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Bachler J, Daidone I, Zanetti-Polzi L, Loerting T. Tuning the low-temperature phase behavior of aqueous ionic liquids. Phys Chem Chem Phys 2024; 26:9741-9753. [PMID: 38470827 DOI: 10.1039/d3cp06101a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
Water's anomalous behavior is often explained using a two-liquid model, where two types of water, high-density liquid (HDL) and low-density liquid (LDL), can be separated via a liquid-liquid phase transition (LLPT) at low temperature. Mixtures of water and the ionic liquid hydrazinium trifluoroacetate were suggested to also show an LLPT but with the advantage that there is no rapid ice crystallization hampering its observation. It remains controversial whether these solutions exhibit an LLPT or are instead associated with complex phase separation phenomena. We here show detailed low-temperature calorimetry and diffraction experiments on aqueous solutions containing hydrazinium trifluoroacetate and other similar ionic liquids, all at a solute mole fraction of x = 0.175. Hydrazinium trifluoroacetate, ammonium trifluoroacetate, ethylammonium trifluoroacetate and hydrazinium pentafluoropropionate all boast exothermic transitions unrelated to crystallization as well as remarkable structural changes upon cooling into the glassy state. We propose a model inspired by micelle formation and decomposition in surfactant solutions, which is complemented by MD simulations and allows rationalizing the rich phase behavior of our mixtures during cooling. The fundamental aspect of the model is the hydrophobic nature of fluorinated anions that enables aggregation, which is reversed upon cooling and culminates in the remarkable exothermic first-order transition observed at low temperature. That is, we assign the first-order transition not to an LLPT but to phase-separations similar to the ones when falling below the Krafft temperature. All other solutions merely show simple vitrification behavior. Still, they exhibit distinct differences in liquid fragility, which is decreased continuously with decreasing hydrophobicity of the anions. This might enable the systematic tuning of ionic liquids with the goal of designing aqueous solutions of specific fragility.
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Affiliation(s)
- Johannes Bachler
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, Innsbruck A-6020, Austria.
| | - Isabella Daidone
- Department of Physical and Chemical Sciences, University of L'Aquila, L'Aquila 67010, Italy
| | | | - Thomas Loerting
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, Innsbruck A-6020, Austria.
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2
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Gallo P, Bachler J, Bove LE, Böhmer R, Camisasca G, Coronas LE, Corti HR, de Almeida Ribeiro I, de Koning M, Franzese G, Fuentes-Landete V, Gainaru C, Loerting T, de Oca JMM, Poole PH, Rovere M, Sciortino F, Tonauer CM, Appignanesi GA. Advances in the study of supercooled water. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:143. [PMID: 34825973 DOI: 10.1140/epje/s10189-021-00139-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/17/2021] [Indexed: 06/13/2023]
Abstract
In this review, we report recent progress in the field of supercooled water. Due to its uniqueness, water presents numerous anomalies with respect to most simple liquids, showing polyamorphism both in the liquid and in the glassy state. We first describe the thermodynamic scenarios hypothesized for the supercooled region and in particular among them the liquid-liquid critical point scenario that has so far received more experimental evidence. We then review the most recent structural indicators, the two-state model picture of water, and the importance of cooperative effects related to the fact that water is a hydrogen-bonded network liquid. We show throughout the review that water's peculiar properties come into play also when water is in solution, confined, and close to biological molecules. Concerning dynamics, upon mild supercooling water behaves as a fragile glass former following the mode coupling theory, and it turns into a strong glass former upon further cooling. Connections between the slow dynamics and the thermodynamics are discussed. The translational relaxation times of density fluctuations show in fact the fragile-to-strong crossover connected to the thermodynamics arising from the existence of two liquids. When considering also rotations, additional crossovers come to play. Mobility-viscosity decoupling is also discussed in supercooled water and aqueous solutions. Finally, the polyamorphism of glassy water is considered through experimental and simulation results both in bulk and in salty aqueous solutions. Grains and grain boundaries are also discussed.
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Affiliation(s)
- Paola Gallo
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, Via della Vasca Navale 84, 00146, Roma, Italy.
| | - Johannes Bachler
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, A-6020, Innsbruck, Austria
| | - Livia E Bove
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 5, 00185, Roma, Italy
- Sorbonne Université, CNRS UMR 7590, IMPMC, 75005, Paris, France
| | - Roland Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221, Dortmund, Germany
| | - Gaia Camisasca
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, Via della Vasca Navale 84, 00146, Roma, Italy
| | - Luis E Coronas
- Secció de Física Estadística i Interdisciplinària-Departament de Física de la Matèria Condensada, Universitat de Barcelona, & Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, C. Martí i Franquès 1, 08028, Barcelona, Spain
| | - Horacio R Corti
- Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina
| | - Ingrid de Almeida Ribeiro
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, UNICAMP, 13083-859, Campinas, São Paulo, Brazil
| | - Maurice de Koning
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, UNICAMP, 13083-859, Campinas, São Paulo, Brazil
- Center for Computing in Engineering & Sciences, Universidade Estadual de Campinas, UNICAMP, 13083-861, Campinas, São Paulo, Brazil
| | - Giancarlo Franzese
- Secció de Física Estadística i Interdisciplinària-Departament de Física de la Matèria Condensada, Universitat de Barcelona, & Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, C. Martí i Franquès 1, 08028, Barcelona, Spain
| | - Violeta Fuentes-Landete
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, A-6020, Innsbruck, Austria
| | - Catalin Gainaru
- Fakultät Physik, Technische Universität Dortmund, 44221, Dortmund, Germany
| | - Thomas Loerting
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, A-6020, Innsbruck, Austria
| | | | - Peter H Poole
- Department of Physics, St. Francis Xavier University, Antigonish, NS, B2G 2W5, Canada
| | - Mauro Rovere
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, Via della Vasca Navale 84, 00146, Roma, Italy
| | - Francesco Sciortino
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 5, 00185, Roma, Italy
| | - Christina M Tonauer
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, A-6020, Innsbruck, Austria
| | - Gustavo A Appignanesi
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Avenida Alem 1253, 8000, Bahía Blanca, Argentina
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3
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Zanetti-Polzi L, Amadei A, Daidone I. Segregation on the nanoscale coupled to liquid water polyamorphism in supercooled aqueous ionic-liquid solution. J Chem Phys 2021; 155:104502. [PMID: 34525825 DOI: 10.1063/5.0061659] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The most intriguing hypothesis explaining many water anomalies is a metastable liquid-liquid phase transition (LLPT) at high pressure and low temperatures, experimentally hidden by homogeneous nucleation. Recent infrared spectroscopic experiments showed that upon addition of hydrazinium trifluoroacetate to water, the supercooled ionic solution undergoes a sharp, reversible LLPT at ambient pressure, possible offspring of that in pure water. Here, we calculate the temperature-dependent signature of the OH-stretching band, reporting on the low/high density phase of water, in neat water and in the same experimentally investigated ionic solution. The comparison between the infrared signature of the pure liquid and that of the ionic solution can be achieved only computationally, providing insight into the nature of the experimentally observed phase transition and allowing us to investigate the effects of ionic compounds on the high to low density supercooled liquid water transition. We show that the experimentally observed crossover behavior in the ionic solution can be reproduced only if the phase transition between the low- and high-density liquid states of water is coupled to a mixing-unmixing transition between the water component and the ions: at low temperatures, water and ions are separated and the water component is a low density liquid. At high temperatures, water and ions get mixed and the water component is a high-density liquid. The separation at low temperatures into ion-rich and ion-poor regions allows unveiling the polyamorphic nature of liquid water, leading to a crossover behavior resembling that observed in supercooled neat water under high pressure.
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Affiliation(s)
- Laura Zanetti-Polzi
- Center S3, CNR-Institute of Nanoscience, Via Campi 213/A, 41125 Modena, Italy
| | - Andrea Amadei
- Department of Chemical and Technological Sciences, University of Rome "Tor Vergata", Via della Ricerca Scientifica, I-00185 Rome, Italy
| | - Isabella Daidone
- Department of Physical and Chemical Sciences, University of L'Aquila, via Vetoio (Coppito 1), 67010 L'Aquila, Italy
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4
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Lane PD, Reichenbach J, Farrell AJ, Ramakers LAI, Adamczyk K, Hunt NT, Wynne K. Experimental observation of nanophase segregation in aqueous salt solutions around the predicted liquid-liquid transition in water. Phys Chem Chem Phys 2020; 22:9438-9447. [PMID: 32314750 DOI: 10.1039/c9cp06082k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The liquid-liquid transition in supercooled liquid water, predicted to occur around 220 K, is controversial due to the difficulty of studying it caused by competition from ice crystallization (the so-called "no man's land"). In aqueous solutions, it has been predicted to give rise to phase separation on a nanometer scale between a solute-rich high-density phase and a water-rich low-density phase. Here we report direct experimental evidence for the formation of a nanosegregated phase in eutectic aqueous solutions of LiCl and LiSCN where the presence of crystalline water can be experimentally excluded. Femtosecond infrared and Raman spectroscopies are used to determine the temperature-dependent structuring of water, the solvation of the SCN- anion, and the size of the phase segregated domains.
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Affiliation(s)
- Paul D Lane
- Department of Physics, SUPA, University of Strathclyde, Glasgow, UK.
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5
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Bachler J, Handle PH, Giovambattista N, Loerting T. Glass polymorphism and liquid-liquid phase transition in aqueous solutions: experiments and computer simulations. Phys Chem Chem Phys 2019; 21:23238-23268. [PMID: 31556899 DOI: 10.1039/c9cp02953b] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
One of the most intriguing anomalies of water is its ability to exist as distinct amorphous ice forms (glass polymorphism or polyamorphism). This resonates well with the possible first-order liquid-liquid phase transition (LLPT) in the supercooled state, where ice is the stable phase. In this Perspective, we review experiments and computer simulations that search for LLPT and polyamorphism in aqueous solutions containing salts and alcohols. Most studies on ionic solutes are devoted to NaCl and LiCl; studies on alcohols have mainly focused on glycerol. Less attention has been paid to protein solutions and hydrophobic solutes, even though they reveal promising avenues. While all solutions show polyamorphism and an LLPT only in dilute, sub-eutectic mixtures, there are differences regarding the nature of the transition. Isocompositional transitions for varying mole fractions are observed in alcohol but not in ionic solutions. This is because water can surround alcohol molecules either in a low- or high-density configuration whereas for ionic solutes, the water ion hydration shell is forced into high-density structures. Consequently, the polyamorphic transition and the LLPT are prevented near the ions, but take place in patches of water within the solutions. We highlight discrepancies and different interpretations within the experimental community as well as the key challenges that need consideration when comparing experiments and simulations. We point out where reinterpretation of past studies helps to draw a unified, consistent picture. In addition to the literature review, we provide original experimental results. A list of eleven open questions that need further consideration is identified.
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Affiliation(s)
- Johannes Bachler
- Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria.
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6
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Bove LE, Pietrucci F, Saitta AM, Klotz S, Teixeira J. On the link between polyamorphism and liquid-liquid transition: The case of salty water. J Chem Phys 2019; 151:044503. [DOI: 10.1063/1.5100959] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Livia E. Bove
- Dipartimento di Fisica, Università di Roma ‘La Sapienza’, 00185 Roma, Italy
- Sorbonne Université, CNRS UMR 7590, IMPMC, 75005 Paris, France
| | - Fabio Pietrucci
- Sorbonne Université, CNRS UMR 7590, IMPMC, 75005 Paris, France
| | - A. Marco Saitta
- Sorbonne Université, CNRS UMR 7590, IMPMC, 75005 Paris, France
| | - Stefan Klotz
- Sorbonne Université, CNRS UMR 7590, IMPMC, 75005 Paris, France
| | - José Teixeira
- Laboratoire Léon Brillouin (CEA/CNRS), CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
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7
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Bove LE, Ranieri U. Salt- and gas-filled ices under planetary conditions. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20180262. [PMID: 30982457 PMCID: PMC6501915 DOI: 10.1098/rsta.2018.0262] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/26/2019] [Indexed: 06/09/2023]
Abstract
In recent years, evidence has emerged that solid water can contain substantial amounts of guest species, such as small gas molecules-in gas hydrate structures-or ions-in salty ice structures-and that these 'filled' ice structures can be stable under pressures of tens of Gigapascals and temperatures of hundreds of Kelvins. The inclusion of guest species can strongly modify the density, vibrational, diffusive and conductivity properties of ice under high pressure, and promote novel exotic properties. In this review, we discuss our experimental findings and molecular dynamics simulation results on the structures formed by salt- and gas-filled ices, their unusual properties, and the unexpected dynamical phenomena observed under pressure and temperature conditions relevant for planetary interiors modelling. This article is part of the theme issue 'The physics and chemistry of ice: scaffolding across scales, from the viability of life to the formation of planets'.
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Affiliation(s)
- Livia E. Bove
- Dipartimento di Fisica, Universitá di Roma ‘La Sapienza’, 00185Roma, Italy
- Sorbonne Université, CNRS UMR 7590, IMPMC, 75005 Paris, France
- EPSL, IPHYS, École polytechnique fédérale de Lausanne, Station 3, CH-1015 Lausanne, Switzerland
| | - Umbertoluca Ranieri
- Sorbonne Université, CNRS UMR 7590, IMPMC, 75005 Paris, France
- EPSL, IPHYS, École polytechnique fédérale de Lausanne, Station 3, CH-1015 Lausanne, Switzerland
- Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble, France
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8
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Ruiz GN, Amann-Winkel K, Bove LE, Corti HR, Loerting T. Calorimetric study of water's two glass transitions in the presence of LiCl. Phys Chem Chem Phys 2018; 20:6401-6408. [PMID: 29442107 PMCID: PMC5831115 DOI: 10.1039/c7cp08677f] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 01/31/2018] [Indexed: 11/21/2022]
Abstract
A DSC study of dilute glassy LiCl aqueous solutions in the water-dominated regime provides direct evidence of a glass-to-liquid transition in expanded high density amorphous (eHDA)-type solutions. Similarly, low density amorphous ice (LDA) exhibits a glass transition prior to crystallization to ice Ic. Both glass transition temperatures are independent of the salt concentration, whereas the magnitude of the heat capacity increase differs. By contrast to pure water, the glass transition endpoint for LDA can be accessed in LiCl aqueous solutions above 0.01 mole fraction. Furthermore, we also reveal the endpoint for HDA's glass transition, solving the question on the width of both glass transitions. This suggests that both equilibrated HDL and LDL can be accessed in dilute LiCl solutions, supporting the liquid-liquid transition scenario to understand water's anomalies.
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Affiliation(s)
- Guadalupe N. Ruiz
- Institute of Physical Chemistry , University of Innsbruck , Innrain 52c , 6020 Innsbruck , Austria .
- Departament de Física e Enginyeria Nuclear , Universitat Politècnica de Catalunya , 08028 , Barcelona , Spain
| | - Katrin Amann-Winkel
- Institute of Physical Chemistry , University of Innsbruck , Innrain 52c , 6020 Innsbruck , Austria .
- Department of Physics , AlbaNova University Center , 10691 Stockolm , Sweden
| | - Livia E. Bove
- Institut de Mineralogie et de Physique des Milieux Condenses , CNRS-Universitè P.et M. Curie , 4 place de Jussieu , 75005 Paris , France
- Institute of Condensed Matter Physics , Ecole Polytechnique Fédérale de Lausanne , Lausanne , Switzerland
| | - Horacio R. Corti
- Departamento de Física de la Materia Condensada , Comisión Nacional de Energía Atómica , San Martín , Buenos Aires , Argentina
- Instituto de Química Física de los Materiales , Medio Ambiente y Energía , Universidad de Buenos Aires , Ciudad Autónoma de Buenos Aires , Argentina
| | - Thomas Loerting
- Institute of Physical Chemistry , University of Innsbruck , Innrain 52c , 6020 Innsbruck , Austria .
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9
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Li RZ, Liu YY, Yang M. Microsolvation of lithium iodide dimer studied by ab initio calculations. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.06.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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10
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Mamontov E. Microscopic diffusion in hydrated encysted eggs of brine shrimp. Biochim Biophys Acta Gen Subj 2017; 1861:2382-2390. [PMID: 28549919 DOI: 10.1016/j.bbagen.2017.05.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 05/07/2017] [Accepted: 05/23/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND We have studied microscopic diffusion of water in fully hydrated encysted eggs of brine shrimp (Artemia). METHODS We have utilized quasielastic neutron scattering. RESULTS Dry eggs of brine shrimp were rehydrated using (1) water without additives, (2) eutectic mixture of water and dimethyl sulfoxide, and (3) a concentrated aqueous solution of lithium chloride. Despite the complexity of the hydrated multicellular organism, measurable microscopic diffusivity of water is rather well defined. Pure hydration water in eggs exhibits freezing temperature depression, whereas hydration water in eggs mixed with dimethyl sulfoxide or lithium chloride does not crystallize at all. CONCLUSIONS The characteristic size of the voids occupied by water or aqueous solvents in hydrated brine shrimp eggs is between 2 and 10nm. Those voids are accessible to co-solvents such as dimethyl sulfoxide and lithium chloride. There is no evidence of intracellular water in the hydrated eggs. GENERAL SIGNIFICANCE The lack of intracellular water in the fully hydrated (but still under arrested development) state must be linked to the unique resilience against adverse environmental factors documented not only for the anhydrous, but also hydrated encysted eggs of brine shrimp.
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Affiliation(s)
- E Mamontov
- Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
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11
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Borreguero JM, Mamontov E. Disruption of Hydrogen-Bonding Network Eliminates Water Anomalies Normally Observed on Cooling to Its Calorimetric Glass Transition. J Phys Chem B 2017; 121:4168-4173. [PMID: 28398063 DOI: 10.1021/acs.jpcb.7b01226] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The calorimetric glass-transition temperature of water is 136 K, but extrapolation of thermodynamic and relaxation properties of water from ambient temperature to below its homogeneous nucleation temperature TH = 235 K predicts divergence at TS = 228 K. The "no-man's land" between the TH and glassy water crystallization temperature of 150 K, which is encountered on warming up from the vitrified state, precludes a straightforward reconciliation of the two incompatible temperature dependences of water properties, above 235 K and below 150 K. The addition of lithium chloride to water allows bypassing both TH and TS on cooling, resulting in the dynamics with no features except the calorimetric glass transition, still at 136 K. We show that lithium chloride prevents hydrogen-bonding network completion in water on cooling, as manifested, in particular, in changing microscopic diffusion mechanism of the water molecules. Thus thermodynamic and relaxation peculiarities exhibited by pure water on cooling to its glass transition, such as the existence of the TH and TS, must be associated specifically with the hydrogen-bonding network.
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Affiliation(s)
- Jose M Borreguero
- Neutron Data Analysis and Visualization Division, Neutron Sciences Directorate, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Eugene Mamontov
- Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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12
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Demontis P, Gulín-González J, Masia M, Sant M, Suffritti GB. The interplay between dynamic heterogeneities and structure of bulk liquid water: A molecular dynamics simulation study. J Chem Phys 2016; 142:244507. [PMID: 26133441 DOI: 10.1063/1.4922930] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In order to study the interplay between dynamical heterogeneities and structural properties of bulk liquid water in the temperature range 130-350 K, thus including the supercooled regime, we use the explicit trend of the distribution functions of some molecular properties, namely, the rotational relaxation constants, the atomic mean-square displacements, the relaxation of the cross correlation functions between the linear and squared displacements of H and O atoms of each molecule, the tetrahedral order parameter q and, finally, the number of nearest neighbors (NNs) and of hydrogen bonds (HBs) per molecule. Two different potentials are considered: TIP4P-Ew and a model developed in this laboratory for the study of nanoconfined water. The results are similar for the dynamical properties, but are markedly different for the structural characteristics. In particular, for temperatures higher than that of the dynamic crossover between "fragile" (at higher temperatures) and "strong" (at lower temperatures) liquid behaviors detected around 207 K, the rotational relaxation of supercooled water appears to be remarkably homogeneous. However, the structural parameters (number of NNs and of HBs, as well as q) do not show homogeneous distributions, and these distributions are different for the two water models. Another dynamic crossover between "fragile" (at lower temperatures) and "strong" (at higher temperatures) liquid behaviors, corresponding to the one found experimentally at T(∗) ∼ 315 ± 5 K, was spotted at T(∗) ∼ 283 K and T(∗) ∼ 276 K for the TIP4P-Ew and the model developed in this laboratory, respectively. It was detected from the trend of Arrhenius plots of dynamic quantities and from the onset of a further heterogeneity in the rotational relaxation. To our best knowledge, it is the first time that this dynamical crossover is detected in computer simulations of bulk water. On the basis of the simulation results, the possible mechanisms of the two crossovers at molecular level are discussed.
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Affiliation(s)
- Pierfranco Demontis
- Dipartimento di Chimica e Farmacia, Università degli studi di Sassari, Sassari, Italy
| | - Jorge Gulín-González
- Grupo de Matemática y Física Computacionales, Universidad de las Ciencias Informáticas (UCI), Carretera a San Antonio de los Baños, Km 21/2, La Lisa, La Habana, Cuba
| | - Marco Masia
- Dipartimento di Chimica e Farmacia, Università degli studi di Sassari, Sassari, Italy
| | - Marco Sant
- Dipartimento di Chimica e Farmacia, Università degli studi di Sassari, Sassari, Italy
| | - Giuseppe B Suffritti
- Dipartimento di Chimica e Farmacia, Università degli studi di Sassari, Sassari, Italy
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13
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Ruiz GN, Bove LE, Corti HR, Loerting T. Pressure-induced transformations in LiCl-H2O at 77 K. Phys Chem Chem Phys 2015; 16:18553-62. [PMID: 25072395 DOI: 10.1039/c4cp01786b] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A systematic study of the properties of high-density amorphous ice (HDA) in the presence of increasing amounts of salt is missing, especially because it is challenging to avoid ice crystallization upon cooling the pressurized liquid. In order to be able to study HDA also in the presence of small amounts of salt, we have investigated the transformation behaviour of quenched aqueous LiCl solutions (mole fraction x < 0.25) upon pressurization in a piston-cylinder setup at 77 K. The sample properties were characterized by in situ dilatometry under high pressure conditions and after recovery by ex situ powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC) at ambient pressure. Two regimes can be identified, with a rather sharp switch at about x = 0.12. At x < 0.12 the samples show the phenomenology also known for pure water samples. They are composed mainly of hexagonal ice (Ih) and experience pressure-induced amorphization to HDA at P > 1 GPa. The observed densification is consistent with the idea that a freeze concentrated LiCl solution of x = 0.14 (R = 6) segregates, which transforms to the glassy state upon cooling, and that the densification is only due to the Ih → HDA transition. Also the XRD patterns and DSC scans are almost unaffected by the presence of the segregated glassy LiCl solution. Upon heating at ambient pressure HDA experiences the polyamorphic transition to low-density amorphous ice (LDA) at ∼120 K, even at x ∼ 0.10. Based on the latent heat evolved in the transition we suggest that almost all water in the sample transforms to an LDA-like state, even the water in the vicinity of the ions. The glassy LiCl solution acts as a spectator that does not shift the transformation temperature significantly and experiences a glass-to-liquid transition at ∼140 K prior to the crystallization to cubic ice. By contrast, at x > 0.12 the phenomenology completely changes and is now dominated by the salt. Hexagonal ice no longer forms upon quenching the LiCl solution, but instead LDA forms. A broad pressure-induced transformation at >0.6 GPa can be attributed to the densification of LDA, the glassy LiCl solution and/or glassy hydrates.
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Affiliation(s)
- G N Ruiz
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, (1428), Buenos Aires, Argentina
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14
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Ludl AA, Bove LE, Saitta AM, Salanne M, Hansen TC, Bull CL, Gaal R, Klotz S. Structural characterization of eutectic aqueous NaCl solutions under variable temperature and pressure conditions. Phys Chem Chem Phys 2015; 17:14054-63. [PMID: 25955540 DOI: 10.1039/c5cp00224a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The structure of amorphous NaCl solutions produced by fast quenching is studied as a function of pressure, up to 4 GPa, by combined neutron diffraction experiments and classical molecular dynamics simulations. Similarly to LiCl solutions the system amorphizes at ambient pressure in a dense phase structurally similar to the e-HDA phase in pure water. The measurement of the static structure factor as a function of pressure allowed us to validate a new polarizable force field developed by Tazi et al., 2012, never tested under non-ambient conditions. We infer from simulations that the hydration shells of Na(+) cations form well defined octahedra composed of both H2O molecules and Cl(-) anions at low pressure. These octahedra are gradually broken by the seventh neighbour moving into the shell of first neighbours yielding an irregular geometry. In contrast to LiCl solutions and pure water, the system does not show a polyamorphic transition under pressure. This confirms that the existence of polyamorphism relies on the tetrahedral structure of water molecules, which is broken here.
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Affiliation(s)
- A-A Ludl
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7590, IMPMC, F-75005, Paris, France.
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15
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Hudait A, Molinero V. Ice Crystallization in Ultrafine Water–Salt Aerosols: Nucleation, Ice-Solution Equilibrium, and Internal Structure. J Am Chem Soc 2014; 136:8081-93. [DOI: 10.1021/ja503311r] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Arpa Hudait
- Department
of Chemistry, The University of Utah, 315 South 1400 East, Salt
Lake City, Utah 84112-0850, United States
| | - Valeria Molinero
- Department
of Chemistry, The University of Utah, 315 South 1400 East, Salt
Lake City, Utah 84112-0850, United States
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16
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Suffritti GB, Demontis P, Gulín-González J, Masia M. Distributions of single-molecule properties as tools for the study of dynamical heterogeneities in nanoconfined water. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:155103. [PMID: 24675399 DOI: 10.1088/0953-8984/26/15/155103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The explicit trend of the distribution functions of single-molecule rotational relaxation constants and atomic mean-square displacement are used to study the dynamical heterogeneities in nanoconfined water. The trend of the single-molecule properties distributions is related to the dynamic heterogeneities, and to the dynamic crossovers found in water clusters of different shapes and sizes and confined in a variety of zeolites. This was true in all the cases that were considered, in spite of the various shapes and sizes of the clusters. It is confirmed that the high temperature dynamical crossover occurring in the temperature range 200-230 K can be interpreted at a molecular level as the formation of almost translationally rigid clusters, characterized by some rotational freedom, hydrogen bond exchange and translational jumps as cage-to-cage processes. We also suggest a mechanism for the low temperature dynamical crossover (LTDC), falling in the temperature range 150-185 K, through which the adsorbed water clusters are made of nearly rigid sub-clusters, slightly mismatched, and thus permitting a relatively free librational motion at their borders. It appears that the condition required for LTDC to occur is the presence of highly heterogeneous environments for the adsorbed molecules, with some dangling hydrogen bonds or weaker than water-water hydrogen bonds. Under these conditions some dynamics are permitted at very low temperature, although most rotational motion is frozen. Therefore, it is unlikely, though not entirely excluded, that LTDC will be found in supercooled bulk water where no heterogeneous interface is present.
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Affiliation(s)
- G B Suffritti
- Dipartimento di Chimica e Farmacia, Università di Sassari and INSTM, Unità di ricerca di Sassari, Via Vienna 2, I-07100 Sassari, Italy
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