1
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Ogrin P, Urbic T. Simple rose model of water in constant electric field. Phys Rev E 2023; 107:054801. [PMID: 37329104 DOI: 10.1103/physreve.107.054801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 04/12/2023] [Indexed: 06/18/2023]
Abstract
A simple two-dimensional statistical mechanical water model, called the rose model, was used in this work. We studied how a homogeneous constant electric field affects the properties of water. The rose model is a very simple model that helps explain the anomalous properties of water. Rose water molecules are represented as two-dimensional Lennard-Jones disks with potentials for orientation-dependent pairwise interactions mimicking formations of hydrogen bonds. The original model is modified by addition of charges for interaction with the electric field. We studied what kind of influence the electric field strength has on the model's properties. To determine the structure and thermodynamics of the rose model under the influence of the electric field we used Monte Carlo simulations. Under the influence of a weak electric field the anomalous properties and phase transitions of the water do not change. On the other hand, the strong fields shift the phase transition points as well as the position of the density maximum.
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Affiliation(s)
- Peter Ogrin
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Vecna Pot 113, SI-1000 Ljubljana, Slovenia
| | - Tomaz Urbic
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Vecna Pot 113, SI-1000 Ljubljana, Slovenia
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2
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Functionalized boron nitride nanosheet as a membrane for removal of Pb2+ and Cd2+ ions from aqueous solution. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114920] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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3
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Assegehegn G, Brito-de la Fuente E, Franco JM, Gallegos C. The Importance of Understanding the Freezing Step and Its Impact on Freeze-Drying Process Performance. J Pharm Sci 2019; 108:1378-1395. [DOI: 10.1016/j.xphs.2018.11.039] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 11/24/2018] [Accepted: 11/27/2018] [Indexed: 01/01/2023]
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4
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Li B, Gu Y, Chen M. Cavitation inception of water with solid nanoparticles: A molecular dynamics study. ULTRASONICS SONOCHEMISTRY 2019; 51:120-128. [PMID: 30420302 DOI: 10.1016/j.ultsonch.2018.10.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 10/28/2018] [Accepted: 10/29/2018] [Indexed: 05/24/2023]
Abstract
Cavitation in liquid with impurities is important in heterogeneous nucleation applications. One of the most widely existing kinds of impurities is solid particles, which can be found in natural water from rivers and specially prepared water such as nanofluids. Understanding the effects caused by the existence of nanoparticles on cavitation in water is vital to the rapidly developed nanotechnologies and medical researches. In this study, cavitation in water with nanoparticles is investigated through molecular dynamics simulations. The effects by nanoparticle materials and sizes on cavitation are discussed by using SiO2 and polyethylene spherical nanoparticles with different diameters. The nucleation rate and the formation of critical bubbles in cavitation are studied via the Voronoi tessellation and the mean first passage time methods. The hydrogen bond network in water is also analyzed. Results reveal that SiO2 and polyethylene nanoparticles may destabilize the hydrogen bond network in water. With the same particle size, cavitation in water with polyethylene nanoparticles is promoted to a greater extent than that with SiO2 nanoparticles. With the same nanoparticle material, cavitation is promoted with the increase in particle size in a range spanning half to ten times the critical bubble radius. Beyond this range, particle size has little influence on cavitation. Reasons for those effects on cavitation due to the presence of solid nanoparticles are discussed by analysing the changes of hydrogen bonds network in water.
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Affiliation(s)
- Buxuan Li
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Youwei Gu
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Min Chen
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.
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5
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Alternative Methods of Controlling Nucleation in Freeze Drying. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2019. [DOI: 10.1007/978-1-4939-8928-7_4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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6
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Wu L, Han Y, Zhang Q, Zhao S. Effect of external electric field on nanobubbles at the surface of hydrophobic particles during air flotation. RSC Adv 2019; 9:1792-1798. [PMID: 35516131 PMCID: PMC9059776 DOI: 10.1039/c8ra08935c] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 01/02/2019] [Indexed: 12/11/2022] Open
Abstract
In this paper, the effect of external electric field on nanobubbles adsorbed on the surface of hydrophobic particles during air flotation was studied by molecular dynamics simulations. The gas density distribution, diffusion coefficient, viscosity, and the change of the angle and number distribution of hydrogen bonds in the system with different amounts of gas molecules were calculated and compared with the results without an external electric field. The results show that the external electric field can make the size of the bubbles smaller. The diffusion coefficient of the gas increases and the viscosity of the system decreases when the external electric field is applied, which contribute to the reduction of the size of the nanobubbles. At the same time, comparing with the results under no external electric field, the angle of hydrogen bonding under the external electric field will increase, and the proportion of water molecules containing more hydrogen bonds will reduce, which further explains the reason why the external electric field reduces the viscosity. The conclusions of this paper demonstrate at the micro level that the external electric field can enhance the efficiency of air-floating technology for the separation of hydrophobic particles, which may provide meaningful theoretical guidance for the application and optimization of electric field-enhanced air-floating technology in practice. In this paper, the effect of external electric field on nanobubbles adsorbed on the surface of hydrophobic particles during air flotation was studied by molecular dynamics simulations.![]()
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Affiliation(s)
- Leichao Wu
- Measurement Technology and Instrumentation Key Laboratory of Hebei Province
- School of Electrical Engineering
- Yanshan University
- Qinhuangdao 066004
- P. R. China
| | - Yong Han
- Measurement Technology and Instrumentation Key Laboratory of Hebei Province
- School of Electrical Engineering
- Yanshan University
- Qinhuangdao 066004
- P. R. China
| | - Qianrui Zhang
- Measurement Technology and Instrumentation Key Laboratory of Hebei Province
- School of Electrical Engineering
- Yanshan University
- Qinhuangdao 066004
- P. R. China
| | - Shuai Zhao
- Measurement Technology and Instrumentation Key Laboratory of Hebei Province
- School of Electrical Engineering
- Yanshan University
- Qinhuangdao 066004
- P. R. China
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7
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Zhou Y, Li B, Gu Y, Chen M. A molecular dynamics simulation study on the cavitation inception of water with dissolved gases. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1559371] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Yusi Zhou
- Department of Engineering Mechanics, Center for Nano and Micro Mechanics, Tsinghua University, Beijing, People’s Republic of China
| | - Buxuan Li
- Department of Engineering Mechanics, Center for Nano and Micro Mechanics, Tsinghua University, Beijing, People’s Republic of China
| | - Youwei Gu
- Department of Engineering Mechanics, Center for Nano and Micro Mechanics, Tsinghua University, Beijing, People’s Republic of China
| | - Min Chen
- Department of Engineering Mechanics, Center for Nano and Micro Mechanics, Tsinghua University, Beijing, People’s Republic of China
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8
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Zhu L, Han Y. Influence of alternating electric fields and impurity Mg2+ on CaCl2 aqueous solution: A study by molecular dynamics simulation. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.09.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Wu L, Han Y, Zhang Q, Zhu L, Zhang C, Zhao R. Molecular Dynamics Simulation: Influence of External Electric Field on Bubble Interface in Air Flotation Process. Chem Res Chin Univ 2018. [DOI: 10.1007/s40242-018-8195-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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10
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Kahk JM, Tan BH, Ohl CD, Loh ND. Viscous field-aligned water exhibits cubic-ice-like structural motifs. Phys Chem Chem Phys 2018; 20:19877-19884. [PMID: 29968884 DOI: 10.1039/c8cp02697a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Strong electric fields are known to greatly accelerate the freezing of water in molecular dynamics simulations, and have also been shown to affect the thermodynamics of the phase transition. In this work, a mechanistic explanation for field-induced crystallization of water is presented. Due to the coupling between the rotational and the translational degrees of freedom of individual water molecules, an applied field can directly drive the formation of cubic-ice like local motifs in water. Analysis of the angular distributions of water molecules in TIP4P-2005 water at field strengths between 0.0 and 0.32 V Å-1 demonstrates the existence of such motifs in the field-aligned liquid phase that is observed prior to the onset of the freezing transition. The dynamic properties of this field-aligned liquid phase are also studied, and its viscosity is shown to be within a factor of two of that of regular liquid water using the Green-Kubo method as well as mean squared displacements. The choice between the NPT and the NVT ensembles is shown to have a strong impact on the evolution of molecular dynamics trajectories at field strengths close to the threshold for the freezing transition, and the importance of properly accounting for the electric field terms in the pressure virial is emphasized.
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Affiliation(s)
- J Matthias Kahk
- Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore
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11
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Zaragoza A, Espinosa JR, Ramos R, Antonio Cobos J, Luis Aragones J, Vega C, Sanz E, Ramírez J, Valeriani C. Phase boundaries, nucleation rates and speed of crystal growth of the water-to-ice transition under an electric field: a simulation study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:174002. [PMID: 29508769 DOI: 10.1088/1361-648x/aab464] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We investigate with computer simulations the effect of applying an electric field on the water-to-ice transition. We use a combination of state-of-the-art simulation techniques to obtain phase boundaries and crystal growth rates (direct coexistence), nucleation rates (seeding) and interfacial free energies (seeding and mold integration). First, we consider ice Ih, the most stable polymorph in the absence of a field. Its normal melting temperature, speed of crystal growth and nucleation rate (for a given supercooling) diminish as the intensity of the field goes up. Then, we study polarised cubic ice, or ice Icf, the most stable solid phase under a strong electric field. Its normal melting point goes up with the field and, for a given supercooling, under the studied field (0.3 V nm-1) ice Icf nucleates and grows at a similar rate as Ih with no field. The net effect of the field would then be that ice nucleates at warmer temperatures, but in the form of ice Icf. The main conclusion of this work is that reasonable electric fields (not strong enough to break water molecules apart) are not relevant in the context of homogeneous ice nucleation at 1 bar.
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Affiliation(s)
- Alberto Zaragoza
- Departamento de Estructura de la Materia, Fisica Termica y Electronica, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, 28040 Madrid, Spain. Departamento de Ingenieria Fisica, Division de Ciencias e Ingenierias, Universidad de Guanajuato, Loma del Bosque 103, Col. Lomas del Campestre, CP 37150 Leon, Mexico
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12
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Zhu L, Han Y, Zhang C, Zhao R, Tang S. Molecular dynamics simulation for the impact of an electrostatic field and impurity Mg2+ions on hard water. RSC Adv 2017. [DOI: 10.1039/c7ra09715h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
A detailed analysis of the structural parameters and dynamic parameters of hard water solutions under an external electrostatic field was performed by molecular dynamics (MD) simulations with the presence of impurity Mg2+ions.
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Affiliation(s)
- Lin Zhu
- Measurement Technology and Instrumentation Key Laboratory of Hebei Province
- School of Electrical Engineering
- Yanshan University
- Qinhuangdao 066004
- P. R. China
| | - Yong Han
- Measurement Technology and Instrumentation Key Laboratory of Hebei Province
- School of Electrical Engineering
- Yanshan University
- Qinhuangdao 066004
- P. R. China
| | - Chuanxin Zhang
- Measurement Technology and Instrumentation Key Laboratory of Hebei Province
- School of Electrical Engineering
- Yanshan University
- Qinhuangdao 066004
- P. R. China
| | - Ruikuan Zhao
- Measurement Technology and Instrumentation Key Laboratory of Hebei Province
- School of Electrical Engineering
- Yanshan University
- Qinhuangdao 066004
- P. R. China
| | - Shoufeng Tang
- School of Environmental and Chemical Engineering
- Yanshan University
- Qinhuangdao 066004
- P. R. China
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13
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Desgranges C, Delhommelle J. Evaluation of the grand-canonical partition function using expanded Wang-Landau simulations. V. Impact of an electric field on the thermodynamic properties and ideality contours of water. J Chem Phys 2016; 145:184504. [DOI: 10.1063/1.4967336] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Caroline Desgranges
- Department of Chemistry, University of North Dakota, 151 Cornell Street Stop 9024, Grand Forks, North Dakota 58202, USA
| | - Jerome Delhommelle
- Department of Chemistry, University of North Dakota, 151 Cornell Street Stop 9024, Grand Forks, North Dakota 58202, USA
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14
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Zong D, Hu H, Duan Y, Sun Y. Viscosity of Water under Electric Field: Anisotropy Induced by Redistribution of Hydrogen Bonds. J Phys Chem B 2016; 120:4818-27. [DOI: 10.1021/acs.jpcb.6b01686] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Diyuan Zong
- Department
of Thermal Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Han Hu
- Department
of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Yuanyuan Duan
- Department
of Thermal Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Ying Sun
- Department
of Thermal Engineering, Tsinghua University, Beijing 100084, P. R. China
- Department
of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, Pennsylvania 19104, United States
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15
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Calvo F, Falvo C, Parneix P. Atomistic Modeling of Vibrational Action Spectra in Polyatomic Molecules: Nuclear Quantum Effects. J Phys Chem A 2014; 118:5427-36. [DOI: 10.1021/jp5040147] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- F. Calvo
- ILM, Université Lyon I and CNRS UMR 5306, 43 Bd du 11 Novembre 1918, F69622 Villeurbanne Cedex, France
| | - C. Falvo
- Institut des Sciences
Moléculaires d’Orsay, UMR CNRS 8214, Université Paris Sud 11, Bât.
210, F91405 Orsay Cedex, France
| | - P. Parneix
- Institut des Sciences
Moléculaires d’Orsay, UMR CNRS 8214, Université Paris Sud 11, Bât.
210, F91405 Orsay Cedex, France
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16
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Saitta AM, Saija F, Giaquinta PV. Ab initio molecular dynamics study of dissociation of water under an electric field. PHYSICAL REVIEW LETTERS 2012; 108:207801. [PMID: 23003187 DOI: 10.1103/physrevlett.108.207801] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Indexed: 05/24/2023]
Abstract
The behavior of liquid water under an electric field is a crucial phenomenon in science and engineering. However, its detailed description at a microscopic level is difficult to achieve experimentally. Here we report on the first ab initio molecular-dynamics study on water under an electric field. We observe that the hydrogen-bond length and the molecular orientation are significantly modified at low-to-moderate field intensities. Fields beyond a threshold of about 0.35 V/Å are able to dissociate molecules and sustain an ionic current via a series of correlated proton jumps. Upon applying even more intense fields (∼1.0 V/Å), a 15%-20% fraction of molecules are instantaneously dissociated and the resulting ionic flow yields a conductance of about 7.8 Ω-1 cm-1, in good agreement with experimental values. This result paves the way to quantum-accurate microscopic studies of the effect of electric fields on aqueous solutions and, thus, to massive applications of ab initio molecular dynamics in neurobiology, electrochemistry, and hydrogen economy.
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Affiliation(s)
- A Marco Saitta
- IMPMC, CNRS-UMR 7590, Université P & M Curie, 75252 Paris, France.
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17
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Zhao Y, Dong K, Liu X, Zhang S, Zhu J, Wang J. Structure of ionic liquids under external electric field: a molecular dynamics simulation. MOLECULAR SIMULATION 2012. [DOI: 10.1080/08927022.2011.610894] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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18
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Murad S. The role of external electric fields in enhancing ion mobility, drift velocity, and drift–diffusion rates in aqueous electrolyte solutions. J Chem Phys 2011; 134:114504. [DOI: 10.1063/1.3565478] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Maerzke KA, Siepmann JI. Effects of an Applied Electric Field on the Vapor−Liquid Equilibria of Water, Methanol, and Dimethyl Ether. J Phys Chem B 2010; 114:4261-70. [DOI: 10.1021/jp9101477] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Katie A. Maerzke
- Departments of Chemistry and of Chemical Engineering and Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455
| | - J. Ilja Siepmann
- Departments of Chemistry and of Chemical Engineering and Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455
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20
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Shevkunov SV. Charge separation in water molecule clusters under thermal fluctuations: 1. Intermolecular interactions. COLLOID JOURNAL 2008. [DOI: 10.1134/s1061933x08050141] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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21
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Calvo F, Dugourd P. Folding of gas-phase polyalanines in a static electric field: alignment, deformations, and polarization effects. Biophys J 2008; 95:18-32. [PMID: 18223004 PMCID: PMC2426642 DOI: 10.1529/biophysj.107.124685] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Accepted: 12/28/2007] [Indexed: 11/18/2022] Open
Abstract
Monte Carlo simulations of the temperature-induced unfolding of small gas-phase polyalanines in a static, homogeneous electric field are reported, based on the AMBER ff96 force field. The peptides exhibit a structural transition from the native alpha-helix state to entropically favored beta-sheet conformations, before eventually turning to extended coil at higher temperatures. Upon switching the electric field, the molecules undergo preferential alignment of their dipole moment vector toward the field axis and a shift of the alpha-beta transition to higher temperatures. At higher field strengths (>10(8) V/m) the molecules stretch and the alpha-beta and beta-coil transitions merge. A simple three-state model is shown to account for the observed behavior. Under even higher fields, density functional theory calculations and a polarizable force field both show that electronic rearrangements tend to further increase the dipole moment, polarization effects being approximately half in magnitude with respect to stretching effect. Finally a tentative (temperature, field-strength) phase diagram is sketched.
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Affiliation(s)
- F Calvo
- Centre National de la Recherche Scientifique, Laboratoire de Spectrometrie Ionique et Moleculaire, Université de Lyon, Université Lyon 1, Villeurbanne, France.
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22
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Rai D, Kulkarni AD, Gejji SP, Pathak RK. Water clusters (H2O)n, n=6–8, in external electric fields. J Chem Phys 2008; 128:034310. [DOI: 10.1063/1.2816565] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Petersen A, Schneider H, Rau G, Glasmacher B. A new approach for freezing of aqueous solutions under active control of the nucleation temperature. Cryobiology 2006; 53:248-57. [PMID: 16887112 DOI: 10.1016/j.cryobiol.2006.06.005] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2006] [Revised: 06/05/2006] [Accepted: 06/19/2006] [Indexed: 11/17/2022]
Abstract
An experimental setup for controlled freezing of aqueous solutions is introduced. The special feature is a mechanism to actively control the nucleation temperature via electrofreezing: an ice nucleus generated at a platinum electrode by the application of an electric high voltage pulse initiates the crystallization of the sample. Using electrofreezing, the nucleation temperature in pure water can be precisely adjusted to a desired value over the whole temperature range between a maximum temperature Tn(max) close to the melting point and the temperature of spontaneous nucleation. However, the presence of additives can inhibit the nucleus formation. The influence of hydroxyethylstarch (HES), glucose, glycerol, additives commonly used in cryobiology, and NaCl on Tn(max) were investigated. While the decrease showed to be moderate for the non-ionic additives, the hindrance of nucleation by ionic NaCl makes the direct application of electrofreezing in solutions with physiological salt concentrations impossible. Therefore, in the multi-sample freezing device presented in this paper, the ice nucleus is produced in a separate volume of pure water inside an electrode cap. This way, the nucleus formation becomes independent of the sample composition. Using electrofreezing rather than conventional seeding methods allows automated freezing of many samples under equal conditions. Experiments performed with model solutions show the reliability and repeatability of this method to start crystallization in the test samples at different specified temperatures. The setup was designed to freeze samples of small volume for basic investigations in the field of cryopreservation and freeze-drying, but the mode of operation might be interesting for many other applications where a controlled nucleation of aqueous solutions is of importance.
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Affiliation(s)
- Ansgar Petersen
- Helmholtz-Institute for Biomedical Engineering, Department of Cryobiology & Biomaterials, RWTH Aachen University, 52074 Aachen, Germany.
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