Kinetic Analyses of the Colloidal Crystallization of Silica Spheres As Studied by Reflection Spectroscopy

Okubo, Tsuneo; Okada, Shusuke

doi:10.1006/jcis.1997.5028

Cited by 22 publications

(24 citation statements)

References 32 publications

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“…This provides support that the degree of deionization of the sample suspensions in this work is quite low, similar to the level in the previous work. It should be recalled that the crystallization rates are quite sensitive to the ionic concentration of the suspension and decrease sharply as ionic concentration increases (25). It should be mentioned here that the crystals formed in the presence of electric fields and in their absence had a mean size of 139 m and were quite insensitive to the electric field strength applied.…”

Section: Electric Field Strength Dependencementioning

confidence: 97%

“…The crystallization process was unexpectedly fast. In the previous papers (24,25), nucleation rates in aqueous media increased drastically as sphere concentration increased. Crystal growth rates also increased substantially as sphere concentration increased.…”

Section: Introductionmentioning

confidence: 96%

“…We have studied the nucleation and crystallization processes in exhaustively deionized and highly diluted aqueous suspensions from the sharpening of the reflection peak in reflection spectroscopy (15,19,24,25). The crystallization process was unexpectedly fast.…”

Section: Introductionmentioning

confidence: 98%

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Kinetic Analyses of Colloidal Crystallization in a Sinusoidal Electric Field as Studied by Reflection Spectroscopy

Okubo

Ishiki

1999

Journal of Colloid and Interface Science

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Section: Electric Field Strength Dependencementioning

confidence: 97%

Section: Introductionmentioning

confidence: 96%

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Kinetic Analyses of Colloidal Crystallization in a Sinusoidal Electric Field as Studied by Reflection Spectroscopy

Okubo

Ishiki

1999

Journal of Colloid and Interface Science

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“…It should be mentioned here that the v 1 -values in the diluted suspensions decrease linearly as the reciprocal concentration of spheres increases. 41 A clear explanation for the crystallization rate first going up and then going down as sphere concentration increases has not yet been obtained. However, the main cause will be the dynamic nature of phase transition, i.e., spheres in the colloidal lattices interacting strongly with each other, and further, in a cooperative manner through the electrical double layers.…”

Section: With Spheresmentioning

confidence: 99%

“…[40][41][42][43] The number of nuclei that germinate per unit of time, the nucleation rate, v n , is given by…”

Section: With Spheresmentioning

confidence: 99%

Colloidal Crystallization As Compared with Polymer Crystallization

Okubo

2008

Polym J

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Recent work made in the author's laboratory on the morphology (especially, giant colloidal crystals), crystal structure, fundamental properties such as phase transition, light-scattering, viscosity and elasticity, crystallization kinetics and electrooptics of colloidal crystals have been reviewed. Colloidal crystals are really crystal as typical other crystals, metals, polymers and ice, for example. However, the inter-particle force of colloidal crystal is ''repulsion'' exclusively and being different from the other typical crystals, where the inter-particle ''attraction'' plays an important role for crystallization. It is pointed out that the apparent ''attraction'' is induced inevitably for the colloidal crystallization in a closed vessel.KEY WORDS: Colloidal Crystal / Colloidal Spheres / Inter-particle Electrostatic Repulsion / Crystal Structure / Light-scattering / Rigidity / Recently, keen attention has been paid for the colloidal crystals, i.e., crystal-like distribution of colloidal particles in suspensions of aqueous and organic solvents.1-13 Many researchers have studied structural colors, inter-particle interaction, crystal structure, morphology of single crystals, phase transition, crystallization kinetics of nucleation and crystal growth, physico-chemical properties (rigidity, viscosity, etc.), structural change induced by the external fields such as gravity, centrifugal and electric fields, shearing forces, and technical application (photonic crystals and electro-optic devices, etc.).Two groups of colloidal crystals have been studied hitherto: those in (i) diluted and deionized aqueous suspensions 14-26 and (ii) concentrated suspensions in the refractive index matched organic solvents. [27][28][29][30][31][32] The formers are very convenient models for both the soft and hard sphere systems, depending on the ionic concentrations of suspension, i.e., soft crystals in the exhaustively deionized state and hard crystals in the presence of rather large amount of sodium chloride, for example.Generally speaking, most colloidal particles in water get negative charges on their surfaces by two mechanisms: by the dissociation of ionizable groups and by the preferential adsorption of ions from suspension. These ionic groups leave their counter-ions, and these excess charges accumulate near the surface, forming an electrical double layer. The counterions in the diffuse region are distributed according to a balance between the thermal diffusive force and the forces of electrical attraction with colloidal particles. The importance of the electrical double layers for the colloidal crystallization has been clarified by many researchers.1-26 Giant size of single crystals has been formed in the exhaustively deionized and diluted suspension of colloidal spheres. Colloidal crystals are very beautiful and fantastic from their strong structural colors, because the inter-particle distance is just in the range of the light wavelength and each single crystal reflects light in different colors by the Bragg diffraction.In this ...

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Polymeric Colloidal Crystals

Okubo¹

2014

Encyclopedia of Polymer Science and Technology

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Recent advances in the study on the structural, dynamic and functional properties of polymeric colloidal crystals, mainly in the deionized aqueous suspension, are reviewed. Several important findings are paid attention: (a) Soft‐type colloidal crystallization takes place by the interparticle repulsion originated from the extended electrical double layers. The interaction is opposite to the importance of the interparticle attraction for crystallization of other general crystals, metals, proteins, and ice, for example. (b) Main lattice structures are face‐centered‐cubic ( fcc ) and body‐centered‐cubic ( bcc ) lattices. Packing efficiency, that is, minimizing the free volume is important. (c) Giant‐sized single crystals from the homogeneous and heterogeneous nucleation mechanisms form at the deionized and very diluted aqueous suspensions of monodisperse colloidal spheres. (d) Classical theory of crystallization holds for colloidal crystallization. (e) Viscosity, elasticity, and viscoelasticity of colloidal crystals are reviewed. (f) External field effects (gravitational, electrical, centrifugal forces, and so on) are discussed. (g) Colloidal crystal structure, morphology, and kinetics are quite similar to those of general crystals. (h) The application of colloidal crystals is also reviewed briefly.

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Kinetic Analyses of the Colloidal Crystallization of Silica Spheres As Studied by Reflection Spectroscopy

Cited by 22 publications

References 32 publications

Kinetic Analyses of Colloidal Crystallization in a Sinusoidal Electric Field as Studied by Reflection Spectroscopy

Kinetic Analyses of Colloidal Crystallization in a Sinusoidal Electric Field as Studied by Reflection Spectroscopy

Colloidal Crystallization As Compared with Polymer Crystallization

Polymeric Colloidal Crystals

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