1
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Sun L, Wang J, Chen Y. Coalescence of multiple droplets induced by a constant DC electric field. PLoS One 2024; 19:e0300925. [PMID: 38593131 PMCID: PMC11003697 DOI: 10.1371/journal.pone.0300925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/06/2024] [Indexed: 04/11/2024] Open
Abstract
In this work, the electro-coalescence process of three nanodroplets under a constant DC electric field is investigated via molecular dynamics simulations (MD), aiming to explore the electric manipulation of multiple droplets coalescence on the molecular level. The symmetrical and asymmetrical dynamic evolutions of electrocoalescence process can be observed. Our MD simulations show that there are two types of critical electric fields to induce the special dynamics. The chain configuration can be formed, when one of the critical electric field is exceeded, referred to as Ecc. On the other hand, there is another critical electric field to change the coalescence pattern from complete coalescence to partial coalescence, the so-called Ecn. Finally, we find that the use of the pulsed DC electric field can overcome the drawbacks of the constant DC electric field in the crude oil industry, and the mechanisms behind the suppressed effect of the water chain or non-coalescence are further revealed.
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Affiliation(s)
- Liwei Sun
- School of Mechanical Engineering, Changchun Automobile Industry Institute, Changchun, China
| | - Jian Wang
- College of Computer Science and Technology, Jilin University, Changchun, China
| | - Yanhui Chen
- School of Mechanical Engineering, Changchun Automobile Industry Institute, Changchun, China
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2
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Kumar S, Bagchi B. Anomalous Concentration Dependence of Viscosity: Hidden Role of Cross-Correlations in Aqueous Electrolyte Solutions. J Phys Chem B 2023; 127:11031-11044. [PMID: 38101333 DOI: 10.1021/acs.jpcb.3c05117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
The viscosity of aqueous electrolyte solutions exhibits well-known composition-dependent anomalies that show certain definitive trends and universal features. The viscosity of LiCl and NaCl solutions increases with concentration in a monotonic fashion, while solutions of KCl, RbCl, and CsCl exhibit a more complex behavior. Here, the viscosity first decreases and then increases with increasing concentration, with a rather broad minimum at intermediate concentrations (ca. 1-3 m). To unearth the origin of such puzzling behavior, we carried out detailed molecular-level analyses by interrogating the exact Green-Kubo expression of viscosity in terms of the stress-stress time correlation function (SS-TCF). The total SS-TCF can be decomposed into a collection of three self- and three cross-SS-TCFs arising from the three constituent components (water, cations, and anions). Mode coupling theory (MCT) analysis for the friction on ions and the viscosity of the solution suggests the possible importance of two-particle static and time-dependent cross-correlations between water and the ions. We calculate the viscosity and other dynamical properties for all five electrolyte (LiCl, NaCl, KCl, RbCl, and CsCl) solutions over a range of concentrations, using two models of water (SPC/E and TIP4P/2005). The total viscosity derives non-negligible contributions from all of the terms. The cross-correlations are found to be surprisingly large and seen to play a hidden role in the concentration dependence. However, the importance of cross-correlations is often not discussed. Our study leads to a theoretical understanding of the microscopic origin of the observed anomalies in the composition dependence of viscosity across all five electrolytes.
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Affiliation(s)
- Shubham Kumar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Biman Bagchi
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
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3
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Zhu J, Zhao Z, Li X, Wei Y. Structural and dynamical properties of concentrated alkali- and alkaline-earth metal chloride aqueous solutions. J Chem Phys 2023; 159:214503. [PMID: 38054516 DOI: 10.1063/5.0178123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/12/2023] [Indexed: 12/07/2023] Open
Abstract
Concentrated ionic aqueous electrolytes possess a diverse array of applications across various fields, particularly in the field of energy storage. Despite extensive examination, the intricate relationships and numerous physical mechanisms underpinning diverse phenomena remain incompletely understood. Molecular dynamics simulations are employed to probe the attributes of aqueous solutions containing LiCl, NaCl, KCl, MgCl2, and CaCl2, spanning various solute fractions. The primary emphasis of the simulations is on unraveling the intricate interplay between these attributes and the underlying physical mechanisms. The configurations of cation-Cl- and Cl--Cl- pairs within these solutions are disclosed. As the solute fraction increases, consistent trends manifest regardless of solute type: (i) the number of hydrogen bonds formed by the hydration water surrounding ions decreases, primarily attributed to the growing presence of counter ions in proximity to the hydration water; (ii) the hydration number of ions exhibits varying trends influenced by multiple factor; and (iii) the diffusion of ions slows down, attributed to the enhanced confinement and rebound of cations and Cl- ions from the surrounding atoms, concurrently coupled with the changes in ion vibration modes. In our analysis, we have, for the first time, clarified the reasons behind the slowing down of the diffusion of the ions with increasing solute fraction. Our research contributes to a better understanding and manipulation of the attributes of ionic aqueous solutions and may help designing high-performance electrolytes.
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Affiliation(s)
- Jianzhuo Zhu
- Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, China
| | - Zhuodan Zhao
- Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, China
| | - Xingyuan Li
- Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, China
| | - Yong Wei
- School of Information Science and Engineering, Yanshan University, Qinhuangdao 066004, China
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4
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Hua H, Huang B, Yang X, Cheng J, Zhang P, Zhao J. Toward a molecular understanding of the conductivity of lithium-ion conducting polyanion polymer electrolytes by molecular dynamics simulation. Phys Chem Chem Phys 2023; 25:29894-29904. [PMID: 37901964 DOI: 10.1039/d3cp02225k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
Abstract
With the improved lithium-ion transference number near unity, the low conductivity of single lithium-ion conducting solid polymer electrolytes (SLIC-SPEs) still hinders their application in high-rate batteries. Though some empirical conclusions on the conducting mechanism of SLIC-SPEs have been obtained, a more comprehensive study on the quantitative relationship between the molecular structure factors and ionic conduction performance is expected. In this study, a model structure that contains adjustable main chain and anion groups in the polyethylene oxide (PEO) matrix was used to clarify the influence of molecular structural factors on ionic conductivity and electrochemical stability of SLIC-SPEs. The anionic group was further disassembled into the intermediate group and end group while the main chain structure was distinguished into different degrees of polymerization and various lengths of the spacers between anions. Therefore, a well-defined molecular structure was employed to describe its relationship with ionic conductivity. In addition, the dissociation degree of salts and mobility of ions changing with the molecular structure were also discussed to explore the fundamental causes of conductivity. It can be concluded that the anion group affects the conductivity mainly via the dissociation degree, while the main chain structure impacts the conductivity by both dissociation degree and mobility.
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Affiliation(s)
- Haiming Hua
- College of Chemistry and Chemical Engineering, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, State Key Laboratory of Physical Chemistry of Solid Surfaces, Engineering Research Center of Electrochemical Technology, Ministry of Education, Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen 361005, Fujian, China.
| | - Boyang Huang
- College of Chemistry and Chemical Engineering, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, State Key Laboratory of Physical Chemistry of Solid Surfaces, Engineering Research Center of Electrochemical Technology, Ministry of Education, Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen 361005, Fujian, China.
| | - Xueying Yang
- College of Energy, Xiamen University, Xiamen 361102, Fujian, China.
| | - Jun Cheng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
| | - Peng Zhang
- College of Energy, Xiamen University, Xiamen 361102, Fujian, China.
| | - Jinbao Zhao
- College of Chemistry and Chemical Engineering, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, State Key Laboratory of Physical Chemistry of Solid Surfaces, Engineering Research Center of Electrochemical Technology, Ministry of Education, Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen 361005, Fujian, China.
- College of Energy, Xiamen University, Xiamen 361102, Fujian, China.
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5
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Shock CJ, Stevens MJ, Frischknecht AL, Nakamura I. Molecular dynamics simulations of the dielectric constants of salt-free and salt-doped polar solvents. J Chem Phys 2023; 159:134507. [PMID: 37795785 DOI: 10.1063/5.0165481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/15/2023] [Indexed: 10/06/2023] Open
Abstract
We develop a Stockmayer fluid model that accounts for the dielectric responses of polar solvents (water, MeOH, EtOH, acetone, 1-propanol, DMSO, and DMF) and NaCl solutions. These solvent molecules are represented by Lennard-Jones (LJ) spheres with permanent dipole moments and the ions by charged LJ spheres. The simulated dielectric constants of these liquids are comparable to experimental values, including the substantial decrease in the dielectric constant of water upon the addition of NaCl. Moreover, the simulations predict an increase in the dielectric constant when considering the influence of ion translations in addition to the orientation of permanent dipoles.
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Affiliation(s)
- Cameron J Shock
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, USA
| | - Mark J Stevens
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Amalie L Frischknecht
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Issei Nakamura
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, USA
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6
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Maji D, Biswas R. Dielectric relaxation and dielectric decrement in ionic acetamide deep eutectic solvents: Spectral decomposition and comparison with experiments. J Chem Phys 2023; 158:2888209. [PMID: 37139998 DOI: 10.1063/5.0147378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/17/2023] [Indexed: 05/05/2023] Open
Abstract
Frequency-dependent dielectric relaxation in three deep eutectic solvents (DESs), (acetamide+LiClO4/NO3/Br), was investigated in the temperature range, 329 ≤ T/K ≤ 358, via molecular dynamics simulations. Subsequently, decomposition of the real and the imaginary components of the simulated dielectric spectra was carried out to separate the rotational (dipole-dipole), translational (ion-ion), and ro-translational (dipole-ion) contributions. The dipolar contribution, as expected, was found to dominate all the frequency-dependent dielectric spectra over the entire frequency regime, while the other two components together made tiny contributions only. The translational (ion-ion) and the cross ro-translational contributions appeared in the THz regime in contrast to the viscosity-dependent dipolar relaxations that dominated the MHz-GHz frequency window. Our simulations predicted, in agreement with experiments, anion-dependent decrement of the static dielectric constant (ɛs ∼ 20 to 30) for acetamide (ɛs ∼ 66) in these ionic DESs. Simulated dipole-correlations (Kirkwood g factor) indicated significant orientational frustrations. The frustrated orientational structure was found to be associated with the anion-dependent damage of the acetamide H-bond network. Single dipole reorientation time distributions suggested slowed down acetamide rotations but did not indicate presence of any "rotationally frozen" molecule. The dielectric decrement is, therefore, largely static in origin. This provides a new insight into the ion dependence of the dielectric behavior of these ionic DESs. A good agreement between the simulated and the experimental timescales was also noticed.
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Affiliation(s)
- Dhrubajyoti Maji
- Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector III, Salt Lake, Kolkata, West Bengal 700106, India
| | - Ranjit Biswas
- Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector III, Salt Lake, Kolkata, West Bengal 700106, India
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7
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Zhou K, Liu Z, Fan R, Zhao M, Luo L, Wang Y, Jiang Y, Lu Z, Tang J, Luo A, Guan T, Sun H, Zhou T, Dai C. A new methodology of understanding the mechanism of high shear wet granulation based on experiment and molecular dynamics stimulation. Int J Pharm 2023; 638:122923. [PMID: 37030641 DOI: 10.1016/j.ijpharm.2023.122923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/17/2023] [Accepted: 03/31/2023] [Indexed: 04/10/2023]
Abstract
In high shear wet granulation (HSWG), the interaction mechanism between binder and powder with different sugar content is still unclear. Herein, the law and mechanism of the interaction between binder and powder were studied on the molecular level by combining experiment analysis through the Kriging model and molecular dynamics (MD) simulation. For the sticky powder with high sugar content, the ethanol in the binder played a pivotal role in dispersing water into powders, and the amount of water determined the growth of granules. In the saturating stage, the reduction of sugar content facilitates the penetration of ethanol molecules. The concentration of ethanol determines whether the mixture is blended uniformly in the merging stage. The simulation results are consistent with the actual situation and explain the competition mechanism of interaction with binder and powder. Therefore, this research offers an efficient strategy for the in-depth understanding of the HSWG process where the powder is sticky, as well as providing guidelines for the practical application of preparation for TCM granules.
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Affiliation(s)
- Kangming Zhou
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Zeng Liu
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Renyu Fan
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Mengtao Zhao
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Linxiu Luo
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Yuting Wang
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Yanling Jiang
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Zheng Lu
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Jincao Tang
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Anqi Luo
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Tianbing Guan
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Huimin Sun
- NMPA Key Laboratory for Quality Research and Evaluation of Pharmaceutical Excipients, National Institutes for Food and Drug Control, Beijing 100050, China
| | - Taigang Zhou
- College of Chemistry and Chemical Engineering, State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China
| | - Chuanyun Dai
- Chongqing Key Laboratory of Industrial Fermentation Microorganisms, College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China.
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8
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Biswas A, Mallik BS. Direct Correlation between Short-Range Vibrational Spectral Diffusion and Localized Ion-Cage Dynamics of Water-in-Salt Electrolytes. J Phys Chem B 2023; 127:236-248. [PMID: 36575973 DOI: 10.1021/acs.jpcb.2c04391] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The molecular dynamics simulations of a "water-in-salt" electrolyte, lithium bis(trifluoromethyl sulfonyl) imide (LiNTf2), with a varying concentration range of 3 to 20 m were performed to establish a direct connection between a dynamic property like the ion-cage lifetime with the short-range vibrational stretching frequency shift of the used probe, HOD. The properties reported here are compared to that obtained from experiments performed at the same concentrations. The time-series wavelet transform was adopted as a preferable mathematical tool for calculating the instantaneous fluctuating frequencies of the probe O-D stretch mode and the concentration-dependent vibrational stretch spectral signature based on the variable functions associated with a particular chemical bond derived from classical molecular dynamics trajectories. The decay time constants of frequency fluctuations and the lifetime of the ion cage (τIC) were estimated as a function of salt concentration. Herein, we emphasize the correlation between the slowest time constant (τ3) of the decay of O-D stretch frequency fluctuations and the timescales associated with the lifetime of ion cages (τIC). The results exhibit that the existing relationships were also concentration-dependent. Therefore, this study highlights the connection between the ionic motions that regulate the overall system dynamics with the short-range vibrational frequency shift of the used probe, which was used similar to experiments. It also provides an understanding of the interionic interactions and the dynamical and spectral properties of the electrolytic mixtures. We establish a direct correlation between short-range frequency profile and localized ion-cage lifetime, which can fill the gap of understanding between viscosity, vibrational frequency, and ion-cage dynamics of electrolytes.
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Affiliation(s)
- Aritri Biswas
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy502285, Telangana, India
| | - Bhabani S Mallik
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy502285, Telangana, India
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9
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Biswas A, Mallik BS. Molecular Simulation-Guided Spectroscopy of Imidazolium-Based Ionic Liquids and Effects of Methylation on Ion-Cage and -Pair Dynamics. J Phys Chem B 2022; 126:8838-8850. [PMID: 36264223 DOI: 10.1021/acs.jpcb.2c04901] [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
Classical molecular dynamics simulations were performed to assess an atomistic interpretation of the ion-probe structural interactions in two typical ionic liquids (ILs), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIm][NTf2] and 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide [BDimIm][NTf2] through computational ultrafast spectroscopy. The nitrile stretching vibrations of the thiocyanate anion, [SCN]-, serve as the local mode of the ultrafast system dynamics within the imidazolium-based ionic liquid environment. The wavelet transform of classical trajectories determines the time-varying fluctuating frequencies and the stretch spectral signatures of SCN- in the normalized distribution. However, computational modeling of the two-dimensional (2D) spectra from the wavelet-derived vibrational frequencies yields time evolution of the local molecular structure along with the varied time-dependent dynamics of the spectral diffusion process. We calculated the frequency-frequency correlation functions (FFCFs), time correlations associated with the ion-pair and -cage dynamics, and mean square displacements as a function of time, depicting diffusive dynamics. The calculated results based on the pair correlation functions and the distribution of atomic density suggest that the hydrogen and methylated carbon at the two-position of the imidazolium ring of [BMIm] and [BDimIm] cations, respectively, strongly interact with the probe through the N of the thiocyanate anion rather than the S atom. The center-of-mass center-of-mass (COM-COM) cation-probe radial distribution functions (RDFs) in conjunction with the site-specific structural analysis further reveal well-structured interactions of the thiocyanate ion and [BMIm]+ cation rather than the [BDimIm] cation. In contrast, the anion-probe COM-COM RDFs depict weak interactive associations within the vibrational probe [SCN]- and [NTf2]- ions. Methylation at the two-position of the imidazolium ring predicts slower structural reorganization and breaking and reformation dynamics of the ion pairs and cages within the ionic liquid framework.
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Affiliation(s)
- Aritri Biswas
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy502285, Telangana, India
| | - Bhabani S Mallik
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy502285, Telangana, India
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10
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Lee WC, Ronghe A, Villalobos LF, Huang S, Dakhchoune M, Mensi M, Hsu KJ, Ayappa KG, Agrawal KV. Enhanced Water Evaporation from Å-Scale Graphene Nanopores. ACS NANO 2022; 16:15382-15396. [PMID: 36000823 PMCID: PMC9527801 DOI: 10.1021/acsnano.2c07193] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 08/19/2022] [Indexed: 05/26/2023]
Abstract
Enhancing the kinetics of liquid-vapor transition from nanoscale confinements is an attractive strategy for developing evaporation and separation applications. The ultimate limit of confinement for evaporation is an atom thick interface hosting angstrom-scale nanopores. Herein, using a combined experimental/computational approach, we report highly enhanced water evaporation rates when angstrom sized oxygen-functionalized graphene nanopores are placed at the liquid-vapor interface. The evaporation flux increases for the smaller nanopores with an enhancement up to 35-fold with respect to the bare liquid-vapor interface. Molecular dynamics simulations reveal that oxygen-functionalized nanopores render rapid rotational and translational dynamics to the water molecules due to a reduced and short-lived water-water hydrogen bonding. The potential of mean force (PMF) reveals that the free energy barrier for water evaporation decreases in the presence of nanopores at the atomically thin interface, which further explains the enhancement in evaporation flux. These findings can enable the development of energy-efficient technologies relying on water evaporation.
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Affiliation(s)
- Wan-Chi Lee
- Laboratory
of Advanced Separations (LAS), École
Polytechnique Fédérale de Lausanne (EPFL), Sion 1950, Switzerland
| | - Anshaj Ronghe
- Department
of Chemical Engineering, Indian Institute
of Science, Bangalore, 560012, India
| | - Luis Francisco Villalobos
- Laboratory
of Advanced Separations (LAS), École
Polytechnique Fédérale de Lausanne (EPFL), Sion 1950, Switzerland
| | - Shiqi Huang
- Laboratory
of Advanced Separations (LAS), École
Polytechnique Fédérale de Lausanne (EPFL), Sion 1950, Switzerland
| | - Mostapha Dakhchoune
- Laboratory
of Advanced Separations (LAS), École
Polytechnique Fédérale de Lausanne (EPFL), Sion 1950, Switzerland
| | - Mounir Mensi
- Institut
des Sciences et Ingénierie Chimiques (ISIC), EPFL, Sion 1950, Switzerland
| | - Kuang-Jung Hsu
- Laboratory
of Advanced Separations (LAS), École
Polytechnique Fédérale de Lausanne (EPFL), Sion 1950, Switzerland
| | - K. Ganapathy Ayappa
- Department
of Chemical Engineering, Indian Institute
of Science, Bangalore, 560012, India
| | - Kumar Varoon Agrawal
- Laboratory
of Advanced Separations (LAS), École
Polytechnique Fédérale de Lausanne (EPFL), Sion 1950, Switzerland
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11
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Hosseinzadeh Dehaghani Y, Assareh M, Feyzi F. Simultaneous Prediction of Equilibrium, Interfacial, and Transport Properties of CO 2-Brine Systems Using Molecular Dynamics Simulation: Applications to CO 2 Storage. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c02249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yasaman Hosseinzadeh Dehaghani
- Thermodynamics Research Laboratory, School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology (IUST), Tehran 16846-13114, Iran
| | - Mehdi Assareh
- Thermodynamics Research Laboratory, School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology (IUST), Tehran 16846-13114, Iran
| | - Farzaneh Feyzi
- Thermodynamics Research Laboratory, School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology (IUST), Tehran 16846-13114, Iran
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12
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Singh A, Doan LC, Lou D, Wen C, Vinh NQ. Interfacial Layers between Ion and Water Detected by Terahertz Spectroscopy. J Chem Phys 2022; 157:054501. [DOI: 10.1063/5.0095932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Dynamic fluctuations in hydrogen-bond network of water occur from femto- to nano-second timescale and provides insights into structural/dynamical aspects of water at ion-water interfaces. Employing terahertz spectroscopy assisted with molecular dynamics simulations, we study aqueous chloride solutions of five monovalent cations, namely, Li, Na, K, Rb and Cs. We show that ions modify the behavior of surrounding water molecules and form interfacial layers of water around them with physical properties distinct from that of bulk water. Small cations with high charge densities influence the kinetics of water well beyond the first solvation shell. At terahertz frequencies, we observe an emergence of fast relaxation processes of water with their magnitude following the ionic order Cs>Rb>K>Na>Li, revealing an enhanced population density of weakly coordinated water at ion-water interface. The results shed light on the structure breaking tendency of monovalent cations and provide insights into the properties of ionic solutions at the molecular level.
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Affiliation(s)
- Abhishek Singh
- Physics, Virginia Polytechnic Institute and State University, United States of America
| | - Luan C Doan
- Virginia Polytechnic Institute and State University, United States of America
| | - Djamila Lou
- Virginia Polytechnic Institute and State University, United States of America
| | - Chengyuan Wen
- Virginia Polytechnic Institute and State University - National Capital Region, United States of America
| | - Nguyen Q Vinh
- Department of Physics, Virginia Polytechnic Institute and State University, United States of America
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13
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He X, Zhang BX, Wang YF, Zhang YY, Yang YR, Wang XD, Lee DJ. Dynamic coalescence of two charged droplets with deflected angles in the presence of electric fields. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118812] [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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Kim T, Choi H, Choi H, Kim JS, Kim DH, Jeong U. Skin-inspired electrochemical tactility and luminescence. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.140259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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15
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Mo J, Wang C, Zeng J, Sha J, Li Z, Chen Y. Directional passive transport of nanodroplets on general axisymmetric surfaces. Phys Chem Chem Phys 2022; 24:9727-9734. [PMID: 35412533 DOI: 10.1039/d1cp05905j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Rapid removal of small-sized droplets passively using fixed structures is a key challenge for various applications including anti-icing, rapid cooling, and water harvesting. In this work, we investigate the directional motion of nanodroplets on axisymmetric surfaces with curvature gradient through molecular dynamics (MD) simulations. It is found that as the shape of the axisymmetric surface is changed from a dome to a trumpet, the droplet velocity is greatly enhanced, by a factor of ∼14. Such an increase is mainly caused by the increment in the driving force. The droplet velocity changes nonlinearly as the surface wettability is varied and assumes the maximum at the contact angle of ∼75°. We derive a formula for the driving force of nanodroplets on general axisymmetric surfaces by evaluating the pressure gradient inside the droplet induced by the curvature gradient. Molecular dynamics simulations are performed to directly measure the driving force and confirm that the theoretical formula works well. By illustrating the reduced initial velocity of droplets as a function of a dimensionless number, which represents the ratio of the driving force to the retentive force due to contact angle hysteresis, we show that the onset of droplet motion on axisymmetric surfaces occurs when the dimensionless number is above a critical value. The dimensionless number reveals the effects of surface geometry, surface wettability, and droplet size on the droplet motion.
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Affiliation(s)
- Jingwen Mo
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University, Nanjing 210096, P. R. China.
| | - Chen Wang
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University, Nanjing 210096, P. R. China.
| | - Jiaying Zeng
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University, Nanjing 210096, P. R. China.
| | - Jingjie Sha
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University, Nanjing 210096, P. R. China.
| | - Zhigang Li
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Yunfei Chen
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University, Nanjing 210096, P. R. China.
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16
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Villa AM, Doglia SM, De Gioia L, Natalello A, Bertini L. Fluorescence of KCl Aqueous Solution: A Possible Spectroscopic Signature of Nucleation. J Phys Chem B 2022; 126:2564-2572. [PMID: 35344657 PMCID: PMC8996234 DOI: 10.1021/acs.jpcb.2c01496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
![]()
Ion pairing
in water solutions alters both the water hydrogen-bond network and
ion solvation, modifying the dynamics and properties of electrolyte
water solutions. Here, we report an anomalous intrinsic fluorescence
of KCl aqueous solution at room temperature and show that its intensity
increases with the salt concentration. From the ab initio density
functional theory (DFT) and time-dependent DFT modeling, we propose
that the fluorescence emission could originate from the stiffening
of the hydrogen bond network in the hydration shell of solvated ion-pairs
that suppresses the fast nonradiative decay and allows the slower
radiative channel to become a possible decay pathway. Because computations
suggest that the fluorophores are the local ion-water structures present
in the prenucleation phase, this band could be the signature of the
incoming salt precipitation.
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Affiliation(s)
- Anna Maria Villa
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Silvia Maria Doglia
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Luca De Gioia
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Antonino Natalello
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Luca Bertini
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
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17
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Hu Z, Marti J. In Silico Drug Design of Benzothiadiazine Derivatives Interacting with Phospholipid Cell Membranes. MEMBRANES 2022; 12:membranes12030331. [PMID: 35323806 PMCID: PMC8949146 DOI: 10.3390/membranes12030331] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/09/2022] [Accepted: 03/15/2022] [Indexed: 12/21/2022]
Abstract
The use of drugs derived from benzothiadiazine, a bicyclic heterocyclic benzene derivative, has become a widespread treatment for diseases such as hypertension, low blood sugar or the human immunodeficiency virus, among others. In this work we have investigated the interactions of benzothiadiazine and four of its derivatives designed in silico with model zwitterionic cell membranes formed by dioleoylphosphatidylcholine, 1,2-dioleoyl-sn-glycero-3-phosphoserine and cholesterol at the liquid–crystal phase inside aqueous potassium chloride solution. We have elucidated the local structure of benzothiadiazine by means of microsecond molecular dynamics simulations of systems including a benzothiadiazine molecule or one of its derivatives. Such derivatives were obtained by the substitution of a single hydrogen site of benzothiadiazine by two different classes of chemical groups, one of them electron-donating groups (methyl and ethyl) and another one by electron-accepting groups (fluorine and trifluoromethyl). Our data have revealed that benzothiadiazine derivatives have a strong affinity to stay at the cell membrane interface although their solvation characteristics can vary significantly—they can be fully solvated by water in short periods of time or continuously attached to specific lipid sites during intervals of 10–70 ns. Furthermore, benzothiadiazines are able to bind lipids and cholesterol chains by means of single and double hydrogen-bonds of characteristic lengths between 1.6 and 2.1 Å.
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18
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Chatterjee S, Kumar I, Ghanta KC, Hens A, Biswas G. Insight into molecular rearrangement of a sessile ionic nanodroplet with applied electric field. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2021.117083] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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19
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Singh AK, Wen C, Cheng S, Vinh NQ. Long-range DNA-water interactions. Biophys J 2021; 120:4966-4979. [PMID: 34687717 DOI: 10.1016/j.bpj.2021.10.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 09/14/2021] [Accepted: 10/18/2021] [Indexed: 11/18/2022] Open
Abstract
DNA functions only in aqueous environments and adopts different conformations depending on the hydration level. The dynamics of hydration water and hydrated DNA leads to rotating and oscillating dipoles that, in turn, give rise to a strong megahertz to terahertz absorption. Investigating the impact of hydration on DNA dynamics and the spectral features of water molecules influenced by DNA, however, is extremely challenging because of the strong absorption of water in the megahertz to terahertz frequency range. In response, we have employed a high-precision megahertz to terahertz dielectric spectrometer, assisted by molecular dynamics simulations, to investigate the dynamics of water molecules within the hydration shells of DNA as well as the collective vibrational motions of hydrated DNA, which are vital to DNA conformation and functionality. Our results reveal that the dynamics of water molecules in a DNA solution is heterogeneous, exhibiting a hierarchy of four distinct relaxation times ranging from ∼8 ps to 1 ns, and the hydration structure of a DNA chain can extend to as far as ∼18 Å from its surface. The low-frequency collective vibrational modes of hydrated DNA have been identified and found to be sensitive to environmental conditions including temperature and hydration level. The results reveal critical information on hydrated DNA dynamics and DNA-water interfaces, which impact the biochemical functions and reactivity of DNA.
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Affiliation(s)
- Abhishek K Singh
- Department of Physics and Center for Soft Matter and Biological Physics, Blacksburg, Virginia
| | - Chengyuan Wen
- Department of Physics and Center for Soft Matter and Biological Physics, Blacksburg, Virginia
| | - Shengfeng Cheng
- Department of Physics and Center for Soft Matter and Biological Physics, Blacksburg, Virginia; Macromolecules Innovation Institute, Blacksburg, Virginia; Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia
| | - Nguyen Q Vinh
- Department of Physics and Center for Soft Matter and Biological Physics, Blacksburg, Virginia; Macromolecules Innovation Institute, Blacksburg, Virginia; Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia.
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20
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He X, Zhang BX, Wang SL, Wang YF, Yang YR, Wang XD, Lee DJ. Electrocoalescence of two charged nanodroplets under different types of external electric fields. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117417] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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21
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Hu Z, Martí J, Lu H. Structure of benzothiadiazine at zwitterionic phospholipid cell membranes. J Chem Phys 2021; 155:154303. [PMID: 34686044 DOI: 10.1063/5.0065163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The use of drugs derived from benzothiadiazine, which is a bicyclic heterocyclic benzene derivative, has become a widespread treatment for diseases such as hypertension (treated with diuretics such as bendroflumethiazide or chlorothiazide), low blood sugar (treated with non-diuretic diazoxide), or the human immunodeficiency virus, among others. In this work, we have investigated the interactions of benzothiadiazine with the basic components of cell membranes and solvents, such as phospholipids, cholesterol, ions, and water. The analysis of the mutual microscopic interactions is of central importance to elucidate the local structure of benzothiadiazine as well as the mechanisms responsible for the access of benzothiadiazine to the interior of the cell. We have performed molecular dynamics simulations of benzothiadiazine embedded in three different model zwitterionic bilayer membranes made by dimyristoylphosphatidylcholine, dioleoylphosphatidylcholine, 1,2-dioleoyl-sn-glycero-3-phosphoserine, and cholesterol inside aqueous sodium-chloride solution in order to systematically examine microscopic interactions of benzothiadiazine with the cell membrane at liquid-crystalline phase conditions. From data obtained through radial distribution functions, hydrogen-bonding lengths, and potentials of mean force based on reversible work calculations, we have observed that benzothiadiazine has a strong affinity to stay at the cell membrane interface although it can be fully solvated by water in short periods of time. Furthermore, benzothiadiazine is able to bind lipids and cholesterol chains by means of single and double hydrogen-bonds of different characteristic lengths.
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Affiliation(s)
- Zheyao Hu
- Department of Physics, Technical University of Catalonia-Barcelona Tech, B5-209 Northern Campus UPC, 08034 Barcelona, Catalonia, Spain
| | - Jordi Martí
- Department of Physics, Technical University of Catalonia-Barcelona Tech, B5-209 Northern Campus UPC, 08034 Barcelona, Catalonia, Spain
| | - Huixia Lu
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
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22
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23
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Saravi SH, Panagiotopoulos AZ. Individual Ion Activity Coefficients in Aqueous Electrolytes from Explicit-Water Molecular Dynamics Simulations. J Phys Chem B 2021; 125:8511-8521. [PMID: 34319101 DOI: 10.1021/acs.jpcb.1c04019] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We compute individual ion activity coefficients (IIACs) in aqueous NaCl, KCl, NaF, and KF solutions from explicit-water molecular dynamics simulations. Free energy changes are obtained from insertion of single ions-accompanied by uniform neutralizing backgrounds-into solution by gradually turning on first Lennard-Jones interactions, followed by Coulombic interactions using Ewald electrostatics. Simulations are performed at multiple system sizes, and all results are extrapolated to the thermodynamic limit, thus eliminating any possible artifacts from the neutralizing backgrounds. Because of controversies associated with measurements of IIACs from electrochemical cells with ion-selective electrodes, the reported experimental data are not widely accepted; thus there remains a knowledge gap with respect to the contributions of individual ions to solution nonidealities. Our results are in good qualitative agreement with these reported measurements, though significantly larger in magnitude. In particular, the relative positioning for the activity coefficients of anions and cations matches the experimental ordering for all four systems. This work establishes a robust thermodynamic framework, without a need to invoke extra hypotheses, that sheds light on the behavior of individual ions and their contributions to nonidealities of aqueous electrolyte solutions.
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Affiliation(s)
- Sina Hassanjani Saravi
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
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24
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Comparison of the effects of edge functionalized graphene oxide membranes on monovalent cation selectivity. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2020.118892] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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25
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Baghdasaryan Z, Babajanyan A, Odabashyan L, Lee JH, Friedman B, Lee K. Visualization of microwave near-field distribution in sodium chloride and glucose aqueous solutions by a thermo-elastic optical indicator microscope. Sci Rep 2021; 11:2589. [PMID: 33510224 PMCID: PMC7843988 DOI: 10.1038/s41598-020-80328-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 12/21/2020] [Indexed: 01/30/2023] Open
Abstract
In this study, a new optical method is presented to determine the concentrations of NaCl and glucose aqueous solutions by using a thermo-elastic optical indicator microscope. By measuring the microwave near-field distribution intensity, concentration changes of NaCl and glucose aqueous solutions were detected in the 0-100 mg/ml range, when exposed to microwave irradiation at 12 GHz frequency. Microwave near-field distribution intensity decreased as the NaCl or glucose concentration increased due to the changes of the absorption properties of aqueous solution. This method provides a novel approach for monitoring NaCl and glucose in biological liquids by using a CCD sensor capable of visualizing NaCl and glucose concentrations without scanning.
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Affiliation(s)
- Zhirayr Baghdasaryan
- Department of Physics, Sogang University, Seoul, 121-742, Korea
- Department of Radiophysics, Yerevan State University, 0025, Yerevan, Armenia
| | - Arsen Babajanyan
- Department of Radiophysics, Yerevan State University, 0025, Yerevan, Armenia
| | - Levon Odabashyan
- Department of Radiophysics, Yerevan State University, 0025, Yerevan, Armenia
| | - Jung-Ha Lee
- Department of Life Science, Sogang University, Seoul, 121-742, Korea
| | - Barry Friedman
- Department of Physics, Sam Houston State University, Huntsville, TX, 77341, USA
| | - Kiejin Lee
- Department of Physics, Sogang University, Seoul, 121-742, Korea.
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26
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27
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Marin TW, Janik I, Bartels DM, Chipman DM. Failure of molecular dynamics to provide appropriate structures for quantum mechanical description of the aqueous chloride ion charge-transfer-to-solvent ultraviolet spectrum. Phys Chem Chem Phys 2021; 23:9109-9120. [PMID: 33885094 DOI: 10.1039/d1cp00930c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The lowest band in the charge-transfer-to-solvent ultraviolet absorption spectrum of aqueous chloride ion is studied by experiment and computation. Interestingly, the experiments indicate that at concentrations up to at least 0.25 M, where calculations indicate ion pairing to be significant, there is no notable effect of ionic strength on the spectrum. The experimental spectra are fitted to aid comparison with computations. Classical molecular dynamic simulations are carried out on dilute aqueous Cl-, Na+, and NaCl, producing radial distribution functions in reasonable agreement with experiment and, for NaCl, clear evidence of ion pairing. Clusters are extracted from the simulations for quantum mechanical excited state calculations. Accurate ab initio coupled-cluster benchmark calculations on a small number of representative clusters are carried out and used to identify and validate an efficient protocol based on time-dependent density functional theory. The latter is used to carry out quantum mechanical calculations on thousands of clusters. The resulting computed spectrum is in excellent agreement with experiment for the peak position, with little influence from ion pairing, but is in qualitative disagreement on the width, being only about half as wide. It is concluded that simulation by classical molecular dynamics fails to provide an adequate variety of structures to explain the experimental CTTS spectrum of aqueous Cl-.
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Affiliation(s)
- Timothy W Marin
- Department of Physical Sciences, Benedictine University, 5700 College Rd, Lisle, IL 60532, USA
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28
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Mosallanejad S, Oluwoye I, Altarawneh M, Gore J, Dlugogorski BZ. Interfacial and bulk properties of concentrated solutions of ammonium nitrate. Phys Chem Chem Phys 2020; 22:27698-27712. [PMID: 33242055 DOI: 10.1039/d0cp04874g] [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
We conducted molecular dynamics (MD) simulations to calculate the density and surface tension of concentrated ammonium nitrate (AN) solutions up to the solubility limit of ammonium nitrate in water, by combining the SPC/E, SPCE/F and TIP4P/2005 water models with OPLS model for ammonium and nitrate ions. This is the first time that the properties of concentrated solutions of nitrates, especially AN, have been studied by molecular dynamics. We effectively account for the polarisation effects by the electronic continuum correction (ECC), practically realised via rescaling of the ionic charges. We found that, the full-charge force field MD simulations overestimate the experimental results, as the ions experience repulsion from the interface and prefer to remain in the subsurface layer and the bulk solution. In contrast, reducing the ionic charges results in the behaviour that fits well with the experimental data. The nitrate anions display a greater propensity for the interface than the ammonium cations. We accurately predict both the density and the rise in the surface tension of concentrated solutions of AN, recommending TIP4P/2005 for water and the scaled-charge OPLS model (OPLS/ECC) for the ions in the solutions. We observe that, the adsorption of anions to the interface accompanies their depletion in the subsurface layer, which is preferentially occupied by cations, resulting in the formation of the electric double layer. We demonstrate the ion deficiency for up to 3 Å below the surface and establish the requirement to include the polarisability effects in the OPLS model for AN. While these results confirmed the findings of the previous studies for dilute solutions, they are new in the solubility limit. Concentrated solutions exhibit a strong effect of the abundance of solute on the coordination numbers of ions and on the degree of ion pairing. Surprisingly, ion pairing decreases significantly at the interface compared with the bulk. The present study identifies OPLS/ECC, along with TIP4P/2005, to yield accurate predictions of physical properties of concentrated AN, with precision required for industrial applications, such as a formulation of emulsion and fuel-oil explosives that now predominate the civilian use of AN. An application of this model will allow one to predict the surface properties of supersaturated solutions of AN which fall outside the capability of the present laboratory experiments but are important industrially.
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Affiliation(s)
- Sara Mosallanejad
- Discipline of Chemistry and Physics, College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia
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29
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Hwang H, Cho YC, Lee S, Lee YH, Kim S, Kim Y, Jo W, Duchstein P, Zahn D, Lee GW. Hydration breaking and chemical ordering in a levitated NaCl solution droplet beyond the metastable zone width limit: evidence for the early stage of two-step nucleation. Chem Sci 2020; 12:179-187. [PMID: 34163588 PMCID: PMC8178806 DOI: 10.1039/d0sc04817h] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 11/30/2020] [Indexed: 11/25/2022] Open
Abstract
For over two decades, NaCl nucleation from a supersaturated aqueous solution has been predicted to occur via a two-step nucleation (TSN) mechanism, i.e., two sequential events, the formation of locally dense liquid regions followed by structural ordering. However, the formation of dense liquid regions in the very early stage of TSN has never been experimentally observed. By using a state-of-the-art technique, a combination of electrostatic levitation (ESL) and in situ synchrotron X-ray and Raman scatterings, we find experimental evidence that indicates the formation of dense liquid regions in NaCl bulk solution at an unprecedentedly high level of supersaturation (S = 2.31). As supersaturation increases, evolution of ion clusters leads to chemical ordering, but no topological ordering, which is a precursor for forming the dense disordered regions of ion clusters at the early stage of TSN. Moreover, as the ion clusters proceed to evolve under highly supersaturated conditions, we observe the breakage of the water hydration structure indicating the stability limit of the dense liquid regions, and thus leading to nucleation. The evolution of solute clusters and breakage of hydration in highly supersaturated NaCl bulk solution will provide new insights into the detailed mechanism of TSN for many other aqueous solutions.
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Affiliation(s)
- Hyerim Hwang
- Division of Industrial Metrology, Korea Research Institute of Standards and Science Daejeon 34113 Republic of Korea
| | - Yong Chan Cho
- Division of Industrial Metrology, Korea Research Institute of Standards and Science Daejeon 34113 Republic of Korea
| | - Sooheyong Lee
- Division of Industrial Metrology, Korea Research Institute of Standards and Science Daejeon 34113 Republic of Korea
- Department of Nano Science, University of Science and Technology Daejeon 34113 Republic of Korea
| | - Yun-Hee Lee
- Division of Industrial Metrology, Korea Research Institute of Standards and Science Daejeon 34113 Republic of Korea
- Department of Nano Science, University of Science and Technology Daejeon 34113 Republic of Korea
| | - Seongheun Kim
- Pohang Accelerator Laboratory, POSTECH Pohang 37673 Republic of Korea
| | - Yongjae Kim
- Division of Industrial Metrology, Korea Research Institute of Standards and Science Daejeon 34113 Republic of Korea
| | - Wonhyuk Jo
- Division of Industrial Metrology, Korea Research Institute of Standards and Science Daejeon 34113 Republic of Korea
| | - Patrick Duchstein
- Computer Chemistry Center, Friedrich-Alexander University of Erlangen-Nuremberg 91052 Erlangen Germany
| | - Dirk Zahn
- Computer Chemistry Center, Friedrich-Alexander University of Erlangen-Nuremberg 91052 Erlangen Germany
| | - Geun Woo Lee
- Division of Industrial Metrology, Korea Research Institute of Standards and Science Daejeon 34113 Republic of Korea
- Department of Nano Science, University of Science and Technology Daejeon 34113 Republic of Korea
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30
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Skarmoutsos I, Guardia E. Solvation structure and dynamics of the dimethylammonium cation diluted in liquid water: A molecular dynamics approach. J Chem Phys 2020; 152:234501. [PMID: 32571039 DOI: 10.1063/5.0004204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Classical molecular dynamics simulation techniques were employed to investigate the local solvation structure and related dynamics of the dimethylammonium cation diluted in liquid water at ambient conditions. The translational and orientational order around the dimethylammonium cation was investigated in terms of the corresponding radial and angular distribution functions. The results obtained revealed that the first solvation shell of the dimethylammonium consists mainly of two and, less frequently, three water molecules. The two nearest water neighbors form hydrogen bonds with the ammonium hydrogen atoms of the cation, whereas the third neighbor interacts with the methyl hydrogen atoms as well. The distribution of the trigonal order parameter exhibits a bimodal behavior, signifying the existence of local orientational heterogeneities in the solvation shell of the dimethylammonium cation. The calculated continuous and intermittent residence and hydrogen bond lifetimes for the cation-water pairs have also been found to be longer in comparison with the water-water ones. The very similar self-diffusion coefficients of the dimethylammonium cation and the water molecules in the bulk dilute solution indicate that the translational motions of the cation are mainly controlled by the translational mobility of the surrounding water molecules.
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Affiliation(s)
- Ioannis Skarmoutsos
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Vass. Constantinou 48, GR-116 35 Athens, Greece
| | - Elvira Guardia
- Departament de Física, Universitat Politècnica de Catalunya, Campus Nord-Edifici B4-B5, Jordi Girona 1-3, Barcelona E 08034, Spain
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31
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Shao Y, Shigenobu K, Watanabe M, Zhang C. Role of Viscosity in Deviations from the Nernst-Einstein Relation. J Phys Chem B 2020; 124:4774-4780. [PMID: 32412758 PMCID: PMC7497660 DOI: 10.1021/acs.jpcb.0c02544] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/05/2020] [Indexed: 11/30/2022]
Abstract
Deviations from the Nernst-Einstein relation are commonly attributed to ion-ion correlation and ion pairing. Despite the fact that these deviations can be quantified by either experimental measurements or molecular dynamics simulations, there is no rule of thumb to tell the extent of deviations. Here, we show that deviations from the Nernst-Einstein relation are proportional to the inverse viscosity by exploring the finite-size effect on transport properties under periodic boundary conditions. This conclusion is in accord with the established experimental results of ionic liquids.
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Affiliation(s)
- Yunqi Shao
- Department
of Chemistry-Ångström Laboratory, Uppsala University, Lägerhyddsvägen 1, P.O. Box 538, 75121 Uppsala, Sweden
| | - Keisuke Shigenobu
- Department
of Chemistry and Biotechnology, Yokohama
National University, Yokohama 240-8501, Japan
| | - Masayoshi Watanabe
- Department
of Chemistry and Biotechnology, Yokohama
National University, Yokohama 240-8501, Japan
| | - Chao Zhang
- Department
of Chemistry-Ångström Laboratory, Uppsala University, Lägerhyddsvägen 1, P.O. Box 538, 75121 Uppsala, Sweden
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32
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Abal JPK, Bordin JR, Barbosa MC. Salt parameterization can drastically affect the results from classical atomistic simulations of water desalination by MoS 2 nanopores. Phys Chem Chem Phys 2020; 22:11053-11061. [PMID: 32373906 DOI: 10.1039/d0cp00484g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Water scarcity is a reality in our world, and scenarios predicted by leading scientists in this area indicate that it will worsen in the next decades. However, new technologies based on low-cost seawater desalination can prevent the worst scenarios, providing fresh water for humanity. With this goal, membranes based on nanoporous materials have been suggested in recent years. One of the materials suggested is MoS2, and classical Molecular Dynamics (MD) simulation is one of the most powerful tools to explore these nanomaterials. However, distinct force fields employed in MD simulations are parameterized based on distinct experimental quantities. In this paper, we compare two models of salt that were built based on distinct properties of water-salt mixtures. One model fits the hydration free energy and lattice properties, and the second fits the crystal density and the density and the dielectric constant of water and salt mixtures. To compare the models, MD simulations for salty water flow through nanopores of two sizes were used - one pore big enough to accommodate hydrated ions, and one smaller in which the ion has to dehydrate to enter - and two rigid water models from the TIP4P family - TIP4P/2005 and TIP4P/ε. Our results indicate that the water permeability and salt rejection by the membrane are more influenced by the salt model than by the water model, especially for the narrow pore. In fact, completely distinct mechanisms were observed, and they are related to the characteristics employed in the ion model parameterization. The results show that not only can the water model influence the outcomes, but the ion model plays a crucial role when the pore is small enough.
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Affiliation(s)
- João P K Abal
- Institute of Physics, Federal University of Rio Grande do Sul, 91501-970, Porto Alegre, Brazil.
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Yamaoka S, Hyeon-Deuk K. Decelerated Liquid Dynamics Induced by Component-Dependent Supercooling in Hydrogen and Deuterium Quantum Mixtures. J Phys Chem Lett 2020; 11:4186-4192. [PMID: 32375000 DOI: 10.1021/acs.jpclett.0c00801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Isotopic mixtures of p-H2 and o-D2 molecules have been an attractive binary system because they include two kinds of purely isotopic molecules which possess the same electronic potential but the twice different mass inducing differently pronounced nuclear quantum effects (NQEs). Accessing details of structures and dynamics in such quantum mixtures combining complex molecular dynamics with NQEs of different strengths remains a challenging problem. Taking advantage of the nonempirical molecular dynamics method which describes p-H2 and o-D2 molecules, we found that the liquid dynamics slows down at a specific mixing ratio, which can be connected to the observed anomalous slowdown of crystallization in the quantum mixtures. We attributed the decelerated dynamics to the component-dependent supercooling of p-H2 taking place in the mixtures, demonstrating that there is an optimal mixing ratio to hinder crystallization. The obtained physical insights will help in experimentally controlling and achieving unknown quantum mixtures including superfluid.
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Affiliation(s)
- Shutaro Yamaoka
- Department of Chemistry, Kyoto University, Kyoto 606-8502, Japan
| | - Kim Hyeon-Deuk
- Department of Chemistry, Kyoto University, Kyoto 606-8502, Japan
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34
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Rimsza JM, Kuhlman KL. Surface Energies and Structure of Salt-Brine Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:2482-2491. [PMID: 32097016 DOI: 10.1021/acs.langmuir.9b03172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Permeability of salt formations is controlled by the equilibrium between the salt-brine and salt-salt interfaces described by the dihedral angle, which can change with the composition of the intergranular brine. Here, classical molecular dynamics (MD) simulations were used to investigate the structure and properties of the salt-brine interface to provide insight into the stability of salt systems. Mixed NaCl-KCl brines were investigated to explore differences in ion size on the surface energy and interface structure. Nonlinearity was noted in the salt-brine surface energy with increasing KCl concentration, and the addition of 10% KCl increased surface energies by 2-3 times (5.0 M systems). Size differences in Na+ and K+ ions altered the packing of dissolved ions and water molecules at the interface, impacting the surface energy. Additionally, ions at the interface had lower numbers of coordinating water molecules than those in the bulk and increased hydration for ions in systems with 100% NaCl or 100% KCl brines. Ultimately, small changes in brine composition away from pure NaCl altered the structure of the salt-brine interface, impacting the dihedral angle and the predicted equilibrium permeability of salt formations.
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Affiliation(s)
- Jessica M Rimsza
- Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico 87123, United States
| | - Kristopher L Kuhlman
- Applied Systems Analysis & Research, Sandia National Laboratories, Albuquerque, New Mexico 87123, United States
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35
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Ivanova AA, Cheremisin AN, Barifcani A, Iglauer S, Phan C. Molecular insights in the temperature effect on adsorption of cationic surfactants at liquid/liquid interfaces. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.112104] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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36
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Ahsan SAMS, Durani S, Reddy G, Subramanian Y. Shared hydrogen bonds: water in aluminated faujasite. Phys Chem Chem Phys 2020; 22:1632-1639. [PMID: 31894781 DOI: 10.1039/c9cp04972j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Water confined in faujasite, a zeolite, with aluminium content, exhibits properties different from those of bulk water as well as water confined in siliceous faujasite. The RDF between oxygen of water (OW) and oxygen of aluminium (OAl) shows a prominent first peak near to 2.9 Å similar to any oxygen-oxygen RDF seen in bulk water and unlike water confined in siliceous faujasite. Further, HW-OAl shows a peak near 1.9 Å suggesting hydrogen bonding between hydrogen of water and OAl. The water satisfies the hydrogen bond criteria with both O1Al and O2Al indicating that it is participating in a shared hydrogen bond. The hydrogen bond exchange between such a water forming a shared hydrogen bond to OAl and another water molecule H2Ob is investigated through the changes in the distances and appropriate angles. The O-Al-O angle of the zeolite increases by about 7 degrees on the formation of the shared hydrogen bond. The jump dynamics of the shared hydrogen bond when the two bonds break simultaneously has been obtained and this is reported. This jump reorientation dynamics is different compared to normal hydrogen bonding reported by Laage and Hynes: it has a short lifetime, around 50-100 fs computed from SHB(t). The intermittent and continuous hydrogen bond correlation functions are also reported.
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Affiliation(s)
- S A M Shamimul Ahsan
- Atomic Mineral Directorate For Exploration & Research, Nagarbhavi, Bangalore-560072, India
| | - Smeer Durani
- Atomic Mineral Directorate For Exploration & Research, R. K. Puram, New Delhi-110066, India
| | - Govardhan Reddy
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012, India.
| | - Yashonath Subramanian
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012, India.
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37
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Shao Y, Hellström M, Yllö A, Mindemark J, Hermansson K, Behler J, Zhang C. Temperature effects on the ionic conductivity in concentrated alkaline electrolyte solutions. Phys Chem Chem Phys 2020; 22:10426-10430. [PMID: 31895378 DOI: 10.1039/c9cp06479f] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alkaline electrolyte solutions are important components in rechargeable batteries and alkaline fuel cells. As the ionic conductivity is thought to be a limiting factor in the performance of these devices, which are often operated at elevated temperatures, its temperature dependence is of significant interest. Here we use NaOH as a prototypical example of alkaline electrolytes, and for this system we have carried out reactive molecular dynamics simulations with an experimentally verified high-dimensional neural network potential derived from density-functional theory calculations. It is found that in concentrated NaOH solutions elevated temperatures enhance both the contributions of proton transfer to the ionic conductivity and deviations from the Nernst-Einstein relation. These findings are expected to be of practical relevance for electrochemical devices based on alkaline electrolyte solutions.
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Affiliation(s)
- Yunqi Shao
- Department of Chemistry -Ångström Laboratory, Uppsala University, Box 538, 751 21 Uppsala, Sweden.
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38
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Seal S, Doblhoff-Dier K, Meyer J. Dielectric Decrement for Aqueous NaCl Solutions: Effect of Ionic Charge Scaling in Nonpolarizable Water Force Fields. J Phys Chem B 2019; 123:9912-9921. [PMID: 31647235 PMCID: PMC6875873 DOI: 10.1021/acs.jpcb.9b07916] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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We investigate the dielectric constant and the dielectric decrement of aqueous NaCl
solutions by means of molecular dynamic simulations. We thereby compare the performance
of four different force fields and focus on disentangling the origin of the dielectric
decrement and the influence of scaled ionic charges, as often used in nonpolarizable
force fields to account for the missing dynamic polarizability in the shielding of
electrostatic ion interactions. Three of the force fields showed excessive contact ion
pair formation, which correlates with a reduced dielectric decrement. In spite of the
fact that the scaling of charges only weakly influenced the average polarization of
water molecules around an ion, the rescaling of ionic charges did influence the
dielectric decrement, and a close-to-linear relation of the slope of the dielectric
constant as a function of concentration with the ionic charge was found.
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Affiliation(s)
- Sayan Seal
- Gorlaeus Laboratories, Leiden Institute of Chemistry , Leiden University , PO Box 9502, 2300 RA Leiden , The Netherlands
| | - Katharina Doblhoff-Dier
- Gorlaeus Laboratories, Leiden Institute of Chemistry , Leiden University , PO Box 9502, 2300 RA Leiden , The Netherlands
| | - Jörg Meyer
- Gorlaeus Laboratories, Leiden Institute of Chemistry , Leiden University , PO Box 9502, 2300 RA Leiden , The Netherlands
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39
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Teychené J, Balmann HRD, Maron L, Galier S. Investigation of ions hydration using molecular modeling. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111394] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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40
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Druchok M, Lukšič M. Carboxylated carbon nanotubes can serve as pathways for molecules in sandwich-like two-phase organic-water systems. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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41
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Laurinavichyute VK, Shermukhamedov SA, Peshkova MA, Nazmutdinov RR, Tsirlina GA. Electrolyte in heterogeneous water-glucose mixtures: A view from experiment and molecular modeling. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2019.110440] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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42
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43
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Chen Q, Ma J, Xu H, Zhang Y. The impact of the ionic concentration on electrocoalescence of the nanodroplet driven by dielectrophoresis. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111214] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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44
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Zhou Y, Dong H, Yang Z, Liu Y. Break-up behavior of droplets containing chlorine salt with the same valence cation under electric field via molecular dynamics simulation. J DISPER SCI TECHNOL 2019. [DOI: 10.1080/01932691.2019.1650756] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Yu Zhou
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao, China
| | - Hang Dong
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao, China
| | - Zhuojun Yang
- College of Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Yonghong Liu
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao, China
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45
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Yllö A, Zhang C. Experimental and molecular dynamics study of the ionic conductivity in aqueous LiCl electrolytes. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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46
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Dong H, Liu Y, Zhou Y, Liu T, Li M, Yang Z. Mechanism investigation of coalescence behaviors of conducting droplets by molecular dynamics simulations. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.03.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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47
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Zhou Y, Dong H, Liu YH, Yang ZJ, Liu T, Li M. Molecular Dynamics Simulations of the Electrocoalescence Behaviors of Two Unequally Sized Conducting Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:6578-6584. [PMID: 31045371 DOI: 10.1021/acs.langmuir.9b00744] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The electrocoalescence of droplets plays a crucial role in various fields. However, studies on the effects of droplet radius on the electrocoalescence behaviors of droplets have not been conducted until now. In this work, the electrocoalescence behaviors of two unequally sized conducting droplets are investigated via molecular dynamics (MD) simulations. The influences of electric field strength and droplet radius on the electrocoalescence behaviors of two unequally sized droplets are investigated. When the electric field strength increases, the contact cone angle between the droplets increases, and the two droplets are more likely to partially coalesce and bounce. When the radius of the smaller droplet between the two droplets increases at the same electric field strength, the contact cone angle, daughter droplet size, and ions in the daughter droplet increase, whereas the critical electric field strength ( Ed) for generating the daughter droplet decreases. Furthermore, the daughter droplet is ejected from the smaller droplet when the two droplets have different radii.
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48
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Moosavi S, Rayhani M, Malayeri M, Riazi M. Impact of monovalent and divalent cationic and anionic ions on wettability alteration of dolomite rocks. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.02.078] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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49
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Mo J, Sha J, Li D, Li Z, Chen Y. Fluid release pressure for nanochannels: the Young-Laplace equation using the effective contact angle. NANOSCALE 2019; 11:8408-8415. [PMID: 30985837 DOI: 10.1039/c8nr08987f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Releasing fluids from nanochannels is quite challenging, yet crucial for the application of nanofluidic systems, e.g. drug delivery and nanoprinting. Previous work suggests that the pressure required to activate the releasing is enormously high (50 to above 300 MPa), while its underlying mechanism still remains unclear. In this work, through molecular dynamics simulations, we have identified a critical tilt angle of the hydrophilic nanochannel, below which spontaneous release of water is achieved. A significant increase in the contact angle is observed during the fluid releasing process due to the transition from the solid fluid contact to the fluid vapor contact. Such transition in nanoscale channels can significantly raise the release pressure by at most ∼30 MPa depending on the channel height and surface property, which makes the classical Young-Laplace equation underestimate the release pressure. By incorporating the derived formula for the largest effective contact angle, a modified Young-Laplace equation is developed, which predicts the release pressure well for both hydrophobic and hydrophilic channels down to the nanoscale. Furthermore, it is discovered that for nanoscale channels, the decreased rate of the normalized release pressure as a function of the contact angle becomes fast when the surface energy of the channel grows strong. The fast decreased rate is mainly caused by the adsorption of water molecules at the exit when the surface becomes highly hydrophilic.
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Affiliation(s)
- Jingwen Mo
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University, Nanjing 210096, P.R. China.
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50
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France-Lanord A, Grossman JC. Correlations from Ion Pairing and the Nernst-Einstein Equation. PHYSICAL REVIEW LETTERS 2019; 122:136001. [PMID: 31012622 DOI: 10.1103/physrevlett.122.136001] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Indexed: 05/21/2023]
Abstract
We present a new approximation to ionic conductivity well suited to dynamical atomic-scale simulations, based on the Nernst-Einstein equation. In our approximation, ionic aggregates constitute the elementary charge carriers, and are considered as noninteracting species. This approach conveniently captures the dominant effect of ion-ion correlations on conductivity, short range interactions in the form of clustering. In addition to providing better estimates to the conductivity at a lower computational cost than exact approaches, this new method allows us to understand the physical mechanisms driving ion conduction in concentrated electrolytes. As an example, we consider Li^{+} conduction in poly(ethylene oxide), a standard solid-state polymer electrolyte. Using our newly developed approach, we are able to reproduce recent experimental results reporting negative cation transference numbers at high salt concentrations, and to confirm that this effect can be caused by a large population of negatively charged clusters involving cations.
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Affiliation(s)
- Arthur France-Lanord
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Jeffrey C Grossman
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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