Nonclassical Nucleation and Crystallization

Cölfen, Helmut

doi:10.3390/cryst10020061

Cited by 17 publications

(19 citation statements)

References 19 publications

(18 reference statements)

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“…Although there were a few studies that focused on the spatiotemporal analysis of pattern formation, they overlooked the formation process of the single band, which is the basic unit of the pattern. ,, (3) Pattern formation has been considered a result of simple precipitation, ,,, which omits the complicated process where constituent precipitates are actually developed by the aggregation of primary particles larger than atoms/ions/molecules. Recently, an increasing number of discoveries have indicated that crystallization proceeds through the attachment of amorphous intermediate precursors. − …”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal and Microscopic Analyses of Asymmetric Liesegang Bands: Diffusion-Limited Crystallization of Calcium Phosphate in a Hydrogel

Cho

Holló

et al. 2021

Crystal Growth & Design

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In the more than 100 years since the Liesegang phenomenon was discovered, intensive studies have been conducted to understand and control the characteristics of the periodic precipitation patterns in which the outer electrolyte diffuses into a hydrogel containing the inner electrolyte. Between fields of physics and chemistry, the periodicity of the precipitate has been investigated restrictively by spatial analyses and numerical simulations at macroscopic scales and it has been considered as a result of simple precipitation. In this work, calcium ion diffusion into gelatin hydrogels containing phosphate ions, a biomimetic system for bone formation, resulted in typical Liesegang patterns at macroscopic scales, but the asymmetric growth of the crystal was found in every single band at microscopic scales, which has not been observed or overlooked in the previous reports. The pattern consists of three characteristic bands: a continuous band, a split-fin band, and an intact-fin band. While the continuous band has a uniform crystal density, the split-fin and intact-fin bands have asymmetric crystal densities along the single band. We investigate the formation process of individual bands as well as the whole pattern by combining microscopic and spatiotemporal analyses based on the nucleation theory. Formation processes of asymmetric bands are explained by the unique stability and the diffusive property of amorphous precursors depending on the rate of calcium ion delivery. This is the first study to focus on the inhomogeneity of a single band in Liesegang patterns and the time-dependent mechanism of its growth.

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Section: Introductionmentioning

confidence: 99%

Spatiotemporal and Microscopic Analyses of Asymmetric Liesegang Bands: Diffusion-Limited Crystallization of Calcium Phosphate in a Hydrogel

Cho

Holló

et al. 2021

Crystal Growth & Design

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“…Adding water to the reaction mixture gives rise to COF-5 crystals with larger diameters by shifting the equilibrium from large oligomers towards monomers, thereby favoring lateral (pathway 1) over vertical growth (pathway 2). The crystallization of COF-5 is non-classical and similar to crystallization by particle attachment (CPA), [38][39][40] since oligomers are the key precursors in the nucleation process and dominate vertical growth. On the other hand, as opposed to the CPA mechanism, COF-5 crystallization involves several metastable species like oligomers and stacked structures in the nucleation process, different mechanisms in vertical and lateral growth, and simultaneous presence of the classical monomer-by-monomer addition mechanism that dominates the lateral growth of the COF-5 crystals.…”

Section: Figmentioning

confidence: 99%

Boronic-acid-derived covalent organic frameworks: from synthesis to applications

et al. 2021

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“…Crystallization by particle attachment (CPA), a so called non‐classical crystallization mechanism, is known to form morphological and textural patterns that cannot be explained in the scope of classical nucleation and growth models. [ 8 ] This is not surprising as CPA is a multi‐step process where every step has its own intricate interplay between thermodynamic and kinetic constrains defining a very unique crystal growth pathway. As an example, crystallization by amorphous particle attachment involves the formation and stabilization of amorphous particles, their accretion and, finally, transformation into the crystalline phase.…”

Section: Introductionmentioning

confidence: 99%

Crystallization by Amorphous Particle Attachment: On the Evolution of Texture

et al. 2021

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Crystallization by particle attachment (CPA) is a gradual process where each step has its own thermodynamic and kinetic constrains defining a unique pathway of crystal growth. An important example is biomineralization of calcium carbonate through amorphous precursors that are morphed into shapes and textural patterns that cannot be envisioned by the classical monomer‐by‐monomer approach. Here, a mechanistic link between the collective kinetics of mineral deposition and the emergence of crystallographic texture is established. Using the prismatic ultrastructure in bivalve shells as a model, a fundamental leap is made in the ability to analytically describe the evolution of form and texture of biological mineralized tissues and to design the structure and crystallographic properties of synthetic materials formed by CPA.

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Nonclassical Nucleation and Crystallization

Abstract: Nucleation and growth are of uttermost importance for crystallization since they determine the structure, shape, and properties of a crystal [...]

Cited by 17 publications

References 19 publications

Spatiotemporal and Microscopic Analyses of Asymmetric Liesegang Bands: Diffusion-Limited Crystallization of Calcium Phosphate in a Hydrogel

Spatiotemporal and Microscopic Analyses of Asymmetric Liesegang Bands: Diffusion-Limited Crystallization of Calcium Phosphate in a Hydrogel

Boronic-acid-derived covalent organic frameworks: from synthesis to applications

Crystallization by Amorphous Particle Attachment: On the Evolution of Texture

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