1
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Becker M, Loche P, Rezaei M, Wolde-Kidan A, Uematsu Y, Netz RR, Bonthuis DJ. Multiscale Modeling of Aqueous Electric Double Layers. Chem Rev 2024; 124:1-26. [PMID: 38118062 PMCID: PMC10785765 DOI: 10.1021/acs.chemrev.3c00307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 11/17/2023] [Accepted: 11/30/2023] [Indexed: 12/22/2023]
Abstract
From the stability of colloidal suspensions to the charging of electrodes, electric double layers play a pivotal role in aqueous systems. The interactions between interfaces, water molecules, ions and other solutes making up the electrical double layer span length scales from Ångströms to micrometers and are notoriously complex. Therefore, explaining experimental observations in terms of the double layer's molecular structure has been a long-standing challenge in physical chemistry, yet recent advances in simulations techniques and computational power have led to tremendous progress. In particular, the past decades have seen the development of a multiscale theoretical framework based on the combination of quantum density functional theory, force-field based simulations and continuum theory. In this Review, we discuss these theoretical developments and make quantitative comparisons to experimental results from, among other techniques, sum-frequency generation, atomic-force microscopy, and electrokinetics. Starting from the vapor/water interface, we treat a range of qualitatively different types of surfaces, varying from soft to solid, from hydrophilic to hydrophobic, and from charged to uncharged.
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Affiliation(s)
| | - Philip Loche
- Fachbereich
Physik, Freie Universität Berlin, 14195 Berlin, Germany
- Laboratory
of Computational Science and Modeling, IMX, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Majid Rezaei
- Fachbereich
Physik, Freie Universität Berlin, 14195 Berlin, Germany
- Institute
of Theoretical Chemistry, Ulm University, 89081 Ulm, Germany
| | | | - Yuki Uematsu
- Department
of Physics and Information Technology, Kyushu
Institute of Technology, 820-8502 Iizuka, Japan
- PRESTO,
Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Roland R. Netz
- Fachbereich
Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Douwe Jan Bonthuis
- Institute
of Theoretical and Computational Physics, Graz University of Technology, 8010 Graz, Austria
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2
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Leung K. Finding Infinities in Nanoconfined Geothermal Electrolyte Static Dielectric Properties and Implications on Ion Adsorption/Pairing. NANO LETTERS 2023; 23:8868-8874. [PMID: 37531607 DOI: 10.1021/acs.nanolett.3c01865] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2023]
Abstract
Infinities should naturally occur in the dielectric responses of ionic solutions relevant to many geochemical, energy storage, and electrochemical applications at a strictly zero frequency. Using molecular dynamics simulations cross-referenced with coarse-grained Monte Carlo models, using nanoslit pore models at hydrothermal conditions, and treating confined mobile charges as polarization, we demonstrate the far reaching consequences. The dielectric permittivity profile perpendicular to the slit (ϵ⊥(z)) increases, not decreases, with ionic concentration, unlike in the more widely studied megahertz-to-gigahertz frequency range. In confined electrolytes, the divergences in ϵ⊥(z) correctly describe crossovers between bulk- and surface-dominated dielectric behavior. Nanoconfinement at low ionic concentrations changes monovalent ion energetics by 1-2 kJ/mol, but no dielectric property studied so far is universally correlated to ion adsorption or ion-ion interactions. We caution that infinities signal violation of the "electrical insulator" dielectric assumption.
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Affiliation(s)
- Kevin Leung
- Sandia National Laboratories, MS 0750, Albuquerque, New Mexico 87185, United States of America
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3
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Das B, Ruiz-Barragan S, Marx D. Deciphering the Properties of Nanoconfined Aqueous Solutions by Vibrational Sum Frequency Generation Spectroscopy. J Phys Chem Lett 2023; 14:1208-1213. [PMID: 36716226 PMCID: PMC9923734 DOI: 10.1021/acs.jpclett.2c03409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/21/2022] [Indexed: 06/18/2023]
Abstract
When confined between walls at nanometer distances, water exhibits surprisingly different properties with reference to bare interfacial water. Based on computer simulations, we demonstrate how vibrational sum frequency generation (VSFG) spectroscopy can be used-even with very mild symmetry breaking-to discriminate multilayer water in wide slit pores from both bilayer and monolayer water confined within molecularly narrow pores. Applying the technique, the VSFG lineshapes of monolayer, bilayer, and multilayer water are found to differ in characteristic ways, which is explained by their distinct density stratifications giving rise to different H-bonding patterns in the respective solvation layers.
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Affiliation(s)
- Banshi Das
- Lehrstuhl
für Theoretische Chemie, Ruhr-Universität
Bochum, 44780Bochum, Germany
| | - Sergi Ruiz-Barragan
- Lehrstuhl
für Theoretische Chemie, Ruhr-Universität
Bochum, 44780Bochum, Germany
- Departament
de Fisica, Universitat Politecnica de Catalunya, Rambla Sant Nebridi 22, 08222 Terrassa, Barcelona, Spain
| | - Dominik Marx
- Lehrstuhl
für Theoretische Chemie, Ruhr-Universität
Bochum, 44780Bochum, Germany
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4
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Deißenbeck F, Wippermann S. Dielectric Properties of Nanoconfined Water from Ab Initio Thermopotentiostat Molecular Dynamics. J Chem Theory Comput 2023; 19:1035-1043. [PMID: 36705611 PMCID: PMC9933428 DOI: 10.1021/acs.jctc.2c00959] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We discuss how to include our recently proposed thermopotentiostat technique [Deissenbeck et al. Phys. Rev. Lett. 2021, 126, 136803] into any existing ab initio molecular dynamics (AIMD) package. Using thermopotentiostat AIMD simulations in the canonical NVTΦ ensemble at a constant electrode potential, we compute the polarization bound charge and dielectric response of interfacial water from first principles.
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Affiliation(s)
- Florian Deißenbeck
- Max-Planck-Institut
für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf, Germany
| | - Stefan Wippermann
- Max-Planck-Institut
für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf, Germany,Philipps-Universität
Marburg, Renthof 5, 35032 Marburg, Germany,E-mail:
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5
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Liese S, Schlaich A, Netz RR. Dielectric Constant of Aqueous Solutions of Proteins and Organic Polymers from Molecular Dynamics Simulations. J Chem Phys 2022; 156:224902. [DOI: 10.1063/5.0089397] [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
The dielectric constant of water/oligomer mixtures, spanning the range from pure water to pure oligomeric melts, is investigated using molecular dynamics (MD) simulations. As prototypical water-soluble organic substances we consider neutral poly-glycine, poly-ethylene glycol and charged monomeric propanic acid. As the water content is reduced, the dielectric constant decreases but does not follow an ideal mixing behavior. The deviations from ideal mixing originate primarily in the non-linear relation between the oligomer mass fraction and collective polarization effects. We find that the dielectric constant is dominated by water polarization, even if the oligomer mass fraction exceeds 50%. By a double extrapolation of the MD simulation results to the limit of vanishing water fraction and to the limit of infinite oligomeric chain length, we estimate the orientational contribution to the dielectric constant of the pure polymeric melts. By this procedure, we obtain ε = 17 {plus minus} 2 for polyglycine and ε = 1 {plus minus} 0.3 for polyethylene glycol. The large difference is rationalized by polarization correlations of glycine units. Interestingly, we find constant temperature simulations to outperform replica exchange simulations in terms of equilibration speed.
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Affiliation(s)
- Susanne Liese
- University of Augsburg Institute of Physics, Germany
| | | | - Roland R. Netz
- Physics, Freie Universitat Berlin Fachbereich Physik, Germany
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6
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Abstract
It has long been anticipated that dielectric constants of polar liquids are reduced in the interfacial layer. Recent experiments and computer simulations support these expectations. A strong reduction of the dielectric constant is found in the direction perpendicular to a planar substrate, while the parallel response is bulk-like. This Perspective highlights recent theoretical calculations and simulations with an eye on relating them to properties observable in the laboratory. The average interface dielectric constant computed from simulations connects to thin films experiments, but this cannot be extended to screening of charges. In contrast to dielectric theories where a single dielectric constant gauges both the polarization energy and screening, these two signatures of dielectric polarization diverge on the molecular scale. The reduction of the dielectric constant of water in thin films is currently viewed as a combined effect of geometric confinement imposed by the substrate and the reconstruction of water hydrogen bonds in the surface layer.
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Affiliation(s)
- Dmitry V Matyushov
- School of Molecular Sciences and Department of Physics, Arizona State University, PO Box 871504, Tempe, Arizona 85287-1504, United States
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7
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Abstract
The ubiquity of aqueous solutions in contact with charged surfaces and the realization that the molecular-level details of water-surface interactions often determine interfacial functions and properties relevant in many natural processes have led to intensive research. Even so, many open questions remain regarding the molecular picture of the interfacial organization and preferential alignment of water molecules, as well as the structure of water molecules and ion distributions at different charged interfaces. While water, solutes and charge are present in each of these systems, the substrate can range from living tissues to metals. This diversity in substrates has led to different communities considering each of these types of aqueous interface. In this Review, by considering water in contact with metals, oxides and biomembranes, we show the essential similarity of these disparate systems. While in each case the classical mean-field theories can explain many macroscopic and mesoscopic observations, it soon becomes apparent that such theories fail to explain phenomena for which molecular properties are relevant, such as interfacial chemical conversion. We highlight the current knowledge and limitations in our understanding and end with a view towards future opportunities in the field.
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8
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Muñoz-Santiburcio D, Marx D. Confinement-Controlled Aqueous Chemistry within Nanometric Slit Pores. Chem Rev 2021; 121:6293-6320. [PMID: 34006106 DOI: 10.1021/acs.chemrev.0c01292] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In this Focus Review, we put the spotlight on very recent insights into the fascinating world of wet chemistry in the realm offered by nanoconfinement of water in mechanically rather rigid and chemically inert planar slit pores wherein only monolayer and bilayer water lamellae can be hosted. We review the effect of confinement on different aspects such as hydrogen bonding, ion diffusion, and charge defect migration of H+(aq) and OH-(aq) in nanoconfined water depending on slit pore width. A particular focus is put on the strongly modulated local dielectric properties as quantified in terms of anisotropic polarization fluctuations across such extremely confined water films and their putative effects on chemical reactions therein. The stunning findings disclosed only recently extend wet chemistry in particular and solvation science in general toward extreme molecular confinement conditions.
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Affiliation(s)
- Daniel Muñoz-Santiburcio
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany.,CIC nanoGUNE BRTA, Tolosa Hiribidea 76, 20018 San Sebastián, Spain
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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9
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Olivieri JF, Hynes JT, Laage D. Confined Water's Dielectric Constant Reduction Is Due to the Surrounding Low Dielectric Media and Not to Interfacial Molecular Ordering. J Phys Chem Lett 2021; 12:4319-4326. [PMID: 33914550 DOI: 10.1021/acs.jpclett.1c00447] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Liquid water confined within nanometer-sized channels exhibits a surprisingly low dielectric constant along the direction orthogonal to the channel walls. This is typically assumed to result from a pronounced heterogeneity across the sample: the dielectric constant would be bulk-like everywhere except at the interface, where it would be dramatically reduced by strong restrictions on interfacial molecules. Here we study the dielectric properties of water confined within graphene slit channels via classical molecular dynamics simulations. We show that the permittivity reduction is not due to any important alignment of interfacial water molecules, but instead to the long-ranged anisotropic dipole correlations combined with an excluded-volume effect of the low-dielectric confining material. The bulk permittivity is gradually recovered only over several nanometers due to the impact of long-range electrostatics, rather than structural features. This has important consequences for the control of, e.g., ion transport and chemical reactivity in nanoscopic channels and droplets.
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Affiliation(s)
- Jean-François Olivieri
- PASTEUR, Department of Chemistry, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - James T Hynes
- PASTEUR, Department of Chemistry, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Damien Laage
- PASTEUR, Department of Chemistry, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
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10
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Rezaei M, Mitterwallner BG, Loche P, Uematsu Y, Netz RR, Bonthuis DJ. Interfacial, Electroviscous, and Nonlinear Dielectric Effects on Electrokinetics at Highly Charged Surfaces. J Phys Chem B 2021; 125:4767-4778. [PMID: 33939436 PMCID: PMC8154604 DOI: 10.1021/acs.jpcb.0c11280] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The dielectric constant
and the viscosity of water at the interface
of hydrophilic surfaces differ from their bulk values, and it has
been proposed that the deviation is caused by the strong electric
field and the high ion concentration in the interfacial layer. We
calculate the dependence of the dielectric constant and the viscosity
of bulk electrolytes on the electric field and the salt concentration.
Incorporating the concentration and field-dependent dielectric constant
and viscosity in the extended Poisson–Boltzmann and Stokes
equations, we calculate the electro-osmotic mobility. We compare the
results to literature experimental data and explicit molecular dynamics
simulations of OH-terminated surfaces and show that it is necessary
to additionally include the presence of a subnanometer wide interfacial
water layer, the properties of which are drastically transformed by
the sheer presence of the interface. We conclude that the origin of
the anomalous behavior of aqueous interfacial layers cannot be found
in electrostriction or electroviscous effects caused by the interfacial
electric field and ion concentration. Instead, it is primarily caused
by the intrinsic ordering and orientation of the interfacial water
layer.
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Affiliation(s)
- Majid Rezaei
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | | | - Philip Loche
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Yuki Uematsu
- Department of Physics, Kyushu University, 819-0395 Fukuoka, Japan
| | - Roland R Netz
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Douwe Jan Bonthuis
- Institute of Theoretical and Computational Physics, Graz University of Technology, 8010 Graz, Austria
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11
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Deißenbeck F, Freysoldt C, Todorova M, Neugebauer J, Wippermann S. Dielectric Properties of Nanoconfined Water: A Canonical Thermopotentiostat Approach. PHYSICAL REVIEW LETTERS 2021; 126:136803. [PMID: 33861101 DOI: 10.1103/physrevlett.126.136803] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 08/14/2020] [Accepted: 02/26/2021] [Indexed: 06/12/2023]
Abstract
We introduce a novel approach to sample the canonical ensemble at constant temperature and applied electric potential. Our approach can be straightforwardly implemented into any density-functional theory code. Using thermopotentiostat molecular dynamics simulations allows us to compute the dielectric constant of nanoconfined water without any assumptions for the dielectric volume. Compared to the commonly used approach of calculating dielectric properties from polarization fluctuations, our thermopotentiostat technique reduces the required computational time by 2 orders of magnitude.
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Affiliation(s)
- F Deißenbeck
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237Düsseldorf, Germany
| | - C Freysoldt
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237Düsseldorf, Germany
| | - M Todorova
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237Düsseldorf, Germany
| | - J Neugebauer
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237Düsseldorf, Germany
| | - S Wippermann
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237Düsseldorf, Germany
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12
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Motevaselian MH, Aluru NR. Universal Reduction in Dielectric Response of Confined Fluids. ACS NANO 2020; 14:12761-12770. [PMID: 32966055 DOI: 10.1021/acsnano.0c03173] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Dielectric permittivity is central to many biological and physiochemical systems, as it affects the long-range electrostatic interactions. Similar to many fluid properties, confinement greatly alters the dielectric response of polar liquids. Many studies have focused on the reduction of the dielectric response of water under confinement. Here, using molecular dynamics simulations, statistical-mechanical theories, and multiscale methods, we study the out-of-plane (z-axis) dielectric response of protic and aprotic fluids confined inside slit-like graphene channels. We show that the reduction in perpendicular permittivity is universal for all the fluids and exhibits a Langevin-like behavior as a function of channel width. We show that this reduction is due to the favorable in-plane (x-y plane) dipole-dipole electrostatic interactions of the interfacial fluid layer. Furthermore, we observe an anomalously low dielectric response under an extreme confinement.
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Affiliation(s)
- Mohammad H Motevaselian
- Department of Mechanical Science and Engineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Narayana R Aluru
- Department of Mechanical Science and Engineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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13
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Liang D, Dahal U, Zhang YK, Lochbaum C, Ray D, Hamers RJ, Pedersen JA, Cui Q. Interfacial water and ion distribution determine ζ potential and binding affinity of nanoparticles to biomolecules. NANOSCALE 2020; 12:18106-18123. [PMID: 32852025 DOI: 10.1039/d0nr03792c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The molecular features that dictate interactions between functionalized nanoparticles and biomolecules are not well understood. This is in part because for highly charged nanoparticles in solution, establishing a clear connection between the molecular features of surface ligands and common experimental observables such as ζ potential requires going beyond the classical models based on continuum and mean field models. Motivated by these considerations, molecular dynamics simulations are used to probe the electrostatic properties of functionalized gold nanoparticles and their interaction with a charged peptide in salt solutions. Counterions are observed to screen the bare ligand charge to a significant degree even at the moderate salt concentration of 50 mM. As a result, the apparent charge density and ζ potential are largely insensitive to the bare ligand charge densities, which fall in the range of ligand densities typically measured experimentally for gold nanoparticles. While this screening effect was predicted by classical models such as the Manning condensation theory, the magnitudes of the apparent surface charge from microscopic simulations and mean-field models are significantly different. Moreover, our simulations found that the chemical features of the surface ligand (e.g., primary vs. quaternary amines, heterogeneous ligand lengths) modulate the interfacial ion and water distributions and therefore the interfacial potential. The importance of interfacial water is further highlighted by the observation that introducing a fraction of hydrophobic ligands enhances the strength of electrostatic binding of the charged peptide. Finally, the simulations highlight that the electric double layer is perturbed upon binding interactions. As a result, it is the bare charge density rather than the apparent charge density or ζ potential that better correlates with binding affinity of the nanoparticle to a charged peptide. Overall, our study highlights the importance of molecular features of the nanoparticle/water interface and underscores a set of design rules for the modulation of electrostatic driven interactions at nano/bio interfaces.
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Affiliation(s)
- Dongyue Liang
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
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14
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Loche P, Ayaz C, Wolde-Kidan A, Schlaich A, Netz RR. Universal and Nonuniversal Aspects of Electrostatics in Aqueous Nanoconfinement. J Phys Chem B 2020; 124:4365-4371. [PMID: 32364728 DOI: 10.1021/acs.jpcb.0c01967] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dielectric water properties, which significantly change in confinement, determine electrostatic interactions and thereby influence all molecular forces and chemical reactions. We present comparative simulations of water between graphene sheets, decanol monolayers, and phospholipid and glycolipid bilayers. Generally, dielectric profiles strongly differ in perpendicular and parallel surface directions and for large surface separation decay to the bulk value 1-2 nm away from the surface. Polar surface groups enhance the local interfacial dielectric response and for phospholipid bilayers induce a giant parallel contribution. A mapping on a box model with asymptotically determined effective water layer widths demonstrates that the perpendicular effective dielectric constant for all systems decreases for confinement below a nanometer, while the parallel one stays rather constant. The confinement-dependent perpendicular effective dielectric constant for graphene is in agreement with experimental data only if the effective water layer width is suitably adjusted. The interactions between two charges at small separation depend on the product of parallel and perpendicular effective water dielectric components; for large separation the interactions depend on the confining medium. For metallic confining media the interactions at large separation decay exponentially with a decay length that depends on the ratio of the effective parallel and perpendicular water dielectric components.
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Affiliation(s)
- Philip Loche
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Cihan Ayaz
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | | | | | - Roland R Netz
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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15
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Ruiz-Barragan S, Muñoz-Santiburcio D, Körning S, Marx D. Quantifying anisotropic dielectric response properties of nanoconfined water within graphene slit pores. Phys Chem Chem Phys 2020; 22:10833-10837. [DOI: 10.1039/d0cp00916d] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Water presents puzzling properties once it gets confined, in particular its dielectric response becomes highly anisotropic. Here, we analyze the dielectric response of water within graphene slit pores based on molecular dynamics simulations.
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Affiliation(s)
- Sergi Ruiz-Barragan
- Lehrstuhl für Theoretische Chemie Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| | - Daniel Muñoz-Santiburcio
- Lehrstuhl für Theoretische Chemie Ruhr-Universität Bochum
- 44780 Bochum
- Germany
- CIC nanoGUNE BRTA
- Tolosa Hiribidea 76
| | - Saskia Körning
- Lehrstuhl für Theoretische Chemie Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie Ruhr-Universität Bochum
- 44780 Bochum
- Germany
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16
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Loche P, Ayaz C, Schlaich A, Uematsu Y, Netz RR. Giant Axial Dielectric Response in Water-Filled Nanotubes and Effective Electrostatic Ion-Ion Interactions from a Tensorial Dielectric Model. J Phys Chem B 2019; 123:10850-10857. [PMID: 31765168 DOI: 10.1021/acs.jpcb.9b09269] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Molecular dynamics simulations in conjunction with effective medium theory are used to investigate dielectric effects in water-filled nanotubes. The resulting effective axial dielectric constant shows a divergent increase for small nanotube radii that depends on the nanotube length, while the effective radial dielectric constant decreases significantly for thin nanotubes. By solving Poisson's equation for an anisotropic dielectric medium in cylindrical geometry, we show that the axial ion-ion interaction depends for small separations primarily on the radial dielectric constant, not on the axial one. This means that electrostatic ion-ion interactions in thin water-filled nanotubes are on the linear dielectric level significantly enhanced due to water confinement effects at small separations, while at large separations the outside medium dominates. If the outside medium is metallic, then the ion-ion interaction decays exponentially for large ion separation.
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Affiliation(s)
- Philip Loche
- Fachbereich Physik , Freie Universität Berlin , 14195 Berlin , Germany
| | - Cihan Ayaz
- Fachbereich Physik , Freie Universität Berlin , 14195 Berlin , Germany
| | | | - Yuki Uematsu
- Laboratoire de Physique de l'Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université , Université de Paris , F-75005 Paris , France.,Department of Physics , Kyushu University , 819-0395 Fukuoka , Japan
| | - Roland R Netz
- Fachbereich Physik , Freie Universität Berlin , 14195 Berlin , Germany
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17
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Ohnuki J, Sato T, Sasaki T, Umezawa K, Takano M. Ohnuki et al. Reply. PHYSICAL REVIEW LETTERS 2019; 123:049602. [PMID: 31491245 DOI: 10.1103/physrevlett.123.049602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Indexed: 06/10/2023]
Affiliation(s)
- Jun Ohnuki
- Department of Pure and Applied Physics, Waseda University, Tokyo 169-8555, Japan
| | - Takato Sato
- Department of Pure and Applied Physics, Waseda University, Tokyo 169-8555, Japan
| | - Tohru Sasaki
- Department of Pure and Applied Physics, Waseda University, Tokyo 169-8555, Japan
| | - Koji Umezawa
- Department of Biomedical Engineering/Institute for Biomedical Sciences, Shinshu University, Nagano, 399-4598, Japan
| | - Mitsunori Takano
- Department of Pure and Applied Physics, Waseda University, Tokyo 169-8555, Japan
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