Effect of charge asymmetry and charge screening on structure of superlattices formed by oppositely charged colloidal particles

Pavaskar, Ganeshprasad; Sharma, Siddharth; Punnathanam, Sudeep N.

doi:10.1063/1.3700226

Cited by 13 publications

(9 citation statements)

References 34 publications

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“…This result suggests that these dissipative structures cannot be produced via equilibrium self-assembly. This conclusion is supported by previously measured and predicted phase diagrams of systems of oppositely charged particles in the absence of external fields, which do not contain dimers, high-aspect ratio fibers, or honeycomb lattices (4,19,20). Note that simulations of oppositely charged particles interacting through static Yukawa potentials show the formation of fibers shorter than those in Fig.…”

Section: Resultssupporting

confidence: 78%

Dissipative self-assembly of particles interacting through time-oscillatory potentials

Tagliazucchi¹,

Weiss²,

Szleifer

2014

Proc. Natl. Acad. Sci. U.S.A.

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Dissipative self-assembly is the emergence of order within a system due to the continuous input of energy. This form of nonequilibrium self-organization allows the creation of structures that are inaccessible in equilibrium self-assembly. However, design strategies for dissipative self-assembly are limited by a lack of fundamental understanding of the process. This work proposes a novel route for dissipative self-assembly via the oscillation of interparticle potentials. It is demonstrated that in the limit of fast potential oscillations the structure of the system is exactly described by an effective potential that is the time average of the oscillatory potential. This effective potential depends on the shape of the oscillations and can lead to effective interactions that are physically inaccessible in equilibrium. As a proof of concept, Brownian dynamics simulations were performed on a binary mixture of particles coated by weak acids and weak bases under externally controlled oscillations of pH. Dissipative steady-state structures were formed when the period of the pH oscillations was smaller than the diffusional timescale of the particles, whereas disordered oscillating structures were observed for longer oscillation periods. Some of the dissipative structures (dimers, fibers, and honeycombs) cannot be obtained in equilibrium (fixed pH) simulations for the same system of particles. The transition from dissipative self-assembled structures for fast oscillations to disordered oscillating structures for slow oscillations is characterized by a maximum in the energy dissipated per oscillation cycle. The generality of the concept is demonstrated in a second system with oscillating particle sizes.issipative or dynamic self-assembly is the formation of order due to the continuous input of energy into the system and dissipation of energy by the system into the environment (1). If the input of energy is stopped, dissipative structures are destroyed as the system evolves toward equilibrium; therefore, these structures exist only far from equilibrium. Dissipative self-assembled structures are unique due to their ability to adapt to environmental changes. Consider, for example, a school of fish where each individual dynamically interacts with its neighbors and adjusts its position and velocity accordingly (2). Due to its dynamical nature, the school of fish responds as a whole when a predator threatens one of its individuals. This complex behavior is impossible for a static assembly. Nature excels in using dissipative structures to minimize wasted energy. For example, a swarm of bees can change its size and density to regulate its internal temperature, and a flock of Canada geese reduces energy dissipation due to aerodynamic drag by flying in a V-shaped formation (2).Synthetic dissipative assemblies are restricted to a small number of examples, such as magnetic spinners at the air-water interface (1), magnetic droplets on surperhydrophobic surfaces (3), lanes of colloidal particles under the influence of external fields (4...

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Section: Resultssupporting

confidence: 78%

Dissipative self-assembly of particles interacting through time-oscillatory potentials

Tagliazucchi¹,

Weiss²,

Szleifer

2014

Proc. Natl. Acad. Sci. U.S.A.

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“…The heteroaggregation of colloids with moderate or small size mismatch has been extensively studied, with many efforts aiming at elucidating formation pathways and properties of colloidal crystals [2,3,[6][7][8]29,[51][52][53][54][55][56][57][58][59]. In the following we focus on the studies concerning ceramic colloids [16,17,23,24,26,28,31].…”

Section: Heterocolloids With Moderate and Small Size Mismatchmentioning

confidence: 99%

Heteroaggregation of ceramic colloids in suspensions

Cerbelaud

Videcoq

Rossignol

et al. 2016

Advances in Physics: X

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The colloidal route is an important methodology in ceramic processing. A key step of the colloidal route is the aggregation of colloids in suspension. This often involves colloids of different types, in a process which is known as heteroaggregation. Here we review the recent developments in ceramic heteroaggregation, focusing on the physical mechanisms that cause it and on the structural properties of the resulting aggregates. Structural properties are analysed both on the local scale, at the level of nearest-neighbour contacts between colloids and on the long-range scale, at which percolating aggregates form, leading to gelification. Both experimental and simulation results are reviewed. The effects of the structure of the aggregates on the subsequent steps of ceramic processing are discussed

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“…From the theoretical/computational point of view, notable attention has been devoted both to the determination of the equilibrium properties of binary suspensions [2,7,10,11], with the calculation of phase diagrams of representative model systems, and to their aggregation kinetics [2,7,[12][13][14]. However, several aspects of heteroaggregation are still to be understood, especially for what concerns the basic mechanisms that determine the structures obtained in the actual aggregation processes.…”

Section: Introductionmentioning

confidence: 99%

Kinetically driven ordered phase formation in binary colloidal crystals

2013

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The aggregation of binary colloids of same size and balanced charges is studied by Brownian dynamics simulations for dilute suspensions. It is shown that, under appropriate conditions, the formation of colloidal crystals is dominated by kinetic effects leading to the growth of well-ordered crystallites of the sodium-chloride (NaCl) bulk phase. These crystallites form with very high probability even when the cesium-chloride (CsCl) phase is more stable thermodynamically. Global optimization searches show that this result is not related to the most favorable structures of small clusters, that are either amorphous or of CsCl structure. The formation of the NaCl phase is related to the specific kinetics of the crystallization process, which takes place by a two-step mechanism. In this mechanism, dense fluid aggregates form at first and then crystallization follows. It is shown that the type of short-range order in these dense fluid aggregates determines which phase is finally formed in the crystallites. The role of hydrodynamic effects in the aggregation process is analyzed by Stochastic Rotation Dynamics -Molecular Dynamics simulations, finding that these effects do not play a major role in the formation of the crystallites.

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Effect of charge asymmetry and charge screening on structure of superlattices formed by oppositely charged colloidal particles

Cited by 13 publications

References 34 publications

Dissipative self-assembly of particles interacting through time-oscillatory potentials

Dissipative self-assembly of particles interacting through time-oscillatory potentials

Heteroaggregation of ceramic colloids in suspensions

Kinetically driven ordered phase formation in binary colloidal crystals

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