found to interact and associate stronger with the cations forming ion-pairs or other complexes compared to the NTf2 anion studied in literature. In order to analyze dielectric data, different fitting approaches were employed. The original random barrier model cannot well describe the conductivity especially at the higher frequencies region. In electric modulus representation, two overlapping mechanisms contribute to the broad low frequencies peak. The slower process is related to the conduction mechanism and the faster to the main polarization process of the complex dielectric permittivity representation. The correlation of the characteristic time scales of the previous relaxation processes was discussed in terms of ionic interactions.
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10
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Becher M, Lichtinger A, Minikejew R, Vogel M, Rössler EA. NMR Relaxometry Accessing the Relaxation Spectrum in Molecular Glass Formers. Int J Mol Sci 2022; 23:ijms23095118. [PMID: 35563506 PMCID: PMC9105706 DOI: 10.3390/ijms23095118] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 12/10/2022] Open
Abstract
It is a longstanding question whether universality or specificity characterize the molecular dynamics underlying the glass transition of liquids. In particular, there is an ongoing debate to what degree the shape of dynamical susceptibilities is common to various molecular glass formers. Traditionally, results from dielectric spectroscopy and light scattering have dominated the discussion. Here, we show that nuclear magnetic resonance (NMR), primarily field-cycling relaxometry, has evolved into a valuable method, which provides access to both translational and rotational motions, depending on the probe nucleus. A comparison of 1H NMR results indicates that translation is more retarded with respect to rotation for liquids with fully established hydrogen-bond networks; however, the effect is not related to the slow Debye process of, for example, monohydroxy alcohols. As for the reorientation dynamics, the NMR susceptibilities of the structural (α) relaxation usually resemble those of light scattering, while the dielectric spectra of especially polar liquids have a different broadening, likely due to contributions from cross correlations between different molecules. Moreover, NMR relaxometry confirms that the excess wing on the high-frequency flank of the α-process is a generic relaxation feature of liquids approaching the glass transition. However, the relevance of this feature generally differs between various methods, possibly because of their different sensitivities to small-amplitude motions. As a major advantage, NMR is isotope specific; hence, it enables selective studies on a particular molecular entity or a particular component of a liquid mixture. Exploiting these possibilities, we show that the characteristic Cole-Davidson shape of the α-relaxation is retained in various ionic liquids and salt solutions, but the width parameter may differ for the components. In contrast, the low-frequency flank of the α-relaxation can be notably broadened for liquids in nanoscopic confinements. This effect also occurs in liquid mixtures with a prominent dynamical disparity in their components.
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Affiliation(s)
- Manuel Becher
- Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany; (M.B.); (A.L.); (R.M.)
| | - Anne Lichtinger
- Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany; (M.B.); (A.L.); (R.M.)
| | - Rafael Minikejew
- Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany; (M.B.); (A.L.); (R.M.)
| | - Michael Vogel
- Institut für Physik Kondensierter Materie, Technische Universität Darmstadt, 64289 Darmstadt, Germany;
| | - Ernst A. Rössler
- Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany; (M.B.); (A.L.); (R.M.)
- Correspondence:
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11
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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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12
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Jing BB, Mata P, Zhao Q, Evans CM. Effects of crosslinking density and Lewis acidic sites on conductivity and viscoelasticity of dynamic network electrolytes. JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1002/pol.20210207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Brian B. Jing
- Department of Materials Science and Engineering University of Illinois at Urbana‐Champaign Illinois USA
- Frederick Seitz Materials Research Laboratory University of Illinois at Urbana‐Champaign Illinois USA
- Beckman Institute of Science and Technology University of Illinois at Urbana‐Champaign Illinois USA
| | - Patricia Mata
- Department of Chemical and Biomolecular Engineering University of Illinois at Urbana‐Champaign Illinois USA
- Frederick Seitz Materials Research Laboratory University of Illinois at Urbana‐Champaign Illinois USA
| | - Qiujie Zhao
- Department of Materials Science and Engineering University of Illinois at Urbana‐Champaign Illinois USA
- Frederick Seitz Materials Research Laboratory University of Illinois at Urbana‐Champaign Illinois USA
| | - Christopher M. Evans
- Department of Materials Science and Engineering University of Illinois at Urbana‐Champaign Illinois USA
- Frederick Seitz Materials Research Laboratory University of Illinois at Urbana‐Champaign Illinois USA
- Beckman Institute of Science and Technology University of Illinois at Urbana‐Champaign Illinois USA
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13
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Haddad B, Kachroudi A, Turky G, Belarbi EH, Lamouri A, Villemin D, Rahmouni M, Sylvestre A. The interplay between molecular structure and dielectric propertiesin ionic liquids: A comparative study. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114674] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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14
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Pabst F, Wojnarowska Z, Paluch M, Blochowicz T. On the temperature and pressure dependence of dielectric relaxation processes in ionic liquids. Phys Chem Chem Phys 2021; 23:14260-14275. [PMID: 34159979 DOI: 10.1039/d1cp01636a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular dynamics of ionic liquids in an electric field can be decomposed into contributions from translational motions of ions, rotational motions of permanent dipoles and - in the case of ions equipped with long alkyl-chains - motions of ionic aggregates. The discrimination of these contributions in the dielectric spectrum is quite involved, resulting in numerous controversies in the literature. Here, we use dielectric spectroscopy at ambient and elevated pressures of up to 550 MPa to monitor the changes of the observed processes in five supercooled ionic liquids with octyl-chains independent of pressure and temperature. In most of the ionic liquids under investigation two dynamical processes are observed, one of them is identified as the ion hopping process, which we describe by the MIGRATION model. It turns out that this process is closely connected to the glass transition step as measured by differential scanning calorimetry. Concerning the second process, we rule out motions of aggregated ions to be its origin by comparison of our results with X-ray scattering literature data at elevated pressure. Instead, we tentatively ascribe it to dipolar reorientations and show that the dielectric strength of this slow process decreases as a function of increasing relaxation time, i.e. for decreasing temperatures and increasing pressures. We compare this behavior with literature data of other ion conducting systems and discuss its microscopic origin.
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Affiliation(s)
- Florian Pabst
- TU Darmstadt, Institut für Physik kondensierter Materie, 64289 Darmstadt, Germany.
| | - Zaneta Wojnarowska
- Institute of Physics, University of Silesia in Katowice, SMCEBI, 75 Pulku Piechoty 1A, Chorzow 41-500, Poland
| | - Marian Paluch
- Institute of Physics, University of Silesia in Katowice, SMCEBI, 75 Pulku Piechoty 1A, Chorzow 41-500, Poland
| | - Thomas Blochowicz
- TU Darmstadt, Institut für Physik kondensierter Materie, 64289 Darmstadt, Germany.
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15
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Musiał M, Cheng S, Wojnarowska Z, Yao B, Jurkiewicz K, Paluch M. Thorough studies of tricyanomethanide-based ionic liquids - the influence of alkyl chain length of the cation. SOFT MATTER 2020; 16:9479-9487. [PMID: 32955538 DOI: 10.1039/d0sm01433h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The glassy, supercooled, and normal liquid states of the 1-alkyl-3-methylimidazolium tricyanomethanide series [CnC1im][TCM] (n = 2, 4, 6, 8, and 16) were investigated by dielectric and mechanical (rheological) experiments supplemented by X-ray diffraction. The conductivity relaxation was found to be accompanied by a pronounced secondary relaxation. However, based on ambient and high-pressure results as well as the coupling model, we assumed that the latter one can not be classified as Johari-Goldstein relaxation. Moreover, the studies on the nanoscale organization of ionic liquids indicated that 1-alkyl-3-methylimidazolium tricyanomethanide ILs begin to form nanoscale aggregates when the alkyl chain of the cation has six carbon atoms.
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Affiliation(s)
- Małgorzata Musiał
- Institute of Physics, University of Silesia in Katowice, Silesian Center for Education and Interdisciplinary Research, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland.
| | - Shinian Cheng
- Institute of Physics, University of Silesia in Katowice, Silesian Center for Education and Interdisciplinary Research, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland.
| | - Zaneta Wojnarowska
- Institute of Physics, University of Silesia in Katowice, Silesian Center for Education and Interdisciplinary Research, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland.
| | - Beibei Yao
- Institute of Physics, University of Silesia in Katowice, Silesian Center for Education and Interdisciplinary Research, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland.
| | - Karolina Jurkiewicz
- Institute of Physics, University of Silesia in Katowice, Silesian Center for Education and Interdisciplinary Research, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland.
| | - Marian Paluch
- Institute of Physics, University of Silesia in Katowice, Silesian Center for Education and Interdisciplinary Research, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland.
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16
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Steinrücken E, Becher M, Vogel M. On the molecular mechanisms of α and β relaxations in ionic liquids. J Chem Phys 2020; 153:104507. [DOI: 10.1063/5.0019271] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Elisa Steinrücken
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Manuel Becher
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Michael Vogel
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
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17
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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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18
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Becher M, Steinrücken E, Vogel M. On the relation between reorientation and diffusion in glass-forming ionic liquids with micro-heterogeneous structures. J Chem Phys 2019; 151:194503. [DOI: 10.1063/1.5128420] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Manuel Becher
- Institut für Festkörperphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Elisa Steinrücken
- Institut für Festkörperphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Michael Vogel
- Institut für Festkörperphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
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19
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Cosby T, Kapoor U, Shah JK, Sangoro J. Mesoscale Organization and Dynamics in Binary Ionic Liquid Mixtures. J Phys Chem Lett 2019; 10:6274-6280. [PMID: 31560210 DOI: 10.1021/acs.jpclett.9b02478] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The impact of mesoscale organization on dynamics and ion transport in binary ionic liquid mixtures is investigated by broad-band dielectric spectroscopy, dynamic-mechanical spectroscopy, X-ray scattering, and molecular dynamics simulations. The mixtures are found to form distinct liquids with macroscopic properties that significantly deviate from weighted contributions of the neat components. For instance, it is shown that the mesoscale morphologies in ionic liquids can be tuned by mixing to enhance the static dielectric permittivity of the resulting liquid by as high as 100% relative to the neat ionic liquid components. This enhancement is attributed to the intricate role of interfacial dynamics associated with the changes in the mesoscopic aggregate morphologies in these systems. These results demonstrate the potential to design the physicochemical properties of ionic liquids through control of solvophobic aggregation.
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Affiliation(s)
- Tyler Cosby
- Department of Chemical and Biomolecular Engineering , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | - Utkarsh Kapoor
- School of Chemical Engineering , Oklahoma State University , Stillwater , Oklahoma 74078 , United States
| | - Jindal K Shah
- School of Chemical Engineering , Oklahoma State University , Stillwater , Oklahoma 74078 , United States
| | - Joshua Sangoro
- Department of Chemical and Biomolecular Engineering , University of Tennessee , Knoxville , Tennessee 37996 , United States
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20
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Samet M, Kallel A, Kallel-Elloumi A, Drockenmuller E, Serghei A. Exchange Process in the Dielectric Loss of Molecular and Macromolecular Ionic Conductors in the Interfacial Layers Formed by Electrode Polarization Effects. J Phys Chem B 2019; 123:8532-8542. [PMID: 31566972 DOI: 10.1021/acs.jpcb.9b05837] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Here we report a first analytical approach to determine the spectral dependence of the complex permittivity function of molecular and macromolecular ionic conductors in the interfacial layers formed by electrode polarization effects. We show that a previous model of electrode polarization effects that was successfully applied for describing the dielectric behavior of ionic liquids ( Serghei, A.; Tress, M.; Sangoro, J. R.; Kremer, F. Electrode polarization and charge transport at solid interfaces. Phys. Rev. B 2009 , 80 , 184301 ) can be now generalized and applied for polymer/ionic liquid blends as well as for poly(ionic liquid)s. The determined dielectric function of the interfacial layers reveals a dramatic change in the charge transport process manifested by a large decrease in conductivity. Our approach brings the first evidence for a relaxation peak detected in the dielectric loss of the interfaces, which is attributed to an exchange process between the interface and the bulk. This study gives new insights into the mechanism of charge transport at interfaces and could thus contribute to a better correlation between the dielectric properties of ion conducting materials and their electrochemical behavior at interfaces.
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Affiliation(s)
- M Samet
- Univ Lyon, Université Lyon 1 , CNRS, Ingénierie des Matériaux Polymères, UMR 5223 , F-69003 Lyon , France.,Faculté des Sciences de Sfax , Laboratoire des Matériaux Composites Céramiques et Polymères , 3018 Sfax , Tunisia
| | - A Kallel
- Faculté des Sciences de Sfax , Laboratoire des Matériaux Composites Céramiques et Polymères , 3018 Sfax , Tunisia
| | - A Kallel-Elloumi
- Univ Lyon, Université Lyon 1 , CNRS, Ingénierie des Matériaux Polymères, UMR 5223 , F-69003 Lyon , France
| | - E Drockenmuller
- Univ Lyon, Université Lyon 1 , CNRS, Ingénierie des Matériaux Polymères, UMR 5223 , F-69003 Lyon , France
| | - A Serghei
- Univ Lyon, Université Lyon 1 , CNRS, Ingénierie des Matériaux Polymères, UMR 5223 , F-69003 Lyon , France
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21
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Rahman A, Rahman MM, Mollah MYA, Susan MABH. Ultraslow Relaxation in Aprotic Double Salt Ionic Liquids. J Phys Chem B 2019; 123:5577-5587. [PMID: 31184890 DOI: 10.1021/acs.jpcb.9b03964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A mixture of two pure ionic liquids (ILs) or double salt ILs (DSILs) can push the limits of ILs in terms of unraveling their unique physicochemical properties and potential in clean technology. While the correlated ion dynamics and heterogeneity in the bulk of pure ILs have been reported, such a phenomenon at longer timescales in DSILs has never been elucidated. Here, a combination of temperature-dependent polarized dynamic light scattering and rheological measurements has been employed to reveal the presence of structural and ultraslow relaxation in three DSILs, each containing a 1-ethyl-3-methylimidazolium cation and two different anions. The slow relaxation caused by Brownian diffusion of cluster-like arrangements occurs at a timescale of a few to several hundred milliseconds; both the relaxation processes, nevertheless, are Arrhenius in nature. Notably, slow relaxation in the DSILs is much different compared to that in the pure ILs. The decay of intensity correlation functions (ICFs) and average hydrodynamic correlation length of the clusters and their response to temperature markedly vary with the nature of the two anions present in the DSILs. Stretched exponential analyses of the ICFs disclose the cluster-to-cluster transfer of ionic species as well as percolation dynamics among clusters. The identity of anions also governs whether the DSILs follow or violate the Stokes-Einstein relationship or not.
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Affiliation(s)
- Adhip Rahman
- Material Chemistry Research Laboratory, Department of Chemistry , University of Dhaka , Dhaka 1000 , Bangladesh
| | - M Muhibur Rahman
- Material Chemistry Research Laboratory, Department of Chemistry , University of Dhaka , Dhaka 1000 , Bangladesh
| | | | - Md Abu Bin Hasan Susan
- Material Chemistry Research Laboratory, Department of Chemistry , University of Dhaka , Dhaka 1000 , Bangladesh
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22
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Heres M, Cosby T, Mapesa EU, Liu H, Berdzinski S, Strehmel V, Dadmun M, Paddison SJ, Sangoro J. Ion Transport in Glassy Polymerized Ionic Liquids: Unraveling the Impact of the Molecular Structure. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01273] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
| | | | | | | | - Stefan Berdzinski
- Department of Chemistry and Institute for Coatings and Surface Chemistry, Hochschule Niederrhein University of Applied Sciences, D-47798 Krefeld, Germany
| | - Veronika Strehmel
- Department of Chemistry and Institute for Coatings and Surface Chemistry, Hochschule Niederrhein University of Applied Sciences, D-47798 Krefeld, Germany
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23
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Chen F, Kerr R, Forsyth M. Cation effect on small phosphonium based ionic liquid electrolytes with high concentrations of lithium salt. J Chem Phys 2018; 148:193813. [PMID: 30307212 DOI: 10.1063/1.5016460] [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
Ionic liquid electrolytes with high alkali salt concentrations have displayed some excellent electrochemical properties, thus opening up the field for further improvements to liquid electrolytes for lithium or sodium batteries. Fundamental computational investigations into these high concentration systems are required in order to gain a better understanding of these systems, yet they remain lacking. Small phosphonium-based ionic liquids with high concentrations of alkali metal ions have recently shown many promising results in experimental studies, thereby prompting us to conduct further theoretical exploration of these materials. Here, we conducted a molecular dynamics simulation on four small phosphonium-based ionic liquids with 50 mol. % LiFSI salt, focusing on the effect of cation structure on local structuring and ion diffusional and rotational dynamics-which are closely related to the electrochemical properties of these materials.
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Affiliation(s)
- Fangfang Chen
- Institute for Frontier Materials, Deakin University, Burwood Campus, Burwood, VIC 3125, Australia
| | - Robert Kerr
- Institute for Frontier Materials, Deakin University, Burwood Campus, Burwood, VIC 3125, Australia
| | - Maria Forsyth
- Institute for Frontier Materials, Deakin University, Burwood Campus, Burwood, VIC 3125, Australia
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24
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Cosby T, Vicars Z, Heres M, Tsunashima K, Sangoro J. Dynamic and structural evidence of mesoscopic aggregation in phosphonium ionic liquids. J Chem Phys 2018; 148:193815. [DOI: 10.1063/1.5009765] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- T. Cosby
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Z. Vicars
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - M. Heres
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - K. Tsunashima
- Department of Applied Chemistry and Biochemistry, National Institute of Technology, Wakayama College, Wakayama 644-0023, Japan
| | - J. Sangoro
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
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25
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Cosby T, Vicars Z, Mapesa EU, Tsunashima K, Sangoro J. Charge transport and dipolar relaxations in phosphonium-based ionic liquids. J Chem Phys 2017; 147:234504. [DOI: 10.1063/1.5011190] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Tyler Cosby
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Zachariah Vicars
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Emmanuel Urandu Mapesa
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Katsuhiko Tsunashima
- Department of Applied Chemistry and Biochemistry, National Institute of Technology, Wakayama College, 77 Noshima, Nada-cho, Gobo, Wakayama 644-0023, Japan
| | - Joshua Sangoro
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
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26
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Cosby T, Vicars Z, Wang Y, Sangoro J. Dynamic-Mechanical and Dielectric Evidence of Long-Lived Mesoscale Organization in Ionic Liquids. J Phys Chem Lett 2017; 8:3544-3548. [PMID: 28715220 DOI: 10.1021/acs.jpclett.7b01516] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Experimental evidence of the dynamics of mesoscopic structure in room-temperature ionic liquids-a feature expected to correlate with many physicochemical properties of these materials-remains limited. Here, we report the observation of slow, sub-α relaxations corresponding to dynamics of nanoscale hydrophobic aggregates in a systematic series of 1-alkyl-3-methylimidazolium-based ionic liquids from detailed analysis of dynamic-mechanical and broad-band dielectric spectra. The emergence of the sub-α relaxations correlates with increases in the zero-shear viscosity and static dielectric permittivity, constituting direct evidence of the influence of mesoscale aggregation on the physicochemical properties of ionic liquids.
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Affiliation(s)
- Tyler Cosby
- Department of Chemical and Biomolecular Engineering, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Zachariah Vicars
- Department of Chemical and Biomolecular Engineering, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Yangyang Wang
- Center for Nanophase Materials Science, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Joshua Sangoro
- Department of Chemical and Biomolecular Engineering, University of Tennessee , Knoxville, Tennessee 37996, United States
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27
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Ghatee MH, Bahrami M. Emergence of innovative properties by replacement of nitrogen atom with phosphorus atom in quaternary ammonium ionic liquids: Insights from ab initio calculations and MD simulations. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2017.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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28
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Lima TA, Paschoal VH, Faria LFO, Ribeiro MCC, Giles C. Comparing two tetraalkylammonium ionic liquids. I. Liquid phase structure. J Chem Phys 2016; 144:224504. [DOI: 10.1063/1.4953414] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Thamires A. Lima
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP, Brazil
| | - Vitor H. Paschoal
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP, Brazil
| | - Luiz F. O. Faria
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP, Brazil
| | - Mauro C. C. Ribeiro
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP, Brazil
| | - Carlos Giles
- Departamento de Física da Matéria Condensada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas, SP, Brazil
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29
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Patro LN, Burghaus O, Roling B. Anomalous Wien Effects in Supercooled Ionic Liquids. PHYSICAL REVIEW LETTERS 2016; 116:185901. [PMID: 27203333 DOI: 10.1103/physrevlett.116.185901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Indexed: 06/05/2023]
Abstract
We have measured conductivity spectra of several supercooled monocationic and dicationic ionic liquids in the nonlinear regime by applying ac electric fields with large amplitudes up to about 180 kV/cm. Thereby, higher harmonic ac currents up to the 7th order were detected. Our results point to the existence of anomalous Wien effects in supercooled ionic liquids. Most ionic liquids studied here exhibit a conductivity-viscosity relation, which is close to the predictions of the Nernst-Einstein and Stokes-Einstein equations, as observed for classical strong electrolytes like KCl. These "strong" ionic liquids show a much stronger nonlinearity of the conductivity than classical strong electrolytes. On the other hand, the conductivity-viscosity relation of the ionic liquid [P_{6,6,6,14}][Cl] points to ion association effects. This "weak" ionic liquid shows a strength of the nonlinear effect, which is comparable to classical weak electrolytes. However, the nonlinearity increases quadratically with the field. We suggest that a theory for explaining these anomalies will have to go beyond the level of Coulomb lattice gas models.
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Affiliation(s)
- L N Patro
- Department of Chemistry, Philipps University of Marburg, Marburg, 35032, Germany
| | - O Burghaus
- Department of Chemistry, Philipps University of Marburg, Marburg, 35032, Germany
| | - B Roling
- Department of Chemistry, Philipps University of Marburg, Marburg, 35032, Germany
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30
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Griffin PJ, Wang Y, Holt AP, Sokolov AP. Communication: Influence of nanophase segregation on ion transport in room temperature ionic liquids. J Chem Phys 2016; 144:151104. [DOI: 10.1063/1.4947552] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Affiliation(s)
- Philip J. Griffin
- Department of Material Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Yangyang Wang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Adam P. Holt
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Alexei P. Sokolov
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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31
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Hettige JJ, Araque JC, Kashyap HK, Margulis CJ. Communication: Nanoscale structure of tetradecyltrihexylphosphonium based ionic liquids. J Chem Phys 2016; 144:121102. [DOI: 10.1063/1.4944678] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Juan C. Araque
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA
| | - Hemant K. Kashyap
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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Womble CT, Coates GW, Matyjaszewski K, Noonan KJT. Tetrakis(dialkylamino)phosphonium Polyelectrolytes Prepared by Reversible Addition-Fragmentation Chain Transfer Polymerization. ACS Macro Lett 2016; 5:253-257. [PMID: 35614688 DOI: 10.1021/acsmacrolett.5b00910] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A tetrakis(dialkylamino)phosphonium cation ([P(NR2)4]+) was appended to a styrenic monomer and explored in reversible addition-fragmentation chain transfer polymerization (RAFT) to conduct random copolymerizations of the cationic monomer with styrene. Well-defined polyelectrolytes with molecular weights up to ∼30 100 and dispersities between ∼1.2 and 1.4 were obtained. Up to 18.9 mol % of the ionic monomer could be incorporated into the polymer with hexafluorophosphate or bis(trifluoromethane)sulfonimide acting as the counterion during polymerization. Differential scanning calorimetry of the hexafluorophosphate polymers revealed glass transition temperatures higher than polystyrene likely due to interactions between the anion and the polymer. Thermogravimetric analysis indicated these materials have high thermal stability with decomposition temperatures approaching 400 °C.
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Affiliation(s)
- C. Tyler Womble
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213-2617, United States
| | - Geoffrey W. Coates
- Department
of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, United States
| | - Krzysztof Matyjaszewski
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213-2617, United States
| | - Kevin J. T. Noonan
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213-2617, United States
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Capitani F, Gatto S, Postorino P, Palumbo O, Trequattrini F, Deutsch M, Brubach JB, Roy P, Paolone A. The Complex Dance of the Two Conformers of Bis(trifluoromethanesulfonyl)imide as a Function of Pressure and Temperature. J Phys Chem B 2016; 120:1312-8. [DOI: 10.1021/acs.jpcb.5b12537] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- F. Capitani
- Dipartimento di
Fisica, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy
- Synchrotron SOLEIL, 91192 Gif Sur Yvette, France
| | - S. Gatto
- CNR-ISC, U.O.S. La Sapienza, Piazzale A. Moro 5, 00185 Roma, Italy
| | - P. Postorino
- Dipartimento di
Fisica, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - O. Palumbo
- CNR-ISC, U.O.S. La Sapienza, Piazzale A. Moro 5, 00185 Roma, Italy
| | - F. Trequattrini
- Dipartimento di
Fisica, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy
- CNR-ISC, U.O.S. La Sapienza, Piazzale A. Moro 5, 00185 Roma, Italy
| | - M. Deutsch
- Synchrotron SOLEIL, 91192 Gif Sur Yvette, France
| | | | - P. Roy
- Synchrotron SOLEIL, 91192 Gif Sur Yvette, France
| | - A. Paolone
- CNR-ISC, U.O.S. La Sapienza, Piazzale A. Moro 5, 00185 Roma, Italy
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