Introduction to colloidal dispersions in external fields

Löwen, Hartmut

doi:10.1140/epjst/e2013-02054-3

Cited by 29 publications

(33 citation statements)

References 84 publications

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“…Therefore, they may be easily shear-melted by slight mechanical disturbance e.g., by simple shaking. Manipulation of colloidal solids by external fields is very effective, offering possibilities to control the colloidal micro-structure upon re-crystallization, as well as the formation and re-juvenation of colloidal glasses [17,38,39,40,41].…”

Section: Introductionmentioning

confidence: 99%

To make a glass—avoid the crystal

Palberg¹,

Bartsch²,

Beyer³

et al. 2016

J. Stat. Mech.

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Colloidal model systems allow for a flexible tuning of particle sizes, particle spacings and mutual interactions at constant temperature. Colloidal suspensions typically crystallize as soon as the interactions get sufficiently strong and long-ranged. Several strategies have been successfully applied to avoid crystallization and instead produce colloidal glasses. Most of these amorphous solids are formed at high particle concentrations. This paper shortly reviews experimental attempts to produce amorphous colloidal solids using strategies based on topological, thermodynamic and kinetic considerations. We complement this overview by introducing a (transient) amorphous solid forming in a thoroughly deionized aqueous suspension of highly charged spheres at low salt concentration and very low volume fractions.

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Section: Introductionmentioning

confidence: 99%

To make a glass—avoid the crystal

Palberg¹,

Bartsch²,

Beyer³

et al. 2016

J. Stat. Mech.

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“…Nonequilibrium systems often show emergence of structural heterogeneity in steady states, known as pattern formation [5] relevant in areas ranging from material science to biological systems [3,4]. The particle dynamics in such systems is nontrivial due to drive [6][7][8][9]. Despite large number of studies [3][4][5][6][7][8][9], the connections between dynamics and structure, and consequently, the transport processes are not well understood for non-equilibrium situations.…”

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confidence: 99%

Anomalous dynamical responses in a driven system

Dutta

Chakrabarti

2016

EPL

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The interplay between structure and dynamics in non-equilibrium steady-state is far from understood. We address this interplay by tracking Brownian Dynamics trajectories of particles in a binary colloid of opposite charges in an external electric field, undergoing cross-over from homogeneous to lane state, a prototype of heterogeneous structure formation in non-equilibrium systems. We show that the length scale of structural correlations controls heterogeneity in diffusion and consequent anomalous dynamic responses, like the exponential tail in probability distributions of particle displacements and stretched exponential structural relaxation. We generalise our observations using equations for steady state density which may aid to understand microscopic basis of heterogeneous diffusion in condensed matter systems. The dynamic response depicts how disturbance in any thermodynamic quantity in a system relaxes with time via particle motion [1,2]. This forms the microscopic basis of transport processes [1][2][3][4], like diffusion in liquids. In general particle dynamics depends on the structure of the system. Nonequilibrium systems often show emergence of structural heterogeneity in steady states, known as pattern formation [5] relevant in areas ranging from material science to biological systems [3,4]. The particle dynamics in such systems is nontrivial due to drive [6][7][8][9]. Despite large number of studies [3][4][5][6][7][8][9], the connections between dynamics and structure, and consequently, the transport processes are not well understood for non-equilibrium situations. This motivates us to explore dynamic responses and relate them to the underlying structural morphology in non-equilibrium steady states.Colloids are ideal model system to realize condensed matter properties both in and out of equilibrium [3,4,6,7]. Variety of structures can be induced in colloids by external perturbations [3,4,[6][7][8][9]. Moreover, the particles are big enough for optical imaging and are slow so that the particle motions can be followed [1][2][3][4][6][7][8][9]. Several experiments and theoretical works show that in an external uniform electric field of large strength drives a binary mixture of oppositely charged colloids to form heterogeneous structure in the steady state with lanes of dynamically locked-in like-charged particles, while the mixture is homogeneous at low field [3,4,[6][7][8][9][10][11][12][13][14][15][16].We consider steady states of binary charged colloid in electric field. The steady state structural correlations are given by the pair correlation functions(PCF) [1] which are probability distributions of particle separations at a given time. We study how density changes relax via microscopic motion in * Electronic address: Email:sumand@bose.res.in † Electronic address: Email:jaydeb@bose.res.in different steady state structures of binary charged colloid in electric field. The density relaxation, also known as the van Hove function (vHf) [17], is measurable from scattering experiments and routinely used in ...

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“…In this paper, we will consider the case of electromagnetic fields. They not only help to control the rotational degrees of freedom [23] or fine tune the particle-particle interactions [21,22,24], but they can also act as virtual molds to induce spatial periodic patterns [25][26][27], as we discuss below.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Design of Spatial Patterns of Colloidal Suspensions

2017

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We study the collective dynamics of colloidal suspensions in the presence of a time-dependent potential by means of dynamic density functional theory. We consider a nonlinear diffusion equation for the density and show that spatial patterns emerge from a sinusoidal external potential with a time-dependent wavelength. These patterns are characterized by a sinusoidal density with the average wavelength and a Bessel-function envelope with an induced wavelength that depends only on the amplitude of the temporal oscillations. As a generalization of this result, we propose a design strategy to obtain a family of spatial patterns using time-dependent potentials of practically arbitrary shape.

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Introduction to colloidal dispersions in external fields

Cited by 29 publications

References 84 publications

To make a glass—avoid the crystal

To make a glass—avoid the crystal

Anomalous dynamical responses in a driven system

Dynamic Design of Spatial Patterns of Colloidal Suspensions

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