1
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Jitvisate M. Direct Measurement of the Differential Capacitance of Deep Eutectic Solvents on Platinum and Glassy Carbon Electrodes. J Phys Chem Lett 2024; 15:9637-9643. [PMID: 39282944 PMCID: PMC11440589 DOI: 10.1021/acs.jpclett.4c02428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2024]
Abstract
Differential capacitance is a crucial parameter that connects the experimental observation of electrical double-layer behavior with theoretical models. However, the current number of reported differential capacitance values for deep eutectic solvents remains limited, making it challenging to verify or refute existing models. In this study, we systematically investigate the differential capacitance in deep eutectic solvents using chronoamperometry. By comparing metal and glassy carbon electrodes across various liquid combinations and ion concentrations, we observed a range of distinct capacitance characteristics. While some findings align with the existing mean-field model for ionic liquids, others clearly reflect the influence of electrode materials, with certain cases resisting full explanation by current theoretical models. These results underscore the importance of selecting appropriate electrode materials in experimental studies of such electrolytes and highlight the need for further theoretical advancements in understanding this complex liquid system.
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Affiliation(s)
- Monchai Jitvisate
- School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
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2
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Kahlon NK, Matthewman EL, El Mohamad M, Greaves TL, Weber CC. Small-Angle X-ray Scattering Study of the Amphiphilic Bulk Nanostructure of Tetraalkylammonium Deep Eutectic Solvents. J Phys Chem B 2024. [PMID: 38662201 DOI: 10.1021/acs.jpcb.4c00943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Deep eutectic solvents (DESs) are low-melting mixtures, often prepared from a salt and a molecular hydrogen bond donor. Like ionic liquids, DESs that contain at least one sufficiently amphiphilic component can form bicontinuous nanostructures consisting of polar and nonpolar domains, although this has not been widely explored for many DES combinations. Here, the bulk nanostructures of DESs comprising tetraalkylammonium bromide salts (tetrabutylammonium bromide, tetraoctylammonium bromide, and methyltrioctylammonium bromide) with alkanols and alkanoic acids of systematically varied chain lengths (C2, C6, C8, and C10) as hydrogen bond donors have been studied. Small-angle X-ray scattering techniques were used to identify the relationship between the alkyl chain length and functionality of the hydrogen bond donor on the nature of the amphiphilic nanostructures formed. These findings demonstrated that the amphiphilic nanostructures of the DESs were not affected by the functional group on the hydrogen bond donor, with these nanostructures influenced primarily by both the absolute and relative alkyl chain lengths of the salt and hydrogen bond donor.
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Affiliation(s)
- Navjot K Kahlon
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Emma L Matthewman
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | | | | | - Cameron C Weber
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
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3
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Hayler HJ, Groves TS, Guerrini A, Southam A, Zheng W, Perkin S. The surface force balance: direct measurement of interactions in fluids and soft matter. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:046601. [PMID: 38382100 DOI: 10.1088/1361-6633/ad2b9b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/21/2024] [Indexed: 02/23/2024]
Abstract
Over the last half-century, direct measurements of surface forces have been instrumental in the exploration of a multitude of phenomena in liquid, soft, and biological matter. Measurements of van der Waals interactions, electrostatic interactions, hydrophobic interactions, structural forces, depletion forces, and many other effects have checked and challenged theoretical predictions and motivated new models and understanding. The gold-standard instrument for these measurements is thesurface force balance(SFB), orsurface forces apparatus, where interferometry is used to detect the interaction force and distance between two atomically smooth planes, with 0.1 nm resolution, over separations from about 1 µm down to contact. The measured interaction forcevs.distance gives access to the free energy of interaction across the fluid film; a fundamental quantity whose general form and subtle features reveal the underlying molecular and surface interactions and their variation. Motivated by new challenges in emerging fields of research, such as energy storage, biomaterials, non-equilibrium and driven systems, innovations to the apparatus are now clearing the way for new discoveries. It is now possible to measure interaction forces (and free energies) with control of electric field, surface potential, surface chemistry; to measure time-dependent effects; and to determine structurein situ. Here, we provide an overview the operating principles and capabilities of the SFB with particular focus on the recent developments and future possibilities of this remarkable technique.
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Affiliation(s)
- Hannah J Hayler
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Timothy S Groves
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Aurora Guerrini
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Astrid Southam
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Weichao Zheng
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Susan Perkin
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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4
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Hayler H, Hallett JE, Perkin S. Hydrogen Bond Donors Dictate the Frictional Response in Deep Eutectic Solvents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:5695-5700. [PMID: 38444101 PMCID: PMC10956492 DOI: 10.1021/acs.langmuir.3c03303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 03/07/2024]
Abstract
Deep eutectic solvents (DESs) show promise as boundary lubricants between sliding surfaces, taking advantage of their physical stability, chemical stability, and tunability. Here, we study friction forces across nanofilms of two archetypal DES mixtures: choline chloride + ethylene glycol and choline chloride + glycerol. Using a surface force balance, we control the film thickness (to subnanometer precision) and determine the friction force simultaneously. Measurements are made at different mole fractions of the choline chloride salt and the molecular solvent, allowing us to determine the role of each species in the observed behavior. We find that the nature of the molecular solvent is dominant in determining the lubrication behavior, while the fraction of ChCl is relatively less important. By analyzing the steps in friction and the gradient of friction with load as the layers squeeze away from between the surfaces, we learn various mechanistic aspects of lubrication across the DES nanofilms of relevance to design and optimization of these promising fluids.
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Affiliation(s)
- Hannah
J. Hayler
- Physical
and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, U.K.
| | - James E. Hallett
- Department
of Chemistry, School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights Campus, Reading RG6 6AD, U.K.
| | - Susan Perkin
- Physical
and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, U.K.
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5
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Liang H, Xia X, Liu M, Zou S, Yin T, Li H, Zhang Y, Min C, Bu Y. Competition-Induced Macroscopic Superlubricity of Ionic Liquid Analogues by Hydroxyl Ligands Revealed by in Situ Raman. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:4277-4284. [PMID: 38360538 DOI: 10.1021/acs.langmuir.3c03461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
High load-bearing capacity is one of the crucial indicators for liquid superlubricants to move toward practicality. However, some of the current emerging systems not only have low contact pressures but also are highly susceptible to further degradation due to water adsorption and even superlubricity failure. Herein, a novel choline chloride-based ionic liquid analogues (ILAs) of a superlubricant with triethanolamine (TEOA) as the H-bond donor is reported for the first time; it obtains an ultralow coefficient of friction (0.005) and high load-bearing capacity (360 MPa, more than 2 times that of similar systems) due to adsorption of a small amount of water (<5 wt %) from the air. In situ Raman combined with 1H NMR and FTIR techniques reveals that adsorbed water competes with the hydroxyl group of TEOA for coordination with Cl-, leading to the conversion of some strong H-bonds to weak H-bonds in ILAs; the localized strong H-bonds and weak H-bonds endow the ILAs with high load-bearing capacity and the formation of ultralow shear-resistance sliding interfaces, respectively, under the shear motion. This study proposes a strategy to modulate the interactions between liquid species using adsorbed water from air as a competing ligand, which provides new insights into the design of ILA-based macroscopic liquid superlubricants with a high load-bearing capacity.
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Affiliation(s)
- Hongyu Liang
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Xiaojie Xia
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Manqiang Liu
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Shijing Zou
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Tianqiang Yin
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Hongfei Li
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Yanhu Zhang
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Chunying Min
- School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Yongfeng Bu
- Institute for Energy Research, Jiangsu University, Zhenjiang 212013, China
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6
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Robertson H, Elliott GR, Nelson ARJ, Le Brun AP, Webber GB, Prescott SW, Craig VSJ, Wanless EJ, Willott JD. Underscreening in concentrated electrolytes: re-entrant swelling in polyelectrolyte brushes. Phys Chem Chem Phys 2023; 25:24770-24782. [PMID: 37671535 DOI: 10.1039/d3cp02206d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
Hypersaline environments are ubiquitous in nature and are found in myriad technological processes. Recent empirical studies have revealed a significant discrepancy between predicted and observed screening lengths at high salt concentrations, a phenomenon referred to as underscreening. Herein we investigate underscreening using a cationic polyelectrolyte brush as an exemplar. Poly(2-(methacryloyloxy)ethyl)trimethylammonium (PMETAC) brushes were synthesised and their internal structural changes and swelling response was monitored with neutron reflectometry and spectroscopic ellipsometry. Both techniques revealed a monotonic brush collapse as the concentration of symmetric monovalent electrolyte increased. However, a non-monotonic change in brush thickness was observed in all multivalent electrolytes at higher concentrations, known as re-entrant swelling; indicative of underscreening. For all electrolytes, numerical self-consistent field theory predictions align with experimental studies in the low-to-moderate salt concentration regions. Analysis suggests that the classical theory of electrolytes is insufficient to describe the screening lengths observed at high salt concentrations and that the re-entrant polyelectrolyte brush swelling seen herein is consistent with the so-called regular underscreening phenomenon.
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Affiliation(s)
- Hayden Robertson
- College of Science, Engineering and Environment, University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Gareth R Elliott
- College of Science, Engineering and Environment, University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Andrew R J Nelson
- Australian Centre for Neutron Scattering, ANSTO, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Anton P Le Brun
- Australian Centre for Neutron Scattering, ANSTO, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Grant B Webber
- College of Science, Engineering and Environment, University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Stuart W Prescott
- School of Chemical Engineering, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Vincent S J Craig
- Department of Materials Physics, Research School of Physics, Australian National University, Canberra, ACT 0200, Australia
| | - Erica J Wanless
- College of Science, Engineering and Environment, University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Joshua D Willott
- College of Science, Engineering and Environment, University of Newcastle, Callaghan, NSW 2308, Australia.
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7
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Chatterjee S, Chowdhury T, Bagchi S. Does variation in composition affect dynamics when approaching the eutectic composition? J Chem Phys 2023; 158:114203. [PMID: 36948840 DOI: 10.1063/5.0139153] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
Deep eutectic solvent is a mixture of two or more components, mixed in a certain molar ratio, such that the mixture melts at a temperature lower than individual substances. In this work, we have used a combination of ultrafast vibrational spectroscopy and molecular dynamics simulations to investigate the microscopic structure and dynamics of a deep eutectic solvent (1:2 choline chloride: ethylene glycol) at and around the eutectic composition. In particular, we have compared the spectral diffusion and orientational relaxation dynamics of these systems with varying compositions. Our results show that although the time-averaged solvent structures around a dissolved solute are comparable across compositions, both the solvent fluctuations and solute reorientation dynamics show distinct differences. We show that these subtle changes in solute and solvent dynamics with changing compositions arise from the variations in the fluctuations of the different intercomponent hydrogen bonds.
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Affiliation(s)
- Srijan Chatterjee
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Tubai Chowdhury
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Sayan Bagchi
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
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8
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Freeman JS, Mamme MH, Ustarroz J, Warr GG, Li H, Atkin R. Molecular Resolution Nanostructure and Dynamics of the Deep Eutectic Solvent-Graphite Interface as a Function of Potential. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2204993. [PMID: 36627266 DOI: 10.1002/smll.202204993] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 12/08/2022] [Indexed: 06/17/2023]
Abstract
Interest in deep eutectic solvents (DESs), particularly for electrochemical applications, has boomed in the past decade because they are more versatile than conventional electrolyte solutions and are low cost, renewable, and non-toxic. The molecular scale lateral nanostructures as a function of potential at the solid-liquid interface-critical design parameters for the use of DESs as electrochemical solvents-are yet to be revealed. In this work, in situ amplitude modulated atomic force microscopy complemented by molecular dynamics simulations is used to probe the Stern and near-surface layers of the archetypal and by far most studied DES, 1:2 choline chloride:urea (reline), at the highly orientated pyrolytic graphite surface as a function of potential, to reveal highly ordered lateral nanostructures with unprecedented molecular resolution. This detail allows identification of choline, chloride, and urea in the Stern layer on graphite, and in some cases their orientations. Images obtained after the potential is switched from negative to positive show the dynamics of the Stern layer response, revealing that several minutes are required to reach equilibrium. These results provide valuable insight into the nanostructure and dynamics of DESs at the solid-liquid interface, with implications for the rational design of DESs for interfacial applications.
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Affiliation(s)
- Justin S Freeman
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Mesfin Haile Mamme
- Research Group Electrochemical and Surface Engineering (SURF), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
| | - Jon Ustarroz
- Research Group Electrochemical and Surface Engineering (SURF), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
- Chemistry of Surfaces, Interfaces and Nanomaterials (ChemSIN), Université Libre de Bruxelles, Boulevard du Triomphe 2, Brussels, 1050, Belgium
| | - Gregory G Warr
- School of Chemistry and University of Sydney Nano Institute, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
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9
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Liang H, Yin T, Liu M, Fu C, Xia X, Zou S, Hua X, Fu Y, Bu Y. Unravelling High-Load Superlubricity of Ionic Liquid Analogues by In Situ Raman: Incomplete Hydration Induced by Competitive Exchange of External Water with Crystalline Water. J Phys Chem Lett 2023; 14:453-459. [PMID: 36622949 DOI: 10.1021/acs.jpclett.2c03667] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
A high load-carrying capacity is the key to the practicality of liquid superlubricity, but it is difficult to achieve high load and low friction simultaneously by relying solely on a liquid film. Herein, a choline chloride-based ionic liquid analogue (ILA) macroscale superlubricant is first reported by tuning down strong hydrogen bonding in the ILA via introducing 2-10 wt % water, with a high load of 160 MPa and a low coefficient of friction of 0.006-0.008. In situ Raman reveals that competitive exchange between external water and crystalline water induces weak H-bond-dominated incomplete hydration, conferring a low-shear interface and considerable load-carrying capacity inside the lubricant. It is a hydrodynamic lubrication film rather than a tribochemical/physical adsorption film, allowing it to be applied to friction pairs of various materials. This study unveils the principle of water mediation of high-viscosity ILAs and also provides new insights into the design of practical ILA-based superlubrication materials with high load-carrying capacity.
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Affiliation(s)
- Hongyu Liang
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang212013, China
| | - Tianqiang Yin
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang212013, China
| | - Manqiang Liu
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang212013, China
| | - Caihong Fu
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang212013, China
| | - Xiaojie Xia
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang212013, China
| | - Shijing Zou
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang212013, China
| | - Xijun Hua
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang212013, China
| | - Yonghong Fu
- Institute of Advanced Manufacturing and Modern Equipment Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang212013, China
| | - Yongfeng Bu
- Institute for Energy Research, Jiangsu University, Zhenjiang212013, China
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10
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Intermolecular Interactions of Edaravone in Aqueous Solutions of Ethaline and Glyceline Inferred from Experiments and Quantum Chemistry Computations. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28020629. [PMID: 36677688 PMCID: PMC9863297 DOI: 10.3390/molecules28020629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 12/31/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023]
Abstract
Edaravone, acting as a cerebral protective agent, is administered to treat acute brain infarction. Its poor solubility is addressed here by means of optimizing the composition of the aqueous choline chloride (ChCl)-based eutectic solvents prepared with ethylene glycol (EG) or glycerol (GL) in the three different designed solvents compositions. The slurry method was used for spectroscopic solubility determination in temperatures between 298.15 K and 313.15 K. Measurements confirmed that ethaline (ETA = ChCl:EG = 1:2) and glyceline (GLE = ChCl:GL = 1:2) are very effective solvents for edaravone. The solubility at 298.15 K in the optimal compositions was found to be equal xE = 0.158 (cE = 302.96 mg/mL) and xE = 0.105 (cE = 191.06 mg/mL) for glyceline and ethaline, respectively. In addition, it was documented that wetting of neat eutectic mixtures increases edaravone solubility which is a fortunate circumstance not only from the perspective of a solubility advantage but also addresses high hygroscopicity of eutectic mixtures. The aqueous mixture with 0.6 mole fraction of the optimal composition yielded solubility values at 298.15 K equal to xE = 0.193 (cE = 459.69 mg/mL) and xE = 0.145 (cE = 344.22 mg/mL) for glyceline and ethaline, respectively. Since GLE is a pharmaceutically acceptable solvent, it is possible to consider this as a potential new liquid form of this drug with a tunable dosage. In fact, the recommended amount of edaravone administered to patients can be easily achieved using the studied systems. The observed high solubility is interpreted in terms of intermolecular interactions computed using the Conductor-like Screening Model for Real Solvents (COSMO-RS) approach and corrected for accounting of electron correlation, zero-point vibrational energy and basis set superposition errors. Extensive conformational search allowed for identifying the most probable contacts, the thermodynamic and geometric features of which were collected and discussed. It was documented that edaravone can form stable dimers stabilized via stacking interactions between five-membered heterocyclic rings. In addition, edaravone can act as a hydrogen bond acceptor with all components of the studied systems with the highest affinities to ion pairs of ETA and GLE. Finally, the linear regression model was formulated, which can accurately estimate edaravone solubility utilizing molecular descriptors obtained from COSMO-RS computations. This enables the screening of new eutectic solvents for finding greener replacers of designed solvents. The theoretical analysis of tautomeric equilibria confirmed that keto-isomer edaravone is predominant in the bulk liquid phase of all considered deep eutectic solvents (DES).
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11
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Zhang Y, Klein JM, Akolkar R, Gurkan BE, Maginn EJ. Solvation Structure, Dynamics, and Charge Transfer Kinetics of Cu 2+ and Cu + in Choline Chloride Ethylene Glycol Electrolytes. J Phys Chem B 2022; 126:6493-6499. [PMID: 35976689 DOI: 10.1021/acs.jpcb.2c04798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Experimental measurements and classical molecular dynamics (MD) simulations were carried out to study electrolytes containing CuCl2 and CuCl salts in mixtures of choline chloride (ChCl) and ethylene glycol (EG). The study focused on the concentration of 100 mM of both CuCl2 and CuCl with the ratio of ChCl/EG varied from 1:2, 1:3, 1:4, to 1:5. It was found that the Cu2+ and Cu+ have different solvation environments in their first solvation shell. Cu2+ is coordinated by both Cl- anions and EG molecules, whereas Cu+ is only solvated by EG. However, both Cu2+ and Cu+ show strong interactions with their second solvation shells, which include both Cl- anions and EG molecules. Considering both the first and second solvation shells, the concentrations of Cu2+ and Cu+ that have various coordination numbers in each solution were calculated and were found to correlate qualitatively with the exchange current density trends reported in previous experiments of Cu2+ reduction to Cu+. This finding makes a connection between atomic solvation structure observed in MD simulations and redox reaction kinetics measured in electrochemical experiments, thus revealing the significance of the solvation environment of reduced and oxidized species for electrokinetics in deep eutectic solvents.
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Affiliation(s)
- Yong Zhang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jeffrey M Klein
- Department of Chemical and Biomolecular Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Rohan Akolkar
- Department of Chemical and Biomolecular Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Burcu E Gurkan
- Department of Chemical and Biomolecular Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Edward J Maginn
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
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12
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Self-assembled nanostructure induced in deep eutectic solvents via an amphiphilic hydrogen bond donor. J Colloid Interface Sci 2022; 616:121-128. [DOI: 10.1016/j.jcis.2022.02.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/01/2022] [Accepted: 02/06/2022] [Indexed: 12/19/2022]
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13
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Donato MT, Santos L, Diogo HP, Colaço R, Branco LC, Saramago B. Eutectic systems containing an ionic liquid and PEG200 as lubricants for silicon surfaces: Effect of the mixture’s molar ratio. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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14
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Mudring AV, Hammond O. Ionic Liquids and Deep Eutectics as a Transformative Platform for the Synthesis of Nanomaterials. Chem Commun (Camb) 2022; 58:3865-3892. [DOI: 10.1039/d1cc06543b] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ionic liquids (ILs) are becoming a revolutionary synthesis medium for inorganic nanomaterials, permitting more efficient, safer and environmentally benign preparation of high quality products. A smart combination of ILs and...
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15
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Bulk and interfacial nanostructure and properties in deep eutectic solvents: Current perspectives and future directions. J Colloid Interface Sci 2021; 608:2430-2454. [PMID: 34785053 DOI: 10.1016/j.jcis.2021.10.163] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/25/2022]
Abstract
Deep eutectic solvents (DESs) are a tailorable class of solvents that are rapidly gaining scientific and industrial interest. This is because they are distinct from conventional molecular solvents, inherently tuneable via careful selection of constituents, and possess many attractive properties for applications, including catalysis, chemical extraction, reaction media, novel lubricants, materials chemistry, and electrochemistry. DESs are a class of solvents composed solely of hydrogen bond donors and acceptors with a melting point lower than the individual components and are often fluidic at room temperature. A unique feature of DESs is that they possess distinct bulk liquid and interfacial nanostructure, which results from intra- and inter-molecular interactions, including coulomb forces, hydrogen bonding, van der Waals interactions, electrostatics, dispersion forces, and apolar-polar segregation. This nanostructure manifests as preferential spatial arrangements of the different species, and exists over several length scales, from molecular- to nano- and meso-scales. The physicochemical properties of DESs are dictated by structure-property relationships; however, there is a significant gap in our understanding of the underlying factors which govern their solvent properties. This is a major limitation of DES-based technologies, as nanostructure can significantly influence physical properties and thus potential applications. This perspective provides an overview of the current state of knowledge of DES nanostructure, both in the bulk liquid and at solid interfaces. We provide definitions which clearly distinguish DESs as a unique solvent class, rather than a subset of ILs. An appraisal of recent work provides hints towards trends in structure-property relationships, while also highlighting inconsistencies within the literature suggesting new research directions for the field. It is hoped that this review will provide insight into DES nanostructure, their potential applications, and development of a robust framework for systematic investigation moving forward.
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Aminoguanidine-based deep eutectic solvents as environmentally-friendly and high-performance lubricant additives. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116829] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Elbourne A, Meftahi N, Greaves TL, McConville CF, Bryant G, Bryant SJ, Christofferson AJ. Nanostructure of a deep eutectic solvent at solid interfaces. J Colloid Interface Sci 2021; 591:38-51. [PMID: 33592524 DOI: 10.1016/j.jcis.2021.01.089] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 12/24/2022]
Abstract
HYPOTHESIS Deep eutectic solvents (DESs) are an attractive class of tunable solvents. However, their uptake for relevant applications has been limited due to a lack of detailed information on their structure-property relationships, both in the bulk and at interfaces. The lateral nanostructure of the DES-solid interfaces is likely to be more complex than previously reported and requires detailed, high-resolution investigation. EXPERIMENTS We employ a combination of high-resolution amplitude-modulated atomic force microscopy and molecular dynamics simulations to elucidate the lateral nanostructure of a DES at the solid-liquid interface. Specifically, the lateral and near-surface nanostructure of the DES choline chloride:glycerol is probed at the mica and highly-ordered pyrolytic graphite interfaces. FINDINGS The lateral nanostructure of the DES-solid interface is heterogeneous and well-ordered in both systems. At the mica interface, the DES is strongly ordered via polar interactions. The adsorbed layer has a distinct rhomboidal symmetry with a repeat spacing of ~0.9 nm comprising all DES species. At the highly ordered pyrolytic graphite interface, the adsorbed layer appears distinctly different, forming an apolor-driven row-like structure with a repeat spacing of ~0.6 nm, which largely excludes the chloride ion. The interfacial nanostructure results from a delicate balance of substrate templating, liquid-liquid interactions, species surface affinity, and packing constraints of cations, anions, and molecular components within the DES. For both systems, distinct near-surface nanostructural layering is observed, which becomes more pronounced close to the substrate. The surface nanostructures elucidated here significantly expand our understanding of DES interfacial behavior and will enhance the optimization of DES systems for surface-based applications.
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Affiliation(s)
- Aaron Elbourne
- School of Science, RMIT University, Melbourne, VIC 3000, Australia.
| | - Nastaran Meftahi
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, VIC 3001, Australia
| | - Tamar L Greaves
- School of Science, RMIT University, Melbourne, VIC 3000, Australia
| | - Christopher F McConville
- School of Science, RMIT University, Melbourne, VIC 3000, Australia; Institute for Frontier Materials, Deakin University, Geelong, Victoria 3216, Australia
| | - Gary Bryant
- School of Science, RMIT University, Melbourne, VIC 3000, Australia
| | - Saffron J Bryant
- School of Science, RMIT University, Melbourne, VIC 3000, Australia.
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