1
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Condensation and Crystal Nucleation in a Lattice Gas with a Realistic Phase Diagram. ENTROPY 2022; 24:e24030419. [PMID: 35327929 PMCID: PMC8953323 DOI: 10.3390/e24030419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/15/2022] [Accepted: 03/15/2022] [Indexed: 11/17/2022]
Abstract
We reconsider model II of Orban et al. (J. Chem. Phys. 1968, 49, 1778−1783), a two-dimensional lattice-gas system featuring a crystalline phase and two distinct fluid phases (liquid and vapor). In this system, a particle prevents other particles from occupying sites up to third neighbors on the square lattice, while attracting (with decreasing strength) particles sitting at fourth- or fifth-neighbor sites. To make the model more realistic, we assume a finite repulsion at third-neighbor distance, with the result that a second crystalline phase appears at higher pressures. However, the similarity with real-world substances is only partial: Upon closer inspection, the alleged liquid−vapor transition turns out to be a continuous (albeit sharp) crossover, even near the putative triple point. Closer to the standard picture is instead the freezing transition, as we show by computing the free-energy barrier relative to crystal nucleation from the “liquid”.
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2
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Munaò G, Prestipino S, Bomont JM, Costa D. Clustering in Mixtures of SALR Particles and Hard Spheres with Cross Attraction. J Phys Chem B 2022; 126:2027-2039. [PMID: 35224968 PMCID: PMC8919255 DOI: 10.1021/acs.jpcb.1c09758] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Self-assembling complex
fluids are often modeled as particles with
effective competing isotropic interactions, combining a short-range
attraction (SA) followed by a longer-range repulsion (LR). For moderately
low temperatures and densities, SALR particles form clusters in equilibrium,
at least provided that the potential parameters are appropriate. Here
we inquire into the possibility that cluster formation in SALR fluids
might be pushed by a foreign species even under thermodynamic conditions
that would not allow for clusterization of the pure system. To this
aim, we study by Monte Carlo simulations a mixture of hard-sphere
two-Yukawa particles and hard spheres, with a cross interaction modeled
by a square-well attraction, and we investigate the conditions of
clustering in terms of strength of attraction and relative concentration
of the two species. We find that clusters can occur in the mixture
for the same temperature and density where the pure SALR fluid is
almost structureless. In particular, we single out a cross attraction
such that clusters are formed with a SALR concentration as low as
5%. We also find a situation where nearly pure droplets of hard spheres
are held together by a shell of SALR particles. Conversely, we show
that clustering can be undermined in the mixture under conditions
for which this process takes place in the parent SALR fluid. Using
a simple criterion, based on the second virial coefficients of the
attractive part of interaction potentials (the so-called “reference
attractive fluids”), we are able to predict accurately whether
clustering is favored (or hindered) in the mixture, as compared to
the pure SALR fluid.
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Affiliation(s)
- Gianmarco Munaò
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Santi Prestipino
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Jean-Marc Bomont
- Université de Lorraine, LCP-A2MC, UR 3469, 1 Blvd. François Arago, Metz F-57078, France
| | - Dino Costa
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
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3
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Maeritz M, Oettel M. Droplet condensation in the lattice gas with density functional theory. Phys Rev E 2021; 104:034127. [PMID: 34654142 DOI: 10.1103/physreve.104.034127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/16/2021] [Indexed: 06/13/2023]
Abstract
A density functional for the lattice gas with next-neighbor attractions (Ising model) from fundamental measure theory is applied to the problem of droplet states in three-dimensional, finite systems. The density functional is constructed via an auxiliary model with hard lattice gas particles and lattice polymers to incorporate the attractions. Similar to previous simulation studies, the sequence of droplets changing to cylinders and to planar slabs is found upon increasing the average density ρ[over ¯] in the system. Owing to the discreteness of the lattice, additional effects in the state curve for the chemical potential μ(ρ[over ¯]) are seen upon lowering the temperature away from the critical temperature [oscillations in μ(ρ[over ¯]) in the slab portion and spiky undulations in μ(ρ[over ¯]) in the cylinder portion as well as an undulatory behavior of the radius of the surface of tension R_{s} in the droplet region]. This behavior in the cylinder and droplet region is related to washed-out layering transitions at the surface of liquid cylinders and droplets. The analysis of the large-radius behavior of the surface tension γ(R_{s}) gave a dominant contribution ∝1/R_{s}^{2}, although the consistency of γ(R_{s}) with the asymptotic behavior of the radius-dependent Tolman length seems to suggest a weak logarithmic contribution ∝lnR_{s}/R_{s}^{2} in γ(R_{s}). The coefficient of this logarithmic term is smaller than a universal value derived with field-theoretic methods.
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Affiliation(s)
- M Maeritz
- Institut für Angewandte Physik, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany
| | - M Oettel
- Institut für Angewandte Physik, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany
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4
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Prestipino S, Sergi A, Bruno E, Giaquinta PV. A variational mean-field study of clusterization in a zero-temperature system of soft-core bosons. EPJ WEB OF CONFERENCES 2020. [DOI: 10.1051/epjconf/202023000008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We work out the ground-state diagram of weakly-repulsive penetrable bosons, using mean-field theory with a Gaussian ansatz on the single-particle wave function. Upon compression, the fluid transforms into a cluster supersolid, whose structure is characterized for various choices of the embedding space. In Euclidean space, the stable crystals are those with the most compact structure, i.e., triangular and fcc in two and three dimensions, respectively. For particles confined in a spherical surface, as the sphere radius increases we observe a sequence of transitions between different cluster phases, all having a regular or semiregular polyhedron as supporting frame for the clusters. The present results are relevant for the behavior of ultracold bosons weakly coupled to a Rydberg state.
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5
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Horsley EM, Lavrentovich MO, Kamien RD. Aspects of nucleation on curved and flat surfaces. J Chem Phys 2018; 148:234701. [PMID: 29935505 DOI: 10.1063/1.5030752] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the energetics of droplets sourced by the thermal fluctuations in a system undergoing a first-order transition. In particular, we confine our studies to two dimensions with explicit calculations in the plane and on the sphere. Using an isoperimetric inequality from the differential geometry literature and a theorem on the inequality's saturation, we show how geometry informs the critical droplet size and shape. This inequality establishes a "mean field" result for nucleated droplets. We then study the effects of fluctuations on the interfaces of droplets in two dimensions, treating the droplet interface as a fluctuating line. We emphasize that care is needed in deriving the line curvature energy from the Landau-Ginzburg energy functional and in interpreting the scalings of the nucleation rate with the size of the droplet. We end with a comparison of nucleation in the plane and on a sphere.
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Affiliation(s)
- Eric M Horsley
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Maxim O Lavrentovich
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Randall D Kamien
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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6
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Das SK, Egorov SA, Virnau P, Winter D, Binder K. Do the contact angle and line tension of surface-attached droplets depend on the radius of curvature? JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:255001. [PMID: 29741496 DOI: 10.1088/1361-648x/aac363] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Results from Monte Carlo simulations of wall-attached droplets in the three-dimensional Ising lattice gas model and in a symmetric binary Lennard-Jones fluid, confined by antisymmetric walls, are analyzed, with the aim to estimate the dependence of the contact angle [Formula: see text] on the droplet radius [Formula: see text] of curvature. Sphere-cap shape of the wall-attached droplets is assumed throughout. An approach, based purely on 'thermodynamic' observables, e.g. chemical potential, excess density due to the droplet, etc, is used, to avoid ambiguities in the decision which particles belong (or do not belong, respectively) to the droplet. It is found that the results are compatible with a variation [Formula: see text], [Formula: see text] being the contact angle in the thermodynamic limit ([Formula: see text]). The possibility to use such results to estimate the excess free energy related to the contact line of the droplet, namely the line tension, at the wall, is discussed. Various problems that hamper this approach and were not fully recognized in previous attempts to extract the line tension are identified. It is also found that the dependence of wall tensions on the difference of chemical potential of the droplet from that at the bulk coexistence provides effectively a change of the contact angle of similar magnitude. The simulation approach yields precise estimates for the excess density due to wall-attached droplets and the corresponding free energy excess, relative to a system without a droplet at the same chemical potential. It is shown that this information suffices to estimate nucleation barriers, not affected by ambiguities on droplet shape, contact angle and line tension.
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Affiliation(s)
- Subir K Das
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 56004, India
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7
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Richard D, Speck T. Crystallization of hard spheres revisited. II. Thermodynamic modeling, nucleation work, and the surface of tension. J Chem Phys 2018; 148:224102. [DOI: 10.1063/1.5025394] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- David Richard
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7-9, 55128 Mainz, Germany
| | - Thomas Speck
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7-9, 55128 Mainz, Germany
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8
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Prestipino S, Munaò G, Costa D, Pellicane G, Caccamo C. Two-dimensional mixture of amphiphilic dimers and spheres: Self-assembly behaviour. J Chem Phys 2018; 147:144902. [PMID: 29031271 DOI: 10.1063/1.4995549] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The emergence of supramolecular aggregates from simple microscopic interaction rules is a fascinating feature of complex fluids which, besides its fundamental interest, has potential applications in many areas, from biological self-assembly to smart material design. We here investigate by Monte Carlo simulation the equilibrium structure of a two-dimensional mixture of asymmetric dimers and spheres (disks). Dimers and disks are hard particles, with an additional short-range attraction between a disk and the smaller monomer of a dimer. The model parameters and thermodynamic conditions probed are typical of colloidal fluid mixtures. In spite of the minimalistic character of the interaction, we observe-upon varying the relative concentration and size of the two colloidal species-a rich inventory of mesoscale structures at low temperature, such as clusters, lamellæ (i.e., polymer-like chains), and gel-like networks. For colloidal species of similar size and near equimolar concentrations, a dilute fluid of clusters gives way to floating lamellæ upon cooling; at higher densities, the lamellæ percolate through the simulation box, giving rise to an extended network. A crystal-vapour phase-separation may occur for a mixture of dimers and much larger disks. Finally, when the fluid is brought in contact with a planar wall, further structures are obtained at the interface, from layers to branched patterns, depending on the nature of wall-particle interactions.
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Affiliation(s)
- Santi Prestipino
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra,Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Gianmarco Munaò
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra,Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Dino Costa
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra,Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Giuseppe Pellicane
- School of Chemistry and Physics, University of Kwazulu-Natal, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa
| | - Carlo Caccamo
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra,Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
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9
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Prestipino S, Munaò G, Costa D, Caccamo C. Self-assembly in a model colloidal mixture of dimers and spherical particles. J Chem Phys 2018; 146:084902. [PMID: 28249437 DOI: 10.1063/1.4976704] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We investigate the structure of a dilute mixture of amphiphilic dimers and spherical particles, a model relevant to the problem of encapsulating globular "guest" molecules in a dispersion. Dimers and spheres are taken to be hard particles, with an additional attraction between spheres and the smaller monomers in a dimer. Using the Monte Carlo simulation, we document the low-temperature formation of aggregates of guests (clusters) held together by dimers, whose typical size and shape depend on the guest concentration χ. For low χ (less than 10%), most guests are isolated and coated with a layer of dimers. As χ progressively increases, clusters grow in size becoming more and more elongated and polydisperse; after reaching a shallow maximum for χ≈50%, the size of clusters again reduces upon increasing χ further. In one case only (χ=50% and moderately low temperature) the mixture relaxed to a fluid of lamellae, suggesting that in this case clusters are metastable with respect to crystal-vapor separation. On heating, clusters shrink until eventually the system becomes homogeneous on all scales. On the other hand, as the mixture is made denser and denser at low temperature, clusters get increasingly larger until a percolating network is formed.
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Affiliation(s)
- Santi Prestipino
- Dipartimento di Scienze Matematiche ed Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Gianmarco Munaò
- Dipartimento di Scienze Matematiche ed Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Dino Costa
- Dipartimento di Scienze Matematiche ed Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Carlo Caccamo
- Dipartimento di Scienze Matematiche ed Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
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10
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Affiliation(s)
- Santi Prestipino
- Dipartimento di Scienze Matematiche ed Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
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11
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Tröster A, Schmitz F, Virnau P, Binder K. Equilibrium between a Droplet and Surrounding Vapor: A Discussion of Finite Size Effects. J Phys Chem B 2017; 122:3407-3417. [DOI: 10.1021/acs.jpcb.7b10392] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andreas Tröster
- Institute of Materials Chemistry, Vienna University of Technology, Getreidemarkt 9, A-1060 Wien, Austria
| | - Fabian Schmitz
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 9, D-55099 Mainz, Germany
| | - Peter Virnau
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 9, D-55099 Mainz, Germany
| | - Kurt Binder
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 9, D-55099 Mainz, Germany
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12
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Koß P, Statt A, Virnau P, Binder K. Free-energy barriers for crystal nucleation from fluid phases. Phys Rev E 2017; 96:042609. [PMID: 29347490 DOI: 10.1103/physreve.96.042609] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Indexed: 06/07/2023]
Abstract
Monte Carlo simulations of crystal nuclei coexisting with the fluid phase in thermal equilibrium in finite volumes are presented and analyzed, for fluid densities from dense melts to the vapor. Generalizing the lever rule for two-phase coexistence in the canonical ensemble to finite volume, "measurements" of the nucleus volume together with the pressure and chemical potential of the surrounding fluid allows us to extract the surface free energy of the nucleus. Neither the knowledge of the (in general nonspherical) nucleus shape nor of the angle-dependent interface tension is required for this task. The feasibility of the approach is demonstrated for a variant of the Asakura-Oosawa model for colloid-polymer mixtures, which form face-centered cubic colloidal crystals. For a polymer to colloid size ratio of 0.15, the colloid packing fraction in the fluid phase can be varied from melt values to zero by the variation of an effective attractive potential between the colloids. It is found that the approximation of spherical crystal nuclei often underestimates actual nucleation barriers significantly. Nucleation barriers are found to scale as ΔF^{*}=(4π/3)^{1/3}γ[over ¯](V^{*})^{2/3}+const with the nucleus volume V^{*}, and the effective surface tension γ[over ¯] that accounts implicitly for the nonspherical shape can be precisely estimated.
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Affiliation(s)
- Peter Koß
- Institut für Physik, Johannes Gutenberg-Universität, D-55128 Mainz, Staudinger Weg 9, Germany
- Graduate School Materials Science in Mainz, D-55128 Mainz, Staudinger Weg 9, Germany
| | - Antonia Statt
- Institut für Physik, Johannes Gutenberg-Universität, D-55128 Mainz, Staudinger Weg 9, Germany
- Graduate School Materials Science in Mainz, D-55128 Mainz, Staudinger Weg 9, Germany
- Department of Chemical and Biological Engineering, Princeton School of Engineering and Applied Science, Princeton, New Jersey 08544, USA
| | - Peter Virnau
- Institut für Physik, Johannes Gutenberg-Universität, D-55128 Mainz, Staudinger Weg 9, Germany
- Graduate School Materials Science in Mainz, D-55128 Mainz, Staudinger Weg 9, Germany
| | - Kurt Binder
- Institut für Physik, Johannes Gutenberg-Universität, D-55128 Mainz, Staudinger Weg 9, Germany
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13
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Burian S, Isaiev M, Termentzidis K, Sysoev V, Bulavin L. Size dependence of the surface tension of a free surface of an isotropic fluid. Phys Rev E 2017; 95:062801. [PMID: 28709294 DOI: 10.1103/physreve.95.062801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Indexed: 06/07/2023]
Abstract
We report on the size dependence of the surface tension of a free surface of an isotropic fluid. The size dependence of the surface tension is evaluated based on the Gibbs-Tolman-Koenig-Buff equation for positive and negative values of curvatures and the Tolman lengths. For all combinations of positive and negative signs of curvature and the Tolman length, we succeed to have a continuous function, avoiding the existing discontinuity at zero curvature (flat interfaces). As an example, a water droplet in the thermodynamical equilibrium with the vapor is analyzed in detail. The size dependence of the surface tension and the Tolman length are evaluated with the use of experimental data of the International Association for the Properties of Water and Steam. The evaluated Tolman length of our approach is in good agreement with molecular dynamics and experimental data.
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Affiliation(s)
- Sergii Burian
- Faculty of Physics, Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Street, Kyiv 01601, Ukraine
| | - Mykola Isaiev
- Faculty of Physics, Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Street, Kyiv 01601, Ukraine
- LEMTA-Université de Lorraine-CNRS UMR 7563, Faculté des Sciences et Technologies, Boîte Postale 70239, 54506 Vandoeuvre les Nancy cedex, France
| | - Konstantinos Termentzidis
- LEMTA-Université de Lorraine-CNRS UMR 7563, Faculté des Sciences et Technologies, Boîte Postale 70239, 54506 Vandoeuvre les Nancy cedex, France
| | - Vladimir Sysoev
- Faculty of Physics, Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Street, Kyiv 01601, Ukraine
| | - Leonid Bulavin
- Faculty of Physics, Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Street, Kyiv 01601, Ukraine
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14
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Zierenberg J, Schierz P, Janke W. Canonical free-energy barrier of particle and polymer cluster formation. Nat Commun 2017; 8:14546. [PMID: 28240262 PMCID: PMC5333364 DOI: 10.1038/ncomms14546] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 01/10/2017] [Indexed: 12/16/2022] Open
Abstract
A common approach to study nucleation rates is the estimation of free-energy barriers. This usually requires knowledge about the shape of the forming droplet, a task that becomes notoriously difficult in macromolecular setups starting with a proper definition of the cluster boundary. Here we demonstrate a shape-free determination of the free energy for temperature-driven cluster formation in particle as well as polymer systems. Combined with rigorous results on equilibrium droplet formation, this allows for a well-defined finite-size scaling analysis of the effective interfacial free energy at a fixed density. We first verify the theoretical predictions for the formation of a liquid droplet in a supersaturated particle gas by generalized-ensemble Monte Carlo simulations of a Lennard-Jones system. Going one step further, we then generalize this approach to cluster formation in a dilute polymer solution. Our results suggest an analogy with particle condensation, when the macromolecules are interpreted as extended particles.
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Affiliation(s)
- Johannes Zierenberg
- Institut für Theoretische Physik, Universität Leipzig, Postfach 100 920, D-04009 Leipzig, Germany
| | - Philipp Schierz
- Institut für Theoretische Physik, Universität Leipzig, Postfach 100 920, D-04009 Leipzig, Germany
| | - Wolfhard Janke
- Institut für Theoretische Physik, Universität Leipzig, Postfach 100 920, D-04009 Leipzig, Germany
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15
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Bomont JM, Costa D, Bretonnet JL. Tiny changes in local order identify the cluster formation threshold in model fluids with competing interactions. Phys Chem Chem Phys 2017; 19:15247-15255. [DOI: 10.1039/c7cp01811h] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In two-Yukawa fluids, the increment of attraction causes a tiny reversal of trend in the local density, within specific ranges of interparticle distances. This event precisely signals the onset of a clustered state.
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Affiliation(s)
| | - Dino Costa
- Dipartimento di Scienze Matematiche e Informatiche
- Scienze Fisiche e Scienze della Terra
- Università degli Studi di Messina
- 98158 Messina
- Italy
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16
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Jungblut S, Dellago C. Pathways to self-organization: Crystallization via nucleation and growth. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2016; 39:77. [PMID: 27498980 DOI: 10.1140/epje/i2016-16077-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 07/13/2016] [Indexed: 06/06/2023]
Abstract
Crystallization, a prototypical self-organization process during which a disordered state spontaneously transforms into a crystal characterized by a regular arrangement of its building blocks, usually proceeds by nucleation and growth. In the initial stages of the transformation, a localized nucleus of the new phase forms in the old one due to a random fluctuation. Most of these nuclei disappear after a short time, but rarely a crystalline embryo may reach a critical size after which further growth becomes thermodynamically favorable and the entire system is converted into the new phase. In this article, we will discuss several theoretical concepts and computational methods to study crystallization. More specifically, we will address the rare event problem arising in the simulation of nucleation processes and explain how to calculate nucleation rates accurately. Particular attention is directed towards discussing statistical tools to analyze crystallization trajectories and identify the transition mechanism.
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Affiliation(s)
- S Jungblut
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Wien, Austria
| | - C Dellago
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Wien, Austria.
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17
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Knežević M, Yeomans JM. Pore emptying transition during nucleation in hydrophobic nanopores. SOFT MATTER 2016; 12:3810-3819. [PMID: 26984813 DOI: 10.1039/c6sm00148c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Using the 2D Ising model we study the generic properties of nucleation in hydrophobic nanopores. To explore the pathways to nucleation of a spin-up phase from a metastable spin-down phase we perform umbrella sampling and transition path sampling simulations. We find that for narrow pores the nucleation occurs on the surface outside the pore. For wide pores the nucleation starts in the pore, and continues outside the filled pore. Intriguingly, we observe a pore emptying transition for a range of intermediate pore widths: a pre-critical nucleus fills the pore, continues to expand outside of the filled pore, but then suddenly gets expelled from the pore before reaching its critical size.
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Affiliation(s)
- Miloš Knežević
- The Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, UK.
| | - Julia M Yeomans
- The Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, UK.
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Prestipino S, Caccamo C, Costa D, Malescio G, Munaò G. Shapes of a liquid droplet in a periodic box. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:022141. [PMID: 26382377 DOI: 10.1103/physreve.92.022141] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Indexed: 06/05/2023]
Abstract
Within the coexistence region between liquid and vapor the equilibrium pressure of a simulated fluid exhibits characteristic jumps and plateaus when plotted as a function of density at constant temperature. These features exclusively pertain to a finite-size sample in a periodic box, as they are washed out in the bulk limit. Below the critical density, at each pressure jump the shape of the liquid drop undergoes a morphological transition, changing from spherical to cylindrical to slablike as the density is increased. We formulate a simple theory of these shape transitions, which is adapted from a calculation originally developed by Binder and coworkers [L. G. MacDowell, P. Virnau, M. Muller, and K. Binder, J. Chem. Phys. 120, 5293 (2004)]. Our focus is on the pressure equation of state (rather than on the chemical potential, as in the original work) and includes an extension to elongated boxes. Predictions based on this theory well agree with extensive Monte Carlo data for the cut-and-shifted Lennard-Jones fluid. We further discuss the thermodynamic stability of liquid drops with shapes other than the three mentioned above, like those found deep inside the liquid-vapor region in simulations starting from scratch. Our theory classifies these more elaborate shapes as metastable.
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Affiliation(s)
- Santi Prestipino
- Università degli Studi di Messina, Dipartimento di Fisica e di Scienze della Terra, Contrada Papardo, I-98166 Messina, Italy
- Consiglio Nazionale delle Ricerche, IPCF, Viale F. Stagno d'Alcontres 37, I-98158 Messina, Italy
| | - Carlo Caccamo
- Università degli Studi di Messina, Dipartimento di Fisica e di Scienze della Terra, Contrada Papardo, I-98166 Messina, Italy
| | - Dino Costa
- Università degli Studi di Messina, Dipartimento di Fisica e di Scienze della Terra, Contrada Papardo, I-98166 Messina, Italy
| | - Gianpietro Malescio
- Università degli Studi di Messina, Dipartimento di Fisica e di Scienze della Terra, Contrada Papardo, I-98166 Messina, Italy
| | - Gianmarco Munaò
- Università degli Studi di Messina, Dipartimento di Fisica e di Scienze della Terra, Contrada Papardo, I-98166 Messina, Italy
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Schmitz F, Virnau P. The ensemble switch method for computing interfacial tensions. J Chem Phys 2015; 142:144108. [DOI: 10.1063/1.4916317] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Fabian Schmitz
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 9, D-55128 Mainz, Germany
| | - Peter Virnau
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 9, D-55128 Mainz, Germany
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Das SK. Atomistic simulations of liquid–liquid coexistence in confinement: comparison of thermodynamics and kinetics with bulk. MOLECULAR SIMULATION 2015. [DOI: 10.1080/08927022.2014.998214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Prestipino S, Laio A, Tosatti E. Shape and area fluctuation effects on nucleation theory. J Chem Phys 2014; 140:094501. [DOI: 10.1063/1.4866971] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Prestipino S, Giaquinta PV. Spontaneous Freezing of Supercooled Water under Isochoric and Adiabatic Conditions. J Phys Chem B 2013; 117:8189-95. [DOI: 10.1021/jp403332y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Santi Prestipino
- Dipartimento di Fisica e di
Scienze della Terra, Università degli Studi di Messina, Contrada Papardo, I-98166 Messina, Italy
- CNR-IPCF, Viale F. Stagno d’Alcontres 37, I-98158 Messina, Italy
| | - Paolo V. Giaquinta
- Dipartimento di Fisica e di
Scienze della Terra, Università degli Studi di Messina, Contrada Papardo, I-98166 Messina, Italy
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Prestipino S. A maximum-entropy approach to the adiabatic freezing of a supercooled liquid. J Chem Phys 2013; 138:164501. [PMID: 23635151 DOI: 10.1063/1.4801864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
I employ the van der Waals theory of Baus and co-workers to analyze the fast, adiabatic decay of a supercooled liquid in a closed vessel with which the solidification process usually starts. By imposing a further constraint on either the system volume or pressure, I use the maximum-entropy method to quantify the fraction of liquid that is transformed into solid as a function of undercooling and of the amount of a foreign gas that could possibly be also present in the test tube. Upon looking at the implications of thermal and mechanical insulation for the energy cost of forming a solid droplet within the liquid, I identify one situation where the onset of solidification inevitably occurs near the wall in contact with the bath.
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Affiliation(s)
- Santi Prestipino
- Dipartimento di Fisica e di Scienze della Terra, Università degli Studi di Messina, Messina, Italy.
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