Effective pair potential between charged nanoparticles at high volume fractions

Bareigts, Guillaume; Labbez, Christophe

doi:10.1039/c6cp08056a

Cited by 8 publications

(5 citation statements)

References 41 publications

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“…The choice of an accurate interaction potential of the general application for charged interfacial colloids is not a trivial task and has been the subject of a considerable number of theoretical and experimental studies. ,− Charged colloids at air–fluid or fluid–fluid interfaces are typically in contact with two environments of differing dielectric properties and electrolyte contents and are, in addition, affected by wetting and capillary stress. These aspects introduce specific features in the interactions between the colloids that add complexity with respect to the analogous interactions in the bulk of a solution. ,− …”

Section: Methodsmentioning

confidence: 99%

Coadsorption of Counterionic Colloids at Fluid Interfaces: A Coarse-Grained Simulation Study of Gibbs Monolayers

2020

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Monolayers of oppositely charged colloids form versatile selforganizing substrates, with a recognized potential to tailor functional interfaces. In this study, a coarse-grained Monte Carlo simulation approach is laid out to assess the structural properties of Gibbs monolayers, in which one of the counterionic species is partially soluble. It is shown that the composition of this type of monolayer varies in a nontrivial way with surface coverage, as a result of a subtle competition between steric and attractive forces. In the regime of weak electrostatic interactions, the monolayer is depleted of soluble colloids as the surface coverage is increased. At sufficiently strong interactions, the incorporation of soluble colloids is favored at high surface coverage, leading to a re-entrant-type behavior in the expansion/compression isotherms. Strong electrostatic interactions also favor the clustering of the colloids, leading to a range of aggregated configurations, qualitatively resembling those obtained in previous experimental studies. At sufficiently high surface coverage, the clusters collapse into a gel-like percolated mesoscopic structure and eventually into a square crystal lattice configuration. Such interfacial structures are in good agreement with the ones observed in the few experimental investigations available for these systems, showing that the simple methodology introduced in this study provides a valuable predictive framework to anticipate the landscape of interfacial structures that may be produced with oppositely charged colloids, through the modulation of pair interactions and thermodynamical conditions.

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Section: Methodsmentioning

confidence: 99%

Coadsorption of Counterionic Colloids at Fluid Interfaces: A Coarse-Grained Simulation Study of Gibbs Monolayers

2020

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“…In our MD simulations, we use the restricted primitive model (RPM) , where the charged components interact via Coulomb and hard core interactions, which has successfully described both ionic and superionic gels . This is necessary because the Debye–Hückel (DH) approximation and other continuum theories cannot describe dense charged colloidal systems − and particularly fail to describe ionic compounds and ion-driven condensation . In the simulations, we kept the volume fraction of large NPs in the solution constant as 0.3.…”

Section: Introductionmentioning

confidence: 99%

Superionic Colloidal Crystals: Ionic to Metallic Bonding Transitions

Lin

Cruz

2022

J. Phys. Chem. B

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Size-asymmetric binary charged colloidal solutions can assemble into ionic colloidal crystals. These are often stabilized by ionic-type bonding, where the components with smaller size and charge sit at fixed points within the lattice of large particles. Here, we study the transition termed ionic to metallic bonding transition, by which the lattice of the smaller component melts while the crystal of the large particles is preserved, as in metallic bonding. We simulate a charged colloidal crystal in equilibrium with a solution containing small colloidal particles and counterions using the Coulomb interaction between the finite-size components. We find ionic to metallic first-order transitions by increasing either the temperature or the concentration of the small particles in the solution. The transition is accompanied by a lattice expansion and increased absorption of small particles into the crystal. We compute the free energies of the ionic and metallic states using the Madelung constant and Wigner–Seitz cell approaches, respectively, combined with the quasi-harmonic lattice model. The calculation reproduces the simulated transition and reveals that the enthalpic gain is more pronounced than the entropic gain in the transition from ionic to metallic bonding when material is exchanged with the solution.

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“…[1,2] A model system for studying EPD is the directed assembly of particle layers from solutions of chemically synthesized, monodisperse microspheres. [3,4] Research complexities of colloidal interactions [22][23][24] and can be experimentally extracted from video microscopy and particle tracking methods. [25][26][27][28] Here, we report on an approach to measure coarse-grained, effective interparticle potentials for glass microspheres on an electrode surface under the influence of DC-driven electrophoresis.…”

Section: Introductionmentioning

confidence: 99%

“…A simplified description of these behaviors in terms of an effective pair potential can capture the effects of the experimental parameters (particle density, electrode potential, solution composition) while encapsulating the underlying electrostatics and hydrodynamics of the electrolyte. Effective pair potentials are often used to simplify the underlying complexities of colloidal interactions [ 22–24 ] and can be experimentally extracted from video microscopy and particle tracking methods. [ 25–28 ]…”

Section: Introductionmentioning

confidence: 99%

Characterizing the Solvent‐Induced Inversion of Colloidal Aggregation During Electrophoretic Deposition

DeMoulpied

Killenbeck

Schichtl

et al. 2022

Adv Materials Inter

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Electrophoretic deposition (EPD) of colloidal particles is a practical system for the study of crystallization and related physical phenomena. The aggregation is driven by the electroosmotic flow fields and induced dipole moments generated by the polarization of the electrode‐particle‐electrolyte interface. Here, the electrochemical control of aggregation and repulsion in the electrophoretic deposition of colloidal microspheres is reported. The nature of the observed transition depended on the composition of the solvent, switching from electrode‐driven aggregation in water to electrical field‐driven repulsion in ethanol for otherwise identical systems of colloidal microspheres. This work uses optical microscopy‐derived particles and a recently developed particle insertion method approach to extract model‐free, effective interparticle potentials to describe the ensemble behavior of the particles as a function of the solvent and electrode potential at the electrode interface. This approach can be used to understand the phase behavior of these systems based on the observable particle positions rather than a detailed understanding of the electrode‐electrolyte microphysics. This approach enables simple predictability of the static and dynamic behaviors of functional colloid‐electrode interfaces.

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Effective pair potential between charged nanoparticles at high volume fractions

Cited by 8 publications

References 41 publications

Coadsorption of Counterionic Colloids at Fluid Interfaces: A Coarse-Grained Simulation Study of Gibbs Monolayers

Coadsorption of Counterionic Colloids at Fluid Interfaces: A Coarse-Grained Simulation Study of Gibbs Monolayers

Superionic Colloidal Crystals: Ionic to Metallic Bonding Transitions

Characterizing the Solvent‐Induced Inversion of Colloidal Aggregation During Electrophoretic Deposition

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