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Li Y, Huang Y, Lu X, Wang M. Criteria of Distribution Transitions in Dispersed Multiphase Systems Based on an Extended Lattice Model. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:17021-17030. [PMID: 37993781 DOI: 10.1021/acs.langmuir.3c01579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2023]
Abstract
Dispersed multiphase systems are ubiquitous in biological systems, energy industries, and medical science. The distribution transition of the dispersed phase is critical to the properties and functions of the multiphase systems, among which the agglomeration, adsorption, and extraction processes are of most significance due to their impact on the colloidal stability, interface modification, and particle synthesis. To reveal fundamental correlations between the macroscopic particle distributions and the microscopic interactions, general thermodynamic models of the dispersed multiphase systems are needed. Here, based on Meyer's model, which is restricted to binary isotropic mixtures, we propose a novel extended lattice model that can be applied to multicomponent anisotropic mixtures with interfaces considered. For agglomeration, adsorption, and extraction processes, the approximate free energy differences between the initial distribution and the final distribution are obtained. Based on the minimum free energy principle, the above free energy differences are used to derive three criteria for the prediction of the preferable distribution of the system with given interparticle interaction potentials. While the quasi-uniform number density assumption is still required for all the previous lattice models, the long-range interactions neglected by previous lattice models are incorporated. The validity of our model and criteria is verified by many-body dissipative particle dynamics (mDPD) simulations. By tuning the interaction coefficients between mDPD particles, the simulated distribution transitions for all the agglomeration, adsorption, and extraction cases perfectly match the predictions from the three criteria. The good agreement between the theoretical predictions and the mDPD simulation results shows the great potential of our model for applications in various dispersed multiphase systems.
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Affiliation(s)
- Yiran Li
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Yunfan Huang
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Xukang Lu
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Moran Wang
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
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2
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Telles IM, Arfan M, Dos Santos AP. Effects of electrostatic coupling and surface polarization on polyelectrolyte brush structure. J Chem Phys 2023; 158:144902. [PMID: 37061472 DOI: 10.1063/5.0147056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023] Open
Abstract
In this work, we perform molecular dynamics simulations to study a spherical polyelectrolyte brush. We explore the effects of surface polarization and electrostatic coupling on brush size and distribution of counterions. The method of image charges is considered to take into account surface polarization, considering a metallic, an unpolarizable, and a dielectric nano-core. It is observed that, for all cases, a moderate shrinking-swelling effect appears with an increase in the electrostatic coupling parameter. This effect occurs under high Manning ratios. The curves relating the average size of polyelectrolyte brush as a function of coupling show a minimum. The results show that the grafting density of polyelectrolytes on the nano-core surface plays an important role in the polarization effect. We consider a modified Poisson-Boltzmann theory to describe the counterion profiles around the brush in the case of unpolarizable nano-cores and weak electrostatic coupling.
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Affiliation(s)
- Igor M Telles
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Muhammad Arfan
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Alexandre P Dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
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3
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Palaia I, Goyal A, Del Gado E, Šamaj L, Trizac E. Like-Charge Attraction at the Nanoscale: Ground-State Correlations and Water Destructuring. J Phys Chem B 2022; 126:3143-3149. [PMID: 35420420 DOI: 10.1021/acs.jpcb.2c00028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Like-charge attraction, driven by ionic correlations, challenges our understanding of electrostatics both in soft and hard matter. For two charged planar surfaces confining counterions and water, we prove that, even at relatively low correlation strength, the relevant physics is the ground-state one, oblivious of fluctuations. Based on this, we derive a simple and accurate interaction pressure that fulfills known exact requirements and can be used as an effective potential. We test this equation against implicit-solvent Monte Carlo simulations and against explicit-solvent simulations of cement and several types of clays. We argue that water destructuring under nanometric confinement drastically reduces dielectric screening, enhancing ionic correlations. Our equation of state at reduced permittivity therefore explains the exotic attractive regime reported for these materials, even in the absence of multivalent counterions.
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Affiliation(s)
- Ivan Palaia
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Abhay Goyal
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets, N.W., Washington, D.C. 20057, United States
| | - Emanuela Del Gado
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets, N.W., Washington, D.C. 20057, United States
| | - Ladislav Šamaj
- Institute of Physics, Slovak Academy of Sciences, 84511 Bratislava, Slovakia
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4
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Bakhshandeh A, Frydel D, Levin Y. Reactive Monte Carlo simulations for charge regulation of colloidal particles. J Chem Phys 2022; 156:014108. [PMID: 34998334 DOI: 10.1063/5.0077956] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We use a reactive Monte Carlo simulation method and the primitive model of electrolyte to study acid-base equilibrium that controls charge regulation in colloidal systems. The simulations are performed in a semi-grand canonical ensemble in which colloidal suspension is in contact with a reservoir of salt and strong acid. The interior of colloidal particles is modeled as a low dielectric medium, different from the surrounding water. The effective colloidal charge is calculated for different numbers of surface acidic groups, pH, salt concentrations, and types of electrolyte. In the case of potassium chloride, the titration curves are compared with the experimental measurements obtained using potentiometric titration. A good agreement is found between simulations and experiments. In the case of lithium chloride, the specific ionic adsorption is taken into account through the partial dehydration of lithium ion.
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Affiliation(s)
- Amin Bakhshandeh
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Derek Frydel
- Department of Chemistry, Universidad Técnica Federico Santa María, Campus San Joaquin, 7820275 Santiago, Chile
| | - Yan Levin
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
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5
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Bakhshandeh A, Segala M, Escobar Colla T. Equilibrium Conformations and Surface Charge Regulation of Spherical Polymer Brushes in Stretched Regimes. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c02077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Amin Bakhshandeh
- Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Rio Grande do Sul, Brazil
- Departamento de Físico-Química, Instituto de Química, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Rio Grande do Sul, Brazil
| | - Maximiliano Segala
- Instituto de Física, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, Minas Gerais, Brazil
- Departamento de Físico-Química, Instituto de Química, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Rio Grande do Sul, Brazil
| | - Thiago Escobar Colla
- Instituto de Física, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, Minas Gerais, Brazil
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6
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Bakhshandeh A, Segala M, Colla T. Electrolytes in regimes of strong confinement: surface charge modulations, osmotic equilibrium and electroneutrality. SOFT MATTER 2020; 16:10488-10505. [PMID: 33073284 DOI: 10.1039/d0sm01386b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In the present work, we study an electrolyte solution confined between planar surfaces with nanopatterned charged domains, which has been connected to a bulk ionic reservoir. The system is investigated through an improved Monte Carlo (MC) simulation method, suitable for simulation of electrolytes in the presence of modulated surface charge distributions. We also employ a linear approach in the spirit of the classical Debye-Hückel approximation, which allows one to obtain explicit expressions for the averaged potentials, ionic profiles, effective surface interactions and the net ionic charge confined between the walls. Emphasis is placed on the limit of strongly confined electrolytes, in which case local electroneutrality in the inter-surface space might not be fulfilled. In order to access the effects of such a lack of local charge neutrality on the ion-induced interactions between surfaces with modulated charge domains, we consider two distinct model systems for the confined electrolyte: one in which a salt reservoir is explicitly taken into account via the osmotic equilibrium with an electrolyte of fixed bulk concentration, and a second one in which the equilibrium with a charge neutral ionic reservoir is implicitly considered. While in the former case the osmotic ion exchange might lead to non-vanishing net charges, in the latter model charge neutrality is enforced through the appearance of an implicit Donnan potential across the charged interfaces. A strong dependence of the ion-induced surface interactions on the employed model system is observed at all surface separations. These findings strongly suggest that due care is to be taken while choosing among different scenarios to describe the ion exchange in electrolytes confined between charged surfaces, even in cases when the monopole (non zero net charge) surface contributions are absent.
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Affiliation(s)
- Amin Bakhshandeh
- Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, RS, Brazil. and Departamento de Físico-Química, Instituto de Química, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, RS, Brazil.
| | - Maximiliano Segala
- Departamento de Físico-Química, Instituto de Química, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, RS, Brazil.
| | - Thiago Colla
- Instituto de Física, Universidade Federal de Ouro Preto, 35400-000, Ouro Preto, MG, Brazil.
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7
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Bakhshandeh A, dos Santos AP, Levin Y. Interaction between Charge-Regulated Metal Nanoparticles in an Electrolyte Solution. J Phys Chem B 2020; 124:11762-11770. [DOI: 10.1021/acs.jpcb.0c09446] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Amin Bakhshandeh
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
| | - Alexandre P. dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
| | - Yan Levin
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
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8
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Lau AWC, Sokoloff JB. Enhancement of the ion concentration in a salt solution near a wall due to electrical image potentials and enhancement of surface tension due to the presence of salt. Phys Rev E 2020; 102:052606. [PMID: 33327151 DOI: 10.1103/physreve.102.052606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 10/23/2020] [Indexed: 06/12/2023]
Abstract
Effects of electrical image potentials on the salt ion concentration near a solid wall are studied using a one-loop approximation treatment of the grand canonical partition function, which is the Debye-Hückel approximation. Electrical image potentials resulting from both metallic and dielectric walls of dielectric constant larger than that of water near the wall are considered. Our treatment of this problem supports the conclusions of an earlier publication by one of the authors which shows that near a solid wall there should be a high concentration of ions, resulting from image potentials. We have also applied our treatment to the increase of the surface tension of a liquid that occurs when salt is dissolved in the liquid. Our treatment gives the -c_{s}log(c_{s}) dependence of the surface tension found by Onsager and Samarasa in the small c_{s} limit, where c_{s} is the salt concentration.
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Affiliation(s)
- A W C Lau
- Physics Department, Florida Atlantic University, Boca Raton, Florida 33431, USA
| | - J B Sokoloff
- Physics Department, Florida Atlantic University, Boca Raton, Florida 33431, USA
- Physics Department, Northeastern University, Boston, Massachusetts 02115, USA
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9
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Šamaj L, Trulsson M, Trizac E. Strong-coupling theory of counterions with hard cores between symmetrically charged walls. Phys Rev E 2020; 102:042604. [PMID: 33212638 DOI: 10.1103/physreve.102.042604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/16/2020] [Indexed: 06/11/2023]
Abstract
By a combination of Monte Carlo simulations and analytical calculations, we investigate the effective interactions between highly charged planar interfaces, neutralized by mobile counterions (salt-free system). While most previous analysis have focused on pointlike counterions, we treat them as charged hard spheres. We thus work out the fate of like-charge attraction when steric effects are at work. The analytical approach partitions counterions in two subpopulations, one for each plate, and integrates out one subpopulation to derive an effective Hamiltonian for the remaining one. The effective Hamiltonian features plaquette four-particle interactions, and it is worked out by computing a Gibbs-Bogoliubov inequality for the free energy. At the root of the treatment is the fact that under strong electrostatic coupling, the system of charges forms an ordered arrangement, that can be affected by steric interactions. Fluctuations around the reference positions are accounted for. To dominant order at high coupling, it is found that steric effects do not significantly affect the interplate effective pressure, apart at small distances where hard-sphere overlap are unavoidable, and thus rule out configurations.
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Affiliation(s)
- Ladislav Šamaj
- Institute of Physics, Slovak Academy of Sciences, 84511 Bratislava, Slovakia
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10
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Sokoloff JB. Effects of electrical image forces on salt dissolved in water. Phys Rev E 2020; 101:013110. [PMID: 32069554 DOI: 10.1103/physreve.101.013110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Indexed: 11/07/2022]
Abstract
It will be shown that for a solution of salt dissolved in water in contact with a metallic or dielectric wall, the concentration of salt ions (both positive and negative) near the wall can be large enough to exceed the salt's solubility limit, as a result of electrical image charge forces. In addition, since the dielectric constant of water increases from 2.1 at the wall to 81 at about 1 nm from a solid wall, there will be an attractive image potential near the plane on which this increase of the dielectric constant occurs. Such large ion concentrations could possibly be used in water desalination.
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Affiliation(s)
- J B Sokoloff
- Physics Department and Center for Interdisciplinary Research in Complex Systems, Northeastern University, Boston, Massachusetts 02115, USA
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11
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Bakhshandeh A, Segala M. Adsorption of polyelectrolytes on charged microscopically patterned surfaces. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111673] [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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12
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Qin J. Charge polarization near dielectric interfaces and the multiple-scattering formalism. SOFT MATTER 2019; 15:2125-2134. [PMID: 30762054 DOI: 10.1039/c8sm02196a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Interfacial charge polarization is ubiquitous in systems with sharp dielectric contrast. Fully resolving the interfacial charges often relies on demanding numerical algorithms to solve the boundary value problem. The recent development of an analytical multiple-scattering formalism to solve the interfacial charge polarization problem for particles carrying monopolar, dipolar, and multipolar charges is reviewed. Every term produced in this formalism has a simple interpretation, and terms for spherical particles can be rapidly evaluated using an image-line construction. Several practical applications of this formalism are illustrated. A dielectric virial expansion for polarizable particles based on this formalism is also described. The origins of singular polarization charges for particles in close contact are explained and evaluated for both dielectric and conducting spheres.
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Affiliation(s)
- Jian Qin
- Department of Chemical Engineering, Stanford University, Stanford 94305, USA.
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13
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Fraenkel D. An improved theory of the electric conductance of ionic solutions based on the concept of the ion-atmosphere's smaller-ion shell. Phys Chem Chem Phys 2018; 20:29896-29909. [PMID: 30474091 DOI: 10.1039/c8cp06000b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although the electric conductivity of ionic solutions is of great importance in science and technology, complete understanding of the physical factors and principles underlying ion and charge transport in solution has so far been missing. The Debye-Hückel-Onsager (DHO) theory of the equivalent ionic conductivity (λi for single ion i, Λ for a binary electrolyte) is a limiting law of only a few electrolyte valence families, and its extension to solution of finite concentration has not been entirely successful; at most, it has led to semiempirical expressions of λi or Λ vs. concentration (c), incorporating adjustable parameters of no clear physical meaning. Improving the description of the ion atmosphere and including in the conductivity model the smaller-ion shell (SiS) of this atmosphere (D. Fraenkel, Mol. Phys., 2010, 108, 1435) allow now an extension of the DHO theory to a "DHO-SiS" theory that offers analytic expressions for λi and Λ as a function of c without adjustable parameters. The fit with experiment is very good, often excellent, for many electrolytes of the various valence families. λi values can be converted to single-ion activity coefficients, γis, suggesting that the latter ionic factors do have physical validity, contrary to what many literature sources claim. Together with the recently proposed theory of the limiting conductivities, λ0i and Λ0 (D. Fraenkel, Mol. Phys., 2018, 116, 2271), the new theory offers a simple and comprehensive ion conductivity treatment that improves upon existing theoretical treatments, with λi and Λ expressed by ionic sizes instead of λ0i and Λ0.
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Affiliation(s)
- Dan Fraenkel
- Eltron Research & Development LLC, 4600 Nautilus Court South, Boulder, Colorado 80301-3241, USA.
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14
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15
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Dos Santos AP, Girotto M, Levin Y. Simulations of Coulomb systems confined by polarizable surfaces using periodic Green functions. J Chem Phys 2018; 147:184105. [PMID: 29141417 DOI: 10.1063/1.4997420] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present an efficient approach for simulating Coulomb systems confined by planar polarizable surfaces. The method is based on the solution of the Poisson equation using periodic Green functions. It is shown that the electrostatic energy arising from the surface polarization can be decoupled from the energy due to the direct Coulomb interaction between the ions. This allows us to combine an efficient Ewald summation method, or any other fast method for summing over the replicas, with the polarization contribution calculated using Green function techniques. We apply the method to calculate density profiles of ions confined between the charged dielectric and metal surfaces.
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Affiliation(s)
- Alexandre P Dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Matheus Girotto
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Yan Levin
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
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16
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Colla T, Nunes Lopes L, Dos Santos AP. Ionic size effects on the Poisson-Boltzmann theory. J Chem Phys 2018; 147:014104. [PMID: 28688437 DOI: 10.1063/1.4990737] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this paper, we develop a simple theory to study the effects of ionic size on ionic distributions around a charged spherical particle. We include a correction to the regular Poisson-Boltzmann equation in order to take into account the size of ions in a mean-field regime. The results are compared with Monte Carlo simulations and a density functional theory based on the fundamental measure approach and a second-order bulk expansion which accounts for electrostatic correlations. The agreement is very good even for multivalent ions. Our results show that the theory can be applied with very good accuracy in the description of ions with highly effective ionic radii and low concentration, interacting with a colloid or a nanoparticle in an electrolyte solution.
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Affiliation(s)
- Thiago Colla
- Instituto de Física, Universidade Federal de Ouro Preto, CEP 35400-000 Ouro Preto, MG, Brazil
| | - Lucas Nunes Lopes
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Alexandre P Dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
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17
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Petersen B, Roa R, Dzubiella J, Kanduč M. Ionic structure around polarizable metal nanoparticles in aqueous electrolytes. SOFT MATTER 2018; 14:4053-4063. [PMID: 29670972 PMCID: PMC5968446 DOI: 10.1039/c8sm00399h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/04/2018] [Indexed: 06/08/2023]
Abstract
Metal nanoparticles are receiving increased scientific attention owing to their unique physical and chemical properties that make them suitable for a wide range of applications in diverse fields, such as electrochemistry, biochemistry, and nanomedicine. Their high metallic polarizability is a crucial determinant that defines their electrostatic character in various electrolyte solutions. Here, we introduce a continuum-based model of a metal nanoparticle with explicit polarizability in the presence of different kinds of electrolytes. We employ several, variously sophisticated, theoretical approaches, corroborated by Monte Carlo simulations in order to elucidate the basic electrostatics principles of the model. We investigate how different kinds of asymmetries between the ions result in non-trivial phenomena, such as charge separation and a build-up of a so-called zero surface-charge double layer.
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Affiliation(s)
- Bendix Petersen
- Research Group for Simulations of Energy Materials , Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner-Platz 1 , D-14109 Berlin , Germany . ;
- Institut für Physik , Humboldt-Universität zu Berlin , Newtonstr. 15 , D-12489 Berlin , Germany
| | - Rafael Roa
- Research Group for Simulations of Energy Materials , Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner-Platz 1 , D-14109 Berlin , Germany . ;
- Departamento de Física Aplicada I , Facultad de Ciencias , Universidad de Málaga , Campus de Teatinos s/n , E-29071 Málaga , Spain
| | - Joachim Dzubiella
- Research Group for Simulations of Energy Materials , Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner-Platz 1 , D-14109 Berlin , Germany . ;
- Physikalisches Institut , Albert-Ludwigs-Universität Freiburg , Hermann-Herder Str. 3 , D-79104 Freiburg , Germany
| | - Matej Kanduč
- Research Group for Simulations of Energy Materials , Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner-Platz 1 , D-14109 Berlin , Germany . ;
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18
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Palaia I, Trulsson M, Šamaj L, Trizac E. A correlation-hole approach to the electric double layer with counter-ions only. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1471234] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- Ivan Palaia
- LPTMS, CNRS, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | | | - Ladislav Šamaj
- Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Emmanuel Trizac
- LPTMS, CNRS, Université Paris-Sud, Université Paris-Saclay, Orsay, France
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19
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Ether DS, Rosa FSS, Tibaduiza DM, Pires LB, Decca RS, Neto PAM. Double-layer force suppression between charged microspheres. Phys Rev E 2018; 97:022611. [PMID: 29548099 DOI: 10.1103/physreve.97.022611] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Indexed: 11/07/2022]
Abstract
In this paper we propose a protocol to suppress double-layer forces between two microspheres immersed in a dielectric medium, being one microsphere metallic at a controlled potential ψ_{M} and the other a charged one either metallic or dielectric. The approach is valid for a wide range of distances between them. We show that, for a given distance between the two microspheres, the double-layer force can be totally suppressed by simply tuning ψ_{M} up to values dictated by the linearized Poisson-Boltzmann equation. Our key finding is that such values can be substantially different from the ones predicted by the commonly used proximity force approximation, also known as the Derjaguin approximation, even in situations where the latter is expected to be accurate. The proposed procedure can be used to suppress the double-layer interaction in force spectroscopy experiments, thus paving the way for measurements of other surface interactions, such as Casimir dispersion forces.
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Affiliation(s)
- D S Ether
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil.,Laboratório de Pinças Óticas - LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - F S S Rosa
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil
| | - D M Tibaduiza
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil
| | - L B Pires
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil.,Laboratório de Pinças Óticas - LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - R S Decca
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, USA
| | - P A Maia Neto
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil.,Laboratório de Pinças Óticas - LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
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20
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Wang ZY, Zhang P, Ma Z. On the physics of both surface overcharging and charge reversal at heterophase interfaces. Phys Chem Chem Phys 2018; 20:4118-4128. [DOI: 10.1039/c7cp08117k] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A series of Monte Carlo simulations are employed to reveal the physics of both surface overcharging and charge reversal at a negatively charged dielectric interface exposed to a bulk solution containing a +2:−1 electrolyte in the absence and presence of a monovalent salt.
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Affiliation(s)
- Zhi-Yong Wang
- School of Science
- Chongqing University of Technology
- Chongqing 400054
- China
| | - Pengli Zhang
- School of Science
- Chongqing University of Technology
- Chongqing 400054
- China
| | - Zengwei Ma
- School of Science
- Chongqing University of Technology
- Chongqing 400054
- China
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21
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Tergolina VB, dos Santos AP. Effect of dielectric discontinuity on a spherical polyelectrolyte brush. J Chem Phys 2017; 147:114103. [DOI: 10.1063/1.5002526] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Vinicius B. Tergolina
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Alexandre P. dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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22
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Wang ZY, Wu J. Ion association at discretely-charged dielectric interfaces: Giant charge inversion. J Chem Phys 2017; 147:024703. [DOI: 10.1063/1.4986792] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [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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Liu L, Nakamura I. Solvation Energy of Ions in Polymers: Effects of Chain Length and Connectivity on Saturated Dipoles near Ions. J Phys Chem B 2017; 121:3142-3150. [DOI: 10.1021/acs.jpcb.7b00671] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lijun Liu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Issei Nakamura
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, United States
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24
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Šamaj L, Dos Santos AP, Levin Y, Trizac E. Mean-field beyond mean-field: the single particle view for moderately to strongly coupled charged fluids. SOFT MATTER 2016; 12:8768-8773. [PMID: 27714365 DOI: 10.1039/c6sm01360k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In a counter-ion only charged fluid, Coulomb coupling is quantified by a single dimensionless parameter. Yet, the theoretical treatment of moderately to strongly coupled charged fluids is a difficult task, central to the understanding of a wealth of soft matter problems, including biological systems. We show that the corresponding coupling regime can be remarkably well described by a single particle treatment, which, at variance with previous works, takes due account of inter-ionic interactions. To this end, the prototypical problem of a planar charged dielectric interface is worked out. Testing our predictions against Monte Carlo simulation data reveals an excellent agreement.
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Affiliation(s)
- Ladislav Šamaj
- Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Alexandre P Dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, CP 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Yan Levin
- Instituto de Física, Universidade Federal do Rio Grande do Sul, CP 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Emmanuel Trizac
- LPTMS, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
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25
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dos Santos AP, Girotto M, Levin Y. Simulations of Polyelectrolyte Adsorption to a Dielectric Like-Charged Surface. J Phys Chem B 2016; 120:10387-10393. [DOI: 10.1021/acs.jpcb.6b06002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Alexandre P. dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Matheus Girotto
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Yan Levin
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
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26
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Wang ZY, Ma Z. Examining the Contributions of Image-Charge Forces to Charge Reversal: Discrete Versus Continuum Modeling of Surface Charges. J Chem Theory Comput 2016; 12:2880-8. [DOI: 10.1021/acs.jctc.6b00057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhi-Yong Wang
- School
of Optoelectronic Information, Chongqing University of Technology, Chongqing 400054, China
| | - Zengwei Ma
- School
of Optoelectronic Information, Chongqing University of Technology, Chongqing 400054, China
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27
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Abstract
Screening is one of the most important concepts in the study of charged systems. Near a dielectric interface, the ion distribution in a salt solution can be highly nonuniform. Here, we develop a theory that self-consistently treats the inhomogeneous screening effects. At higher concentrations when the bulk Debye screening length is comparable to the Bjerrum length, the double layer structure and interfacial properties are significantly affected by the inhomogeneous screening. In particular, the depletion zone is considerably wider than that predicted by the bulk screening approximation or the WKB approximation. The characteristic length of the depletion layer in this regime scales with the Bjerrum length, resulting in a linear increase of the negative adsorption of ions with concentration, in agreement with experiments. For asymmetric salts, inhomogeneous screening leads to enhanced charge separation and surface potential.
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Affiliation(s)
- Rui Wang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Zhen-Gang Wang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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28
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Abstract
Despite the ubiquitous character and relevance of the electric double layer in the entire realm of interface and colloid science, very little is known of the effect that surface heterogeneity exerts on the underlying mechanisms of ion adsorption. Herein, computer simulations offer a perspective that, in sharp contrast to the homogeneously charged surface, discrete groups promote multivalent counterion binding, leading to charge reversal but possibly having not a sign change of the electrophoretic mobility. Counterintuitively, the introduction of dielectric images yields a significantly greater accumulation of counterions, which further facilitates the magnitude of charge reversal. The reported results are very sensitive to both the degree of ion hydration and the representation of surface charges. Our findings shed light on the mechanism for charge reversal over a broad range of coupling regimes operating the adsorption of counterions through surface group bridging attraction with their own images and provide opportunities for experimental studies and theoretical development.
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Affiliation(s)
- Zhi-Yong Wang
- School of Optoelectronic Information, Chongqing University of Technology, Chongqing 400054, People's Republic of China
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29
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Girotto M, dos Santos AP, Levin Y. Interaction of Charged Colloidal Particles at the Air–Water Interface. J Phys Chem B 2015; 120:5817-22. [DOI: 10.1021/acs.jpcb.5b10105] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matheus Girotto
- Instituto
de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051,
CEP 91501-970, Porto Alegre, RS, Brazil
| | - Alexandre P. dos Santos
- Instituto
de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051,
CEP 91501-970, Porto Alegre, RS, Brazil
| | - Yan Levin
- Instituto
de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051,
CEP 91501-970, Porto Alegre, RS, Brazil
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30
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Jing Y, Jadhao V, Zwanikken JW, Olvera de la Cruz M. Ionic structure in liquids confined by dielectric interfaces. J Chem Phys 2015; 143:194508. [DOI: 10.1063/1.4935704] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- Yufei Jing
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Vikram Jadhao
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Jos W. Zwanikken
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Monica Olvera de la Cruz
- Departments of Materials Science and Engineering, Chemistry, Chemical and Biological Engineering, and Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA
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31
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dos Santos AP, Levin Y. Electrolytes between dielectric charged surfaces: Simulations and theory. J Chem Phys 2015; 142:194104. [PMID: 26001444 DOI: 10.1063/1.4921221] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We present a simulation method to study electrolyte solutions in a dielectric slab geometry using a modified 3D Ewald summation. The method is fast and easy to implement, allowing us to rapidly resum an infinite series of image charges. In the weak coupling limit, we also develop a mean-field theory which allows us to predict the ionic distribution between the dielectric charged plates. The agreement between both approaches, theoretical and simulational, is very good, validating both methods. Examples of ionic density profiles in the strong electrostatic coupling limit are also presented. Finally, we explore the confinement of charge asymmetric electrolytes between neutral surfaces.
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Affiliation(s)
- Alexandre P dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
| | - Yan Levin
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
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32
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Lue L, Linse P. Ions confined in spherical dielectric cavities modeled by a splitting field-theory. J Chem Phys 2015; 142:144902. [DOI: 10.1063/1.4917256] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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33
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Wang R, Wang ZG. On the theoretical description of weakly charged surfaces. J Chem Phys 2015; 142:104705. [PMID: 25770555 DOI: 10.1063/1.4914170] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
It is widely accepted that the Poisson-Boltzmann (PB) theory provides a valid description for charged surfaces in the so-called weak coupling limit. Here, we show that the image charge repulsion creates a depletion boundary layer that cannot be captured by a regular perturbation approach. The correct weak-coupling theory must include the self-energy of the ion due to the image charge interaction. The image force qualitatively alters the double layer structure and properties, and gives rise to many non-PB effects, such as nonmonotonic dependence of the surface energy on concentration and charge inversion. In the presence of dielectric discontinuity, there is no limiting condition for which the PB theory is valid.
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Affiliation(s)
- Rui Wang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Zhen-Gang Wang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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34
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Michler D, Shahidzadeh N, Westbroek M, van Roij R, Bonn D. Are antagonistic salts surfactants? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:906-911. [PMID: 25547006 DOI: 10.1021/la504801g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
It is well known that surfactants decrease both water/air and water/oil interfacial tensions whereas in contrast inorganic salts increase both. We study a new, third class of surface-active ionic solutes, which have been called antagonistic salts, consisting of an organic group with a small inorganic counterion. These show decreased interfacial tension at the oil/water interface due to a redistribution of the organic group in the oil but do not show any surface activity at the air/water interface and are consequently different from surfactants that lower both tensions. We use a simple modeling using Poisson-Boltzmann theory that accounts for the surface activity of the antagonistic salt at the water/oil interface.
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Affiliation(s)
- Dominik Michler
- van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands
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35
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Ma M, Xu Z. Self-consistent field model for strong electrostatic correlations and inhomogeneous dielectric media. J Chem Phys 2014; 141:244903. [DOI: 10.1063/1.4904728] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Manman Ma
- Department of Mathematics, Institute of Natural Sciences, and MoE Key Laboratory of Scientific and Engineering Computing, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhenli Xu
- Department of Mathematics, Institute of Natural Sciences, and MoE Key Laboratory of Scientific and Engineering Computing, Shanghai Jiao Tong University, Shanghai 200240, China
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36
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Bastea S. A simulation assessment of the thermodynamics of dense ion-dipole mixtures with polarization. J Chem Phys 2014; 141:044507. [PMID: 25084926 DOI: 10.1063/1.4890869] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Molecular dynamics (MD) simulations are employed to ascertain the relative importance of various electrostatic interaction contributions, including induction interactions, to the thermodynamics of dense, hot ion-dipole mixtures. In the absence of polarization, we find that an MD-constrained free energy term accounting for the ion-dipole interactions, combined with well tested ionic and dipolar contributions, yields a simple, fairly accurate free energy form that may be a better option for describing the thermodynamics of such mixtures than the mean spherical approximation (MSA). Polarization contributions induced by the presence of permanent dipoles and ions are found to be additive to a good approximation, simplifying the thermodynamic modeling. We suggest simple free energy corrections that account for these two effects, based in part on standard perturbative treatments and partly on comparisons with MD simulation. Even though the proposed approximations likely need further study, they provide a first quantitative assessment of polarization contributions at high densities and temperatures and may serve as a guide for future modeling efforts.
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Affiliation(s)
- Sorin Bastea
- Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550, USA
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37
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Xu Z, Ma M, Liu P. Self-energy-modified Poisson-Nernst-Planck equations: WKB approximation and finite-difference approaches. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:013307. [PMID: 25122410 DOI: 10.1103/physreve.90.013307] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Indexed: 06/03/2023]
Abstract
We propose a modified Poisson-Nernst-Planck (PNP) model to investigate charge transport in electrolytes of inhomogeneous dielectric environment. The model includes the ionic polarization due to the dielectric inhomogeneity and the ion-ion correlation. This is achieved by the self energy of test ions through solving a generalized Debye-Hückel (DH) equation. We develop numerical methods for the system composed of the PNP and DH equations. Particularly, toward the numerical challenge of solving the high-dimensional DH equation, we developed an analytical WKB approximation and a numerical approach based on the selective inversion of sparse matrices. The model and numerical methods are validated by simulating the charge diffusion in electrolytes between two electrodes, for which effects of dielectrics and correlation are investigated by comparing the results with the prediction by the classical PNP theory. We find that, at the length scale of the interface separation comparable to the Bjerrum length, the results of the modified equations are significantly different from the classical PNP predictions mostly due to the dielectric effect. It is also shown that when the ion self energy is in weak or mediate strength, the WKB approximation presents a high accuracy, compared to precise finite-difference results.
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Affiliation(s)
- Zhenli Xu
- Department of Mathematics, Institute of Natural Sciences, and MoE Key Lab of Scientific and Engineering Computing, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Manman Ma
- Department of Mathematics, Institute of Natural Sciences, and MoE Key Lab of Scientific and Engineering Computing, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Pei Liu
- Department of Mathematics, Institute of Natural Sciences, and MoE Key Lab of Scientific and Engineering Computing, Shanghai Jiao Tong University, Shanghai 200240, China
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38
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Guerrero García GI, Olvera de la Cruz M. Polarization Effects of Dielectric Nanoparticles in Aqueous Charge-Asymmetric Electrolytes. J Phys Chem B 2014; 118:8854-62. [DOI: 10.1021/jp5045173] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Guillermo Iván Guerrero García
- Department of Materials Science and Engineering, and ‡Department of
Chemical and Biological
Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Monica Olvera de la Cruz
- Department of Materials Science and Engineering, and ‡Department of
Chemical and Biological
Engineering, Northwestern University, Evanston, Illinois 60208, United States
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39
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Lu BS, Xing X. Correlation potential of a test ion near a strongly charged plate. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:032305. [PMID: 24730840 DOI: 10.1103/physreve.89.032305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Indexed: 06/03/2023]
Abstract
We analytically calculate the correlation potential of a test ion near a strongly charged plate inside a dilute m:-n electrolyte. We do this by calculating the electrostatic Green's function in the presence of a nonlinear background potential, the latter having been obtained using the nonlinear Poisson-Boltzmann theory. We consider the general case where the dielectric constants of the plate and the electrolyte are distinct. The following generic results emerge from our analyses: (1) If the distance to the plate Δz is much larger than a Gouy-Chapman length, the plate surface will behave effectively as an infinitely charged surface, and the dielectric constant of the plate effectively plays no role. (2) If Δz is larger than a Gouy-Chapman length but shorter than a Debye length, the correlation potential can be interpreted in terms of an image charge that is three times larger than the source charge. This behavior is independent of the valences of the ions. (3) The Green's function vanishes inside the plate if the surface charge density is infinitely large; hence the electrostatic potential is constant there. In this respect, a strongly charged plate behaves like a conductor plate. (4) If Δz is smaller than a Gouy-Chapman length, the correlation potential is dominated by the conventional image charge due to the dielectric discontinuity at the interface. (5) If Δz is larger than a Debye length, the leading order behavior of the correlation potential will depend on the valences of the ions in the electrolyte. Furthermore, inside an asymmetric electrolyte, the correlation potential is singly screened, i.e., it undergoes exponential decay with a decay width equal to the Debye length.
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Affiliation(s)
- Bing-Sui Lu
- Department of Physics and Astronomy, and Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiangjun Xing
- Department of Physics and Astronomy, and Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China
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40
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Buyukdagli S, Ala-Nissila T. Electrostatic correlations on the ionic selectivity of cylindrical membrane nanopores. J Chem Phys 2014; 140:064701. [DOI: 10.1063/1.4864323] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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41
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Guerrero-García GI, González-Mozuelos P, Olvera de la Cruz M. Large counterions boost the solubility and renormalized charge of suspended nanoparticles. ACS NANO 2013; 7:9714-9723. [PMID: 24180597 DOI: 10.1021/nn404477b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Colloidal particles are ubiquitous in biology and in everyday products such as milk, cosmetics, lubricants, paints, or drugs. The stability and aggregation of colloidal suspensions are of paramount importance in nature and in diverse nanotechnological applications, including the fabrication of photonic materials and scaffolds for biological assemblies, gene therapy, diagnostics, targeted drug delivery, and molecular labeling. Electrolyte solutions have been extensively used to stabilize and direct the assembly of colloidal particles. In electrolytes, the effective electrostatic interactions among the suspended colloids can be changed over various length scales by tuning the ionic concentration. However, a major limitation is gelation or flocculation at high salt concentrations. This is explained by classical theories, which show that the electrostatic repulsion among charged colloids is significantly reduced at high electrolyte concentrations. As a result, these screened colloidal particles are expected to aggregate due to short-range attractive interactions or dispersion forces as the salt concentration increases. We discuss here a robust, tunable mechanism for colloidal stability by which large counterions prevent highly charged nanoparticles from aggregating in salt solutions with concentrations up to 1 M. Large counterions are shown to generate a thicker ionic cloud in the proximity of each charged colloid, which strengthens short-range repulsions among colloidal particles and also increases the corresponding renormalized colloidal charge perceived at larger separation distances. These effects thus provide a reliable stabilization mechanism in a broad range of biological and synthetic colloidal suspensions.
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42
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Démery V, Dean DS, Podgornik R. Electrostatic interactions mediated by polarizable counterions: weak and strong coupling limits. J Chem Phys 2013; 137:174903. [PMID: 23145746 DOI: 10.1063/1.4763986] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We investigate the statistical mechanics of an inhomogeneous Coulomb fluid composed of charged particles with static polarizability. We derive the weak- and the strong-coupling approximations and evaluate the partition function in a planar dielectric slab geometry with charged boundaries. We investigate the density profiles and the disjoining pressure for both approximations. Comparison to the case of non-polarizable counterions shows that polarizability brings important differences in the counterion density distribution as well as the counterion mediated electrostatic interactions between charged dielectric interfaces.
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Affiliation(s)
- Vincent Démery
- Institut Jean Le Rond d'Alembert, CNRS and UPMC Université Paris 6, UMR 7190, F-75005 Paris, France
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43
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Guerrero-García GI, Olvera de la Cruz M. Inversion of the Electric Field at the Electrified Liquid–Liquid Interface. J Chem Theory Comput 2012; 9:1-7. [DOI: 10.1021/ct300673m] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
| | - Mónica Olvera de la Cruz
- Department of Materials
Science,
Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemical Engineering,
Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern
University, Evanston, Illinois 60208, United States
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44
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Diehl A, dos Santos AP, Levin Y. Surface tension of an electrolyte-air interface: a Monte Carlo study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:284115. [PMID: 22739036 DOI: 10.1088/0953-8984/24/28/284115] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a new method for calculating the surface tension of an electrolyte-air interface using Monte Carlo (MC) simulations with an implicit solvent in a spherical drop geometry. The boundary conditions for the electric field at the interface are accounted for using image and counter-image charges. The density profiles obtained from the simulations are used to calculate the excess surface tension of the electrolyte-air interface using the Gibbs adsorption isotherm equation. The results are found to be in good agreement with experiments and the earlier theoretical calculations.
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Affiliation(s)
- Alexandre Diehl
- Departamento de Física, Instituto de Física e Matemática, Universidade Federal de Pelotas, Caixa Postal 354, CEP 96010-900, Pelotas, RS, Brazil
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45
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Wang ZY, Ma YQ. Computational evidence of two driving mechanisms for overcharging in an electric double layer near the point of zero charge. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:062501. [PMID: 23005151 DOI: 10.1103/physreve.85.062501] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 03/26/2012] [Indexed: 06/01/2023]
Abstract
We have adopted an ensemble Monte Carlo simulation method to systematically verify two physical driving mechanisms responsible for overcharging which refers to the adsorption of an effective charge onto a like-charged planar surface around the point of zero charge within the primitive model of mixed electrolytes with varying salt concentrations. One is electrostatic in character dominated by dielectric images and the other is purely entropic in origin by ionic size asymmetry effects, of which the former has never been reported both theoretically and experimentally and the latter could be interpreted satisfactorily in terms of available theoretical approaches. The electrostatically driven mechanism is found to critically depend on the ionic sizes while the entropically driven mechanism occurs with almost the same efficiency in a relative wide range of surface charge density. Depending on the delicate interplay between charge and steric correlations, the two distinct driving mechanisms may cooperatively give rise to a more pronounced overcharging process.
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Affiliation(s)
- Zhi-Yong Wang
- School of Optoelectronic Information, Chongqing University of Technology, Chongqing 400054, China.
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46
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Colla TE, dos Santos AP, Levin Y. Equation of state of charged colloidal suspensions and its dependence on the thermodynamic route. J Chem Phys 2012; 136:194103. [DOI: 10.1063/1.4718367] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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47
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Cahill K. Models of membrane electrostatics. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:051921. [PMID: 23004801 DOI: 10.1103/physreve.85.051921] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 04/09/2012] [Indexed: 06/01/2023]
Abstract
Formulas are derived for the electrostatic potential of a charge in or near a membrane modeled as one or more dielectric slabs lying between two semi-infinite dielectrics. One can use these formulas in Monte Carlo codes to compute the distribution of ions near cell membranes more accurately than by using Poisson-Boltzmann theory or its linearized version. Here I use them to discuss the electric field of a uniformly charged membrane, the image charges of an ion, the distribution of salt ions near a charged membrane, the energy of a zwitterion near a lipid slab, and the effect of including the phosphate head groups as thin layers of high electric permittivity.
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Affiliation(s)
- Kevin Cahill
- Biophysics Group, Department of Physics & Astronomy, University of New Mexico, Albuquerque, New Mexico 87131, USA.
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48
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Lue L, Linse P. Macroion solutions in the cell model studied by field theory and Monte Carlo simulations. J Chem Phys 2012; 135:224508. [PMID: 22168704 DOI: 10.1063/1.3665450] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Aqueous solutions of charged spherical macroions with variable dielectric permittivity and their associated counterions are examined within the cell model using a field theory and Monte Carlo simulations. The field theory is based on separation of fields into short- and long-wavelength terms, which are subjected to different statistical-mechanical treatments. The simulations were performed by using a new, accurate, and fast algorithm for numerical evaluation of the electrostatic polarization interaction. The field theory provides counterion distributions outside a macroion in good agreement with the simulation results over the full range from weak to strong electrostatic coupling. A low-dielectric macroion leads to a displacement of the counterions away from the macroion.
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Affiliation(s)
- Leo Lue
- Department of Chemical and Process Engineering, University of Strathclyde James Weir Building, 75 Montrose Street, Glasgow G1 1XJ, United Kingdom.
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Su J, de la Cruz MO, Guo H. Solubility and transport of cationic and anionic patterned nanoparticles. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:011504. [PMID: 22400574 DOI: 10.1103/physreve.85.011504] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 01/05/2012] [Indexed: 05/31/2023]
Abstract
We analyze bulk diffusion and transport through hydrophobic nanochannels of nanoparticles (NPs) with different hydrophobic-hydrophilic patterns achieved by coating a fraction of the NP sites with positive or negative charges via explicit solvent molecular dynamics simulations. Ten different charge pattern types including Janus charged-hydrophobic NPs are studied. The cationic NPs are more affected by the patterns and have higher diffusion constants and fluxes than their anionic NPs counterparts. The NP-water interaction dependence on surface pattern and field strength explains these observations. The NP-water Coulomb interaction of anionic NPs in the bulk, which are much stronger than the hydrophobic NP-water interactions, are stronger for NPs with higher localized charge, and stronger than in the cationic NPs counterparts. The diffusion and transport of anionic NPs such as proteins and protein charge ladders with the same total charge but different surface charge patterns are slowest for the highest localized charge pattern, which also adsorb strongest onto surfaces. Our model demonstrates the separation (by reverse osmosis, capillary electrophoresis, or chromatography) of cationic NPs, including proteins with equal net charge but different surface charge distributions.
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Affiliation(s)
- Jiaye Su
- Beijing National Laboratory for Molecular Sciences, Chinese Academy of Sciences, Beijing 100190, China
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Guerrero-García GI, González-Mozuelos P, de la Cruz MO. Potential of mean force between identical charged nanoparticles immersed in a size-asymmetric monovalent electrolyte. J Chem Phys 2011; 135:164705. [DOI: 10.1063/1.3656763] [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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