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Hung ST, Roget SA, Fayer MD. Effects of Nanoconfinement on Dynamics in Concentrated Aqueous Magnesium Chloride Solutions. J Phys Chem B 2024; 128:5513-5527. [PMID: 38787935 DOI: 10.1021/acs.jpcb.4c01639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2024]
Abstract
Water behavior in various natural and manufactured settings is influenced by confinement in organic or inorganic frameworks and the presence of solutes. Here, the effects on dynamics from both confinement and the addition of solutes are examined. Specifically, water and ion dynamics in concentrated (2.5-4.2 m) aqueous magnesium chloride solutions confined in mesoporous silica (2.8 nm pore diameter) were investigated using polarization selective pump-probe and 2D infrared spectroscopies. Fitting the rotational and spectral diffusion dynamics measured by the vibrational probe, selenocyanate, with a previously developed two-state model revealed distinct behaviors at the interior of the silica pores (core state) and near the wall of the confining framework (shell state). The shell dynamics are noticeably slower than the bulk, or core, dynamics. The concentration-dependent slowing of the dynamics aligns with behavior in the bulk solutions, but the spectrally separated water-associated and Mg2+-associated forms of the selenocyanate probe exhibit different responses to confinement. The disparity in the complete reorientation times is larger upon confinement, but the spectral diffusion dynamics become more similar near the silica surface. The length scales that characterize the transition from surface-influenced to bulk-like behavior for the salt solutions in the pores are discussed and compared to those of pure water and an organic solvent confined in the same pores. These comparisons offer insights into how confinement modulates the properties of different liquids.
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Affiliation(s)
- Samantha T Hung
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Sean A Roget
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Michael D Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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Baum M, Rieutord F, Juranyi F, Rey C, Rébiscoul D. Dynamical and Structural Properties of Water in Silica Nanoconfinement: Impact of Pore Size, Ion Nature, and Electrolyte Concentration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10780-10794. [PMID: 31345036 DOI: 10.1021/acs.langmuir.9b01434] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this study, we characterized the structure and the dynamics at a picosecond scale of water molecules in aqueous solutions with cations having various kosmotropic properties (XCl2 where X = Ba2+, Ca2+, and Mg2+) confined in highly ordered mesoporous silica (MCM-41 and grafted MCM-41) by Fourier transform infrared spectroscopy and quasi-elastic neutron scattering. We pinpointed the critical pore size and the electrolyte concentration at which the influence of the ion nature becomes the main factor affecting the water properties. These results suggest that whatever the ions kosmotropic properties, for pore sizes ϕp < 2.6 nm and [XCl2] ≤ 1 M, the water dynamics is mainly slowed down by the size of the confinement. For pore sizes of 6.6 nm, the water dynamics depends on the concentration and kosmotropic properties of the ion more than on the confinement. The water properties within the interfacial layer were also assessed and related to the surface ion excesses obtained by sorption isotherms. We showed that, for pore sizes ϕp ≥ 2.6 nm, the surface ion excess at the pore surface is the main driver affecting the structural properties of water molecules and their dynamics within the interfacial layer.
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Affiliation(s)
- Markus Baum
- CEA, ICSM - UMR 5257 CEA-CNRS-UM-ENSCM , 30207 Bagnols-sur-Cèze Cedex, France
| | | | - Fanni Juranyi
- Paul-Scherrer-Institute , 5232 Villigen PSI, Switzerland
| | - Cyrielle Rey
- CEA, ICSM - UMR 5257 CEA-CNRS-UM-ENSCM , 30207 Bagnols-sur-Cèze Cedex, France
| | - Diane Rébiscoul
- CEA, ICSM - UMR 5257 CEA-CNRS-UM-ENSCM , 30207 Bagnols-sur-Cèze Cedex, France
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Osti NC, Naguib M, Ostadhossein A, Xie Y, Kent PRC, Dyatkin B, Rother G, Heller WT, van Duin ACT, Gogotsi Y, Mamontov E. Effect of Metal Ion Intercalation on the Structure of MXene and Water Dynamics on its Internal Surfaces. ACS APPLIED MATERIALS & INTERFACES 2016; 8:8859-8863. [PMID: 27010763 DOI: 10.1021/acsami.6b01490] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
MXenes are a recently discovered class of 2D materials with an excellent potential for energy storage applications. Because MXene surfaces are hydrophilic and attractive interaction forces between the layers are relatively weak, water molecules can spontaneously intercalate at ambient humidity and significantly influence the key properties of this 2D material. Using complementary X-ray and neutron scattering techniques, we demonstrate that intercalation with potassium cations significantly improves structural homogeneity and water stability in MXenes. In agreement with molecular dynamics simulations, intercalated potassium ions reduce the water self-diffusion coefficient by 2 orders of magnitude, suggesting greater stability of hydrated MXene against changing environmental conditions.
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Affiliation(s)
- Naresh C Osti
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Michael Naguib
- Materials Science and Technology Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Alireza Ostadhossein
- Department of Engineering Science and Mechanics, Pennsylvania State University , University Park, Pennsylvania 16801, United States
| | - Yu Xie
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Paul R C Kent
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Computer Science and Mathematics Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Boris Dyatkin
- Department of Materials Science and Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Gernot Rother
- Chemical Science Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - William T Heller
- Biology and Soft Matter Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Adri C T van Duin
- Department of Mechanical and Nuclear Engineering, Pennsylvania State University , University Park, Pennsylvania 16801, United States
| | - Yury Gogotsi
- Department of Materials Science and Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Eugene Mamontov
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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Mamontov E, De Francesco A, Formisano F, Laloni A, Sani L, Leu BM, Said AH, Kolesnikov AI. Water dynamics in a lithium chloride aqueous solution probed by Brillouin neutron and x-ray scattering. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:064102. [PMID: 22277241 DOI: 10.1088/0953-8984/24/6/064102] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We studied the collective excitations in an aqueous solution of lithium chloride over the temperature range of 270-205 K using neutron and x-ray Brillouin scattering. Both neutron and x-ray experiments revealed the presence of low- and high-frequency excitations, similar to the low- and high-frequency excitations in pure water. These two excitations were detectable through the entire temperature range of the experiment, at all probed values of the scattering momentum transfer (0.2 Å(-1) < Q < 1.8 Å(-1)). A wider temperature range was investigated using elastic intensity neutron and x-ray scans. Clear evidence of the crossover in the dynamics of the water molecules in the solution was observed in the single-particle relaxational dynamics on the µeV (nanosecond) time scale, but not in the collective dynamics on the meV (picosecond) time scale.
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Affiliation(s)
- E Mamontov
- Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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Affiliation(s)
- Alberto Striolo
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK 73019, U.S.A
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Structure and Dynamics of Fluids in Microporous and Mesoporous Earth and Engineered Materials. NEUTRON APPLICATIONS IN EARTH, ENERGY AND ENVIRONMENTAL SCIENCES 2009. [DOI: 10.1007/978-0-387-09416-8_19] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Dynamics of water in LiCl and CaCl2 aqueous solutions confined in silica matrices: A backscattering neutron spectroscopy study. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2008.05.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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