Phase transitions in systems small enough to be clusters

Reguera, David; Bowles, Richard K.; Djikaev, Y. S.; Reiss, Howard

doi:10.1063/1.1524192

Cited by 130 publications

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“…10,11 In particular, adopting a classical homogeneous nucleation approach for crystallization from an ideal solution in a spherical confining volume, V, the Helmholtz free energy change, ∆F, to produce a nuclei containing n molecules would be given by: 12…”

Section: Manuscript Textmentioning

confidence: 99%

Stable Polymorphs Crystallized Directly under Thermodynamic Control in Three-Dimensional Nanoconfinement: A Generic Methodology

Nicholson

Chen

Mendis

et al. 2011

Crystal Growth & Design

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. (2011) 'Stable polymorphs crystallized directly under thermodynamic control in three-dimensional nanocon nement : a generic methodology.', Crystal growth design., 11 (2). pp. 363-366. Further information on publisher's website:https://doi.org/10.1021/cg101200fPublisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Crystal growth design, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see https://doi.org/10.1021/cg101200fAdditional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThermodynamic control of crystallization has been achieved to produce stable polymorphs directly by using 3D nano-confinement in microemulsions. The theoretical basis for thermodynamic control of crystallization using 3D nano-confinement is outlined. Our approach leap-frogs the usual metastable polymorph pathway because crystallization becomes governed by the ability to form stable nuclei, rather than critical nuclei. The generality of this approach is demonstrated by crystallizing the stable polymorph of three 'problem' compounds from microemulsions under conditions yielding metastable forms in bulk solution. The polymorphic compounds are mefenamic acid (2-[(2,3-(dimethylphenyl)amino] benzoic acid), glycine (aminoethanoic acid) and the highly polymorphic 5-methyl-2-[(2-nitrophenyl) amino]-3-thiophenecarbonitrile, commonly known as ROY because of its red, orange and yellow polymorphs. Application of this methodology should prevent another Ritonavir-type disaster, whereby a marketed drug transforms into a more stable form, reducing its bioavailability and effectiveness. The lowest energy nuclei selectively grow in our approach. Consequently this also provides a generic method for producing higher crystallinity materials, which may prove beneficial for crystallizing proteins and inorganic nanocrystals.Statement of urgency and brief summary of significant findings. We believe the paper fulfills the requirements of urgency for a Communication because it details for the first time a generic method to obtain thermodynamic control of crystallization. This enables stable polymorphs to be crystallized directly, to prevent another Ritonavir-type disaster. The methodology used selectively grows the lowest energy crystal nuclei, so it can also produce materials with higher crystallinity, which may prove of use for a wide range of crystalline materials, including potential...

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Section: Manuscript Textmentioning

confidence: 99%

Stable Polymorphs Crystallized Directly under Thermodynamic Control in Three-Dimensional Nanoconfinement: A Generic Methodology

Nicholson

Chen

Mendis

et al. 2011

Crystal Growth & Design

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“…For systems containing just a few molecules, there are some additional contributions to the free energy of formation that become important. In the EMLD [9] two such contributions are incorporated. These are (i) the translation of the drop through the volume of the container [10] and (ii) the effect of fluctuations in n. (i) Since the drop does not have to appear precisely at the center of the container it can ''collide'' with the walls, thus contributing to the total pressure p n , which then consists of the sum of the gas pressure p 1 and the pressure p drop exerted by the translating drop, regarded as a single ideal hard sphere molecule.…”

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confidence: 99%

“…Most of these developments require the use of an intermolecular potential, unfortunately not reliably available for most substances. For this reason, workers have continued to rely on the classical nucleation theory (CNT) which, despite its theoretical shortcomings, requires only macroscopic thermodynamic parameters.Recently, we developed a model, the ''extended modified liquid drop'' (EMLD) model [9], that was able to reproduce with remarkable accuracy the properties of very small confined systems, without the use of an intermolecular potential. In this Letter, we present a new approach to nucleation with very useful properties, based on a combination of EMLD with DNT [6].…”

mentioning

confidence: 99%

“…Recently, we developed a model, the ''extended modified liquid drop'' (EMLD) model [9], that was able to reproduce with remarkable accuracy the properties of very small confined systems, without the use of an intermolecular potential. In this Letter, we present a new approach to nucleation with very useful properties, based on a combination of EMLD with DNT [6].…”

mentioning

confidence: 99%

“…Under these assumptions, the free energy of formation F n of the drop containing n molecules, at a fixed position within the container, can be evaluated by thermodynamic means alone, yielding [9] …”

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Fusion of the Extended Modified Liquid Drop Model for Nucleation and Dynamical Nucleation Theory

Reguera¹,

Reiss²

2004

Phys. Rev. Lett.

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We present a new phenomenological approach to nucleation, based on the combination of the ''extended modified liquid drop'' model and dynamical nucleation theory. The new model proposes a new cluster definition, which properly includes the effect of fluctuations, and it is consistent both thermodynamically and kinetically. The model is able to predict successfully the free energy of formation of the critical nucleus, using only macroscopic thermodynamic properties. It also accounts for the spinodal and provides excellent agreement with the result of recent simulations. DOI: 10.1103/PhysRevLett.93.165701 PACS numbers: 64.60.Qb, 82.20.Db, 82.60.Nh During the last decade, there have been significant advances in the theory of nucleation. These have included the use of the i; v cluster [1], the Fisher droplet model [2,3], the application of density functional theory (DFT) [4], scaling relations [5], the introduction of dynamical nucleation theory (DNT) [6], and many impressive simulations [7,8]. Most of these developments require the use of an intermolecular potential, unfortunately not reliably available for most substances. For this reason, workers have continued to rely on the classical nucleation theory (CNT) which, despite its theoretical shortcomings, requires only macroscopic thermodynamic parameters.Recently, we developed a model, the ''extended modified liquid drop'' (EMLD) model [9], that was able to reproduce with remarkable accuracy the properties of very small confined systems, without the use of an intermolecular potential. In this Letter, we present a new approach to nucleation with very useful properties, based on a combination of EMLD with DNT [6]. The new model does not require information concerning intermolecular potentials but, instead, using the same macroscopic parameters as CNT, is able to predict the spinodal. Moreover, it provides very good agreement with recent simulations of nucleation in Lennard-Jones systems [7] and fulfills scaling relations recently proposed in the literature [5].EMLD focuses on the behavior of a very small ''canonical'' system of N molecules confined to a spherical volume V of radius R, at temperature T. Under appropriate conditions, a liquid drop can form inside V. The drop itself, modeled according to the ''capillarity approximation,'' is assumed to contain n molecules and to be surrounded by an ideal gas, constituted by the remaining N ÿ n molecules. Under these assumptions, the free energy of formation F n of the drop containing n molecules, at a fixed position within the container, can be evaluated by thermodynamic means alone, yielding [9]

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Crystallization in Confinement

2020

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Many crystallization processes of great importance, including frost heave, biomineralization, the synthesis of nanomaterials, and scale formation, occur in small volumes rather than bulk solution. Here, the influence of confinement on crystallization processes is described, drawing together information from fields as diverse as bioinspired mineralization, templating, pharmaceuticals, colloidal crystallization, and geochemistry. Experiments are principally conducted within confining systems that offer well‐defined environments, varying from droplets in microfluidic devices, to cylindrical pores in filtration membranes, to nanoporous glasses and carbon nanotubes. Dramatic effects are observed, including a stabilization of metastable polymorphs, a depression of freezing points, and the formation of crystals with preferred orientations, modified morphologies, and even structures not seen in bulk. Confinement is also shown to influence crystallization processes over length scales ranging from the atomic to hundreds of micrometers, and to originate from a wide range of mechanisms. The development of an enhanced understanding of the influence of confinement on crystal nucleation and growth will not only provide superior insight into crystallization processes in many real‐world environments, but will also enable this phenomenon to be used to control crystallization in applications including nanomaterial synthesis, heavy metal remediation, and the prevention of weathering.

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Phase transitions in systems small enough to be clusters

Cited by 130 publications

References 40 publications

Stable Polymorphs Crystallized Directly under Thermodynamic Control in Three-Dimensional Nanoconfinement: A Generic Methodology

Stable Polymorphs Crystallized Directly under Thermodynamic Control in Three-Dimensional Nanoconfinement: A Generic Methodology

Fusion of the Extended Modified Liquid Drop Model for Nucleation and Dynamical Nucleation Theory

Crystallization in Confinement

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