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Rams-Baron M, Błażytko A, Książek M, Kusz J, Paluch M. Internal Secondary Relaxation as a Dielectric Probe of Molecular Surroundings. J Phys Chem Lett 2024; 15:2595-2600. [PMID: 38416777 PMCID: PMC10926159 DOI: 10.1021/acs.jpclett.4c00128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2024]
Abstract
We investigated the secondary relaxation behavior in rotor molecules in a glassy and crystalline state by using the dielectric method. Without changing the molecular source of secondary relaxation, only by modifying the environment around the rotating unit we observed notable variations in spectral parameters. Our results show that internal rotation, like a probe, can sample the immediate surroundings with high sensitivity to molecular-level changes that impact the rotation parameters. Our research offers a new perspective on the dielectric behavior of internal secondary relaxations and challenges the paradigm of their irrelevant nature.
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Affiliation(s)
- Marzena Rams-Baron
- August Chelkowski Institute of Physics, University of Silesia in Katowice, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - Alfred Błażytko
- August Chelkowski Institute of Physics, University of Silesia in Katowice, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - Maria Książek
- August Chelkowski Institute of Physics, University of Silesia in Katowice, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - Joachim Kusz
- August Chelkowski Institute of Physics, University of Silesia in Katowice, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - Marian Paluch
- August Chelkowski Institute of Physics, University of Silesia in Katowice, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
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Stachurski CD, Davis JH, Cosby T, Crowley ME, Larm NE, Ballentine MG, O’Brien RA, Zeller M, Salter EA, Wierzbicki A, Trulove PC, Durkin DP. Physical and Electrochemical Analysis of N-Alkylpyrrolidinium-Substituted Boronium Ionic Liquids. Inorg Chem 2023; 62:18280-18289. [PMID: 37870915 PMCID: PMC10630938 DOI: 10.1021/acs.inorgchem.3c02971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Indexed: 10/24/2023]
Abstract
In this work, a series of novel boronium-bis(trifluoromethylsulfonyl)imide [TFSI-] ionic liquids (IL) are introduced and investigated. The boronium cations were designed with specific structural motifs that delivered improved electrochemical and physical properties, as evaluated through cyclic voltammetry, broadband dielectric spectroscopy, densitometry, thermogravimetric analysis, and differential scanning calorimetry. Boronium cations, which were appended with N-alkylpyrrolidinium substituents, exhibited superior physicochemical properties, including high conductivity, low viscosity, and electrochemical windows surpassing 6 V. Remarkably, the boronium ionic liquid functionalized with both an ethyl-substituted pyrrolidinium and trimethylamine, [(1-e-pyrr)N111BH2][TFSI], exhibited a 6.3 V window, surpassing previously published boronium-, pyrrolidinium-, and imidazolium-based IL electrolytes. Favorable physical properties and straightforward tunability make boronium ionic liquids promising candidates to replace conventional organic electrolytes for electrochemical applications requiring high voltages.
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Affiliation(s)
| | - James H. Davis
- Department
of Chemistry, University of South Alabama, Mobile, Alabama36688, United States
| | - Tyler Cosby
- School
of Mathematics and Sciences, University
of Tennessee Southern, Pulaski, Tennessee38478, United States
| | - Margaret E. Crowley
- Department
of Chemistry, University of South Alabama, Mobile, Alabama36688, United States
| | - Nathaniel E. Larm
- Department
of Chemistry, U.S. Naval Academy, Annapolis, Maryland21402, United States
| | - Mollie G. Ballentine
- Department
of Chemistry, University of South Alabama, Mobile, Alabama36688, United States
| | - Richard A. O’Brien
- Department
of Chemistry, University of South Alabama, Mobile, Alabama36688, United States
| | - Matthias Zeller
- Department
of Chemistry, Purdue University, West Lafayette, Indiana47907, United States
| | - E. Alan Salter
- Department
of Chemistry, University of South Alabama, Mobile, Alabama36688, United States
| | - Andrzej Wierzbicki
- Department
of Chemistry, University of South Alabama, Mobile, Alabama36688, United States
| | - Paul C. Trulove
- Department
of Chemistry, U.S. Naval Academy, Annapolis, Maryland21402, United States
| | - David P. Durkin
- Department
of Chemistry, U.S. Naval Academy, Annapolis, Maryland21402, United States
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Yao B, Paluch M, Dulski M, Quinn C, McLaughlin S, McGrogan A, Swadzba-Kwasny M, Wojnarowska Z. Tailoring Phosphonium Ionic Liquids for a Liquid-Liquid Phase Transition. J Phys Chem Lett 2023; 14:2958-2964. [PMID: 36939303 PMCID: PMC10068824 DOI: 10.1021/acs.jpclett.3c00099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/16/2023] [Indexed: 06/18/2023]
Abstract
The existence of more than one liquid state in a single-component system remains the most intriguing physical phenomenon. Herein, we explore the effect of cation self-assembly on ion dynamics in the vicinity of liquid-liquid and liquid-glass transition of tetraalkyl phosphonium ([Pmmm,n]+, m = 4, 6; n = 2-14) ionic liquids. We found that nonpolar local domains formed by 14-carbon alkyl chains are crucial in obtaining two supercooled states of different dynamics within a single ionic liquid. Although the nano-ordering, confirmed by Raman spectroscopy, still occurs for shorter alkyl chains (m = 6, n < 14), it does not bring calorimetric evidence of LLT. Instead, it results in peculiar behavior of ion dynamics near the liquid-glass transition and 20-times smaller size of the dynamic heterogeneity compared to imidazolium ionic liquids. These results represent a crucial step toward understanding the nature of the LLT phenomenon and offer insight into the design of efficient electrolytes based on ionic liquids revealing self-assembly behavior.
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Affiliation(s)
- Beibei Yao
- Faculty
of Science and Technology, Institute of Physics, University of Silesia in Katowice, 75 Pułku Piechoty 1A, 41−500 Chorzów, Poland
| | - Marian Paluch
- Faculty
of Science and Technology, Institute of Physics, University of Silesia in Katowice, 75 Pułku Piechoty 1A, 41−500 Chorzów, Poland
| | - Mateusz Dulski
- Faculty
of Science and Technology, Institute of Materials Science, the University of Silesia in Katowice, 75 Pułku Piechoty 1A, 41−500 Chorzów, Poland
| | - Courtney Quinn
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, David Keir Building, Stranmillis
Road, BT9 5AG Belfast, Northern Ireland, U.K.
| | - Shannon McLaughlin
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, David Keir Building, Stranmillis
Road, BT9 5AG Belfast, Northern Ireland, U.K.
| | - Anne McGrogan
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, David Keir Building, Stranmillis
Road, BT9 5AG Belfast, Northern Ireland, U.K.
| | - Malgorzata Swadzba-Kwasny
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, David Keir Building, Stranmillis
Road, BT9 5AG Belfast, Northern Ireland, U.K.
| | - Zaneta Wojnarowska
- Faculty
of Science and Technology, Institute of Physics, University of Silesia in Katowice, 75 Pułku Piechoty 1A, 41−500 Chorzów, Poland
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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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