Two-dimensional colloidal mixtures in magnetic and gravitational fields

Löwen, Hartmut; Horn, Tobias; Neuhaus, Tim; Hagen, Borge ten

doi:10.1140/epjst/e2013-02069-8

Cited by 10 publications

(9 citation statements)

References 76 publications

(94 reference statements)

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“…In principle, our DFT calculations can be extended to describe the orderings of particles in gravity [89,90] or of particles possessing charges [91], which might be confined by charged surfaces [92]. Such extensions lead to systems with many important applications, e.g., the formation and in-plane structure of electric double layers [93] or interfaces like the liquid-vapor one [5].…”

Section: Discussionmentioning

confidence: 99%

Anisotropic pair correlations in binary and multicomponent hard-sphere mixtures in the vicinity of a hard wall: A combined density functional theory and simulation study

2015

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The fundamental measure approach to classical density functional theory has been shown to be a powerful tool to predict various thermodynamic properties of hard-sphere systems. We employ this approach to determine not only one-particle densities but also two-particle correlations in binary and six-component mixtures of hard spheres in the vicinity of a hard wall. The broken isotropy enables us to carefully test a large variety of theoretically predicted two-particle features by quantitatively comparing them to the results of Brownian dynamics simulations. Specifically, we determine and compare the one-particle density, the total correlation functions, their contact values, and the force distributions acting on a particle. For this purpose, we follow the compressibility route and theoretically calculate the direct correlation functions by taking functional derivatives. We usually observe an excellent agreement between theory and simulations, except for small deviations in cases where local crystal-like order sets in. Our results set the course for further investigations on the consistency of functionals as well as for structural analysis on, e.g., the primitive model. In addition, we demonstrate that due to the suppression of local crystallization, the predictions of six-component mixtures are better than those in bidisperse or monodisperse systems. Finally, we are confident that our results of the structural modulations induced by the wall lead to a deeper understanding of ordering in anisotropic systems in general, the onset of heterogeneous crystallization, caging effects and glassy dynamics close to a wall, as well as structural properties in systems with confinement.

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Section: Discussionmentioning

confidence: 99%

Anisotropic pair correlations in binary and multicomponent hard-sphere mixtures in the vicinity of a hard wall: A combined density functional theory and simulation study

2015

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“…Various aspects of the impact of magnetic fields on colloids is intensely discussed in five minireviews of this special issue: The motion of magnetic particles in external potential barriers [48] and in time-dependent magnetic fields [49], the superposition of a magnetic field with shear flow [50] and gravity [51] and the extension from onecomponent systems to binary mixtures [51].…”

Section: Laser-optical and Magnetic Fieldsmentioning

confidence: 99%

Introduction to colloidal dispersions in external fields

Löwen

2013

Eur. Phys. J. Spec. Top.

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Progress in the research area of colloidal dispersions in external fields within the last years is reviewed. Colloidal dispersions play a pivotal role as model systems for phase transitions in classical statistical mechanics. In recent years the leading role of colloids to realize model systems has become evident not only for equilibrium situations but also far away from equilibrium. By using external fields (such as shear flow, electric, magnetic or laseroptical fields as well as confinement), a colloidal suspension can be brought into nonequilibrium in a controlled way. Various kinds of equilibrium and nonequilibrium phenomena explored by colloidal dispersions are described providing also a guide and summary to this special issue. Particular emphasis is put on the comparison of real-space experiments, computer simulations and statistical theories.

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“…Other types of regular arrangements, for instancewith periodic square or rhombic symmetry, are, in principle, possible [5], but in real experiments they are typically encountered over tiny areas [6,7]. More often, if the more ordered and regular hexagonal symmetry is not observed, more amorphous and disordered patterns can be generated, in which L particles lose the hexagonal symmetry and show a coexistence of different symmetries, e.g., hexagonal, square and rhombic phases, geometries of transition between the different symmetries, random tiling [5,8,9,10,11,12]. In some cases, segregation of S and L particles can even occur in which S and L particles separately assemble in areas with hexagonal symmetry [2,5,13].…”

Section: Introductionmentioning

confidence: 99%

A Journey Through the Landscapes of Small Particles in Binary Colloidal Assemblies: Unveiling Structural Transitions from Isolated Particles to Clusters upon Variation in Composition

Lotito

Zambelli

2019

Nanomaterials

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Two-dimensional (2D) amorphous binary colloidal assemblies composed of particles of two different sizes are characterized by the loss of hexagonal close-packing for larger particles, occurring when the size ratio between small (S) and large (L) particles dSdL exceeds a certain threshold value. For moderately low particle number ratios NSNL large particles still retain a denser arrangement with transitions from hexagonal symmetry to the coexistence of different types of symmetries as NSNL progressively departs from 0 to higher values. On the other hand, small particles reveal sparser arrangements: shape identification and quantification of structural transitions in small particle arrangements appear particularly challenging. In this article, we investigate their shapes and transitions for amorphous binary colloidal particles assembled at the air/water interface. For the quantitative characterization of the evolution in particle arrangements for NSNL variable between 0.5 and 2, we develop an innovative procedure for morphological analysis, combining Minkowski functionals, Voronoi diagrams and ad hoc techniques to recognize and classify specific features. Such a powerful approach has revealed a wide variety of landscapes featuring isolated particles, dimers, chains, small clusters evolving with the colloidal suspension composition. Our method can be applied to the analysis of spatial configurations of sparse colloidal patterns obtained in different conditions.

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Two-dimensional colloidal mixtures in magnetic and gravitational fields

Cited by 10 publications

References 76 publications

Anisotropic pair correlations in binary and multicomponent hard-sphere mixtures in the vicinity of a hard wall: A combined density functional theory and simulation study

Anisotropic pair correlations in binary and multicomponent hard-sphere mixtures in the vicinity of a hard wall: A combined density functional theory and simulation study

Introduction to colloidal dispersions in external fields

A Journey Through the Landscapes of Small Particles in Binary Colloidal Assemblies: Unveiling Structural Transitions from Isolated Particles to Clusters upon Variation in Composition

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