Impurity Partitioning During Colloidal Crystallization

Nozawa, Jun; Uda, Satoshi; Naradate, Yuhei; Koizumi, Hideaki; Fujiwara, Kozo; Toyotama, Akiko; Yamanaka, Junpei

doi:10.1021/jp309550y

Cited by 20 publications

(24 citation statements)

References 33 publications

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“…Remaining seeds then are either distributed throughout the sample or populate the grain boundaries of the emerging crystals. Their accumulation there is assisted by annealing processes [81,365] and a foam-like microstructure appears similar to that observed for long lasting annealing of AS crystals [298,299]. Cleaning of contaminated crystals can be achieved by processes analogous to zone melting [366].…”

Section: Heterogeneous Nucleationmentioning

confidence: 80%

Crystallization kinetics of colloidal model suspensions: recent achievements and new perspectives

Palberg

2014

J. Phys.: Condens. Matter

129

132

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Colloidal model systems allow studying crystallization kinetics under fairly ideal conditions, with rather well-characterized pair interactions and minimized external influences. In complementary approaches experiment, analytic theory and simulation have been employed to study colloidal solidification in great detail. These studies were based on advanced optical methods, careful system characterization and sophisticated numerical methods. Over the last decade, both the effects of the type, strength and range of the pair-interaction between the colloidal particles and those of the colloid-specific polydispersity have been addressed in a quantitative way. Key parameters of crystallization have been derived and compared to those of metal systems. These systematic investigations significantly contributed to an enhanced understanding of the crystallization processes in general. Further, new fundamental questions have arisen and (partially) been solved over the last decade: including, for example, a two-step nucleation mechanism in homogeneous nucleation, choice of the crystallization pathway, or the subtle interplay of boundary conditions in heterogeneous nucleation. On the other hand, via the application of both gradients and external fields the competition between different nucleation and growth modes can be controlled and the resulting microstructure be influenced. The present review attempts to cover the interesting developments that have occurred since the turn of the millennium and to identify important novel trends, with particular focus on experimental aspects.

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Section: Heterogeneous Nucleationmentioning

confidence: 80%

Crystallization kinetics of colloidal model suspensions: recent achievements and new perspectives

Palberg

2014

J. Phys.: Condens. Matter

129

132

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“…Nucleation needs seconds to minutes [29], growth needs some minutes to a few hours for completing the phase transformations [14,30]. Coarsening occurs within a few days at room temperature [31,32]. These highly correlated systems become widely recognized as model systems for condensed matter physics.…”

Section: Ducting Materials If the Eriences A Timementioning

confidence: 99%

Overview: Experimental studies of crystal nucleation: Metals and colloids

Herlach

Palberg

Klassen

et al. 2016

The Journal of Chemical Physics

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Crystallization is one of the most important phase transformations of first order. In the case of metals and alloys, the liquid phase is the parent phase of materials production. The conditions of the crystallization process control the as-solidified material in its chemical and physical properties. Nucleation initiates the crystallization of a liquid. It selects the crystallographic phase, stable or meta-stable. Its detailed knowledge is therefore mandatory for the design of materials. We present techniques of containerless processing for nucleation studies of metals and alloys. Experimental results demonstrate the power of these methods not only for crystal nucleation of stable solids but in particular also for investigations of crystal nucleation of metastable solids at extreme undercooling. This concerns the physical nature of heterogeneous versus homogeneous nucleation and nucleation of phases nucleated under non-equilibrium conditions. The results are analyzed within classical nucleation theory that defines the activation energy of homogeneous nucleation in terms of the interfacial energy and the difference of Gibbs free energies of solid and liquid. The interfacial energy acts as barrier for the nucleation process. Its experimental determination is difficult in the case of metals. In the second part of this work we therefore explore the potential of colloidal suspensions as model systems for the crystallization process. The nucleation process of colloids is observed in situ by optical observation and ultra-small angle X-ray diffraction using high intensity synchrotron radiation. It allows an unambiguous discrimination of homogeneous and heterogeneous nucleation as well as the determination of the interfacial free energy of the solid-liquid interface. Our results are used to construct Turnbull plots of colloids, which are discussed in relation to Turnbull plots of metals and support the hypothesis that colloids are useful model systems to investigate crystal nucleation.

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“…We have already reported that the impurity particles were excluded from the crystals to the grain boundaries during grain growth in charged colloids 10 . Nozawa et al have studied the impurity distribution in charged colloids based on the crystallization theory 33 . A similar exclusion behavior was observed for the present crystallization ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Spontaneous Formation of Eutectic Crystal Structures in Binary and Ternary Charged Colloids due to Depletion Attraction

Toyotama

Okuzono

Yamanaka

2016

Sci Rep

Self Cite

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Crystallization of colloids has extensively been studied for past few decades as models to study phase transition in general. Recently, complex crystal structures in multi-component colloids, including alloy and eutectic structures, have attracted considerable attention. However, the fabrication of 2D area-filling colloidal eutectics has not been reported till date. Here, we report formation of eutectic structures in binary and ternary aqueous colloids due to depletion attraction. We used charged particles + linear polyelectrolyte systems, in which the interparticle interaction could be represented as a sum of the electrostatic, depletion, and van der Waals forces. The interaction was tunable at a lengthscale accessible to direct observation by optical microscopy. The eutectic structures were formed because of interplay of crystallization of constituent components and accompanying fractionation. An observed binary phase diagram, defined by a mixing ratio and inverse area fraction of the particles, was analogous to that for atomic and molecular eutectic systems. This new method also allows the adjustment of both the number and wavelengths of Bragg diffraction peaks. Furthermore, these eutectic structures could be immobilized in polymer gel to produce self-standing materials. The present findings will be useful in the design of the optical properties of colloidal crystals.

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Impurity Partitioning During Colloidal Crystallization

Cited by 20 publications

References 33 publications

Crystallization kinetics of colloidal model suspensions: recent achievements and new perspectives

Crystallization kinetics of colloidal model suspensions: recent achievements and new perspectives

Overview: Experimental studies of crystal nucleation: Metals and colloids

Spontaneous Formation of Eutectic Crystal Structures in Binary and Ternary Charged Colloids due to Depletion Attraction

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