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Ogrin P, Urbic T. Rose water in random porous media: Associative replica Ornstein-Zernike theory study. J Mol Liq 2022; 368:120682. [PMID: 37731589 PMCID: PMC10508880 DOI: 10.1016/j.molliq.2022.120682] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The properties of water are vastly affected by its local environment or in other words the system in which water is present. There are many systems in which water is confined in pores of different sizes and shapes. We studied the system in which porous media consisted of quenched Lennard-Jones disks and water modelled as rose water which was allowed to move inside pores. Associative replica Ornstein-Zernike theory was used to calculate the properties of the system. The accuracy of the theory under different conditions was tested against Monte Carlo simulations. The advantage of the theory is that it is magnitudes faster than computer simulations. From pair distribution functions calculated with the theory, the effects of different conditions on the structure of the system was investigated. We also studied how different conditions such as fluid temperature, fluid density, matrix density and matrix particle size affect a fraction of bonded molecules, excess internal energy and isothermal compressibility.
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Affiliation(s)
- Peter Ogrin
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Vecna Pot 113, SI-1000 Ljubljana, Slovenia
| | - Tomaz Urbic
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Vecna Pot 113, SI-1000 Ljubljana, Slovenia
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2
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Stadik A, Kahl G. Deformable hard particles confined in a disordered porous matrix. J Chem Phys 2021; 155:244507. [PMID: 34972368 DOI: 10.1063/5.0068680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
With suitably designed Monte Carlo simulations, we have investigated the properties of mobile, impenetrable, yet deformable particles that are immersed into a porous matrix, the latter one realized by a frozen configuration of spherical particles. By virtue of a model put forward by Batista and Miller [Phys. Rev. Lett. 105, 088305 (2010)], the fluid particles can change in their surroundings, formed by other fluid particles or the matrix particles, their shape within the class of ellipsoids of revolution; such a change in shape is related to a change in energy, which is fed into suitably defined selection rules in the deformation "moves" of the Monte Carlo simulations. This concept represents a simple yet powerful model of realistic, deformable molecules with complex internal structures (such as dendrimers or polymers). For the evaluation of the properties of the system, we have used the well-known quenched-annealed protocol (with its characteristic double average prescription) and have analyzed the simulation data in terms of static properties (the radial distribution function and aspect ratio distribution of the ellipsoids) and dynamic features (notably the mean squared displacement). Our data provide evidence that the degree of deformability of the fluid particles has a distinct impact on the aforementioned properties of the system.
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Affiliation(s)
- Alexander Stadik
- Institute for Theoretical Physics and Center for Computational Materials Science (CMS), Technische Universität Wien, Wiedner Hauptstraße 8-10, A-1040 Wien, Austria
| | - Gerhard Kahl
- Institute for Theoretical Physics and Center for Computational Materials Science (CMS), Technische Universität Wien, Wiedner Hauptstraße 8-10, A-1040 Wien, Austria
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Qiao CZ, Zhao SL, Liu HL, Dong W. Connect the Thermodynamics of Bulk and Confined Fluids: Confinement-Adsorption Scaling. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:3840-3847. [PMID: 30691262 DOI: 10.1021/acs.langmuir.8b03126] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A fluid (a gas or a liquid) adsorbed in a porous material can behave very differently from its bulk counterpart. The advent of various synthesized materials with nanopores and their wide applications have provided strong impetus for studying fluids in confinement because our current understanding is still incomplete. From a large number of Monte Carlo simulations, we found a scaling relation that allows for connecting some thermodynamic properties (chemical potential, free energy per particle, and grand potential per particle) of a confined fluid to the bulk ones. Upon rescaling the adsorbed fluid density, the adsorption isotherms for many different confining environments collapse to the corresponding bulk curve. We also reveal the intimate connection of the reported scaling relation to Gibbs theory of inhomogeneous fluids and morphological thermodynamics. The advance in our understanding of confined fluids, gained from this study, also opens attractive perspectives for circumventing experimental difficulty for directly measuring some fluid thermodynamic properties in nanoporous materials.
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Affiliation(s)
- C Z Qiao
- Université de Lyon, CNRS, Ecole Normale Supérieure de Lyon, Université Lyon 1, Laboratoire de Chimie, UMR 5182 , 46, Allée d'Italie , 69364 Lyon Cedex 07 , France
| | | | | | - W Dong
- Université de Lyon, CNRS, Ecole Normale Supérieure de Lyon, Université Lyon 1, Laboratoire de Chimie, UMR 5182 , 46, Allée d'Italie , 69364 Lyon Cedex 07 , France
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Abstract
Colloidal diffusion in confined geometries is analysed at the level of anisotropic pair densities.
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Affiliation(s)
- Kim Nygård
- Department of Chemistry and Molecular Biology
- University of Gothenburg
- SE-41296 Gothenburg
- Sweden
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5
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Lomba E, Bores C, Notario R, Sánchez-Gil V. An integral equation and simulation study of hydrogen inclusions in a molecular crystal of short-capped nanotubes. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:344006. [PMID: 27367179 DOI: 10.1088/0953-8984/28/34/344006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this work we have assessed the ability of a recently proposed three-dimensional integral equation approach to describe the explicit spatial distribution of molecular hydrogen confined in a crystal formed by short-capped nanotubes of C50 H10. To that aim we have resorted to extensive molecular simulation calculations whose results have been compared with our three-dimensional integral equation approximation. We have first tested the ability of a single C50 H10 nanocage for the encapsulation of H2 by means of molecular dynamics simulations, in particular using targeted molecular dynamics to estimate the binding Gibbs energy of a host hydrogen molecule inside the nanocage. Then, we have investigated the adsorption isotherm of the nanocage crystal using grand canonical Monte Carlo simulations in order to evaluate the maximum load of molecular hydrogen. For a packing close to the maximum load explicit hydrogen density maps and density profiles have been determined using molecular dynamics simulations and the three-dimensional Ornstein-Zernike equation with a hypernetted chain closure. In these conditions of extremely tight confinement the theoretical approach has shown to be able to reproduce the three-dimensional structure of the adsorbed fluid with accuracy down to the finest details.
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Affiliation(s)
- Enrique Lomba
- Instituto de Química Física Rocasolano, CSIC, Calle Serrano 119, E-28026 Madrid, Spain
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Lomba E, Bores C, Sánchez-Gil V, Noya EG. A three dimensional integral equation approach for fluids under confinement: Argon in zeolites. J Chem Phys 2015; 143:164703. [PMID: 26520539 DOI: 10.1063/1.4934230] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, we explore the ability of an inhomogeneous integral equation approach to provide a full three dimensional description of simple fluids under conditions of confinement in porous media. Explicitly, we will consider the case of argon adsorbed into silicalite-1, silicalite-2, and an all-silica analogue of faujasite, with a porous structure composed of linear (and zig-zag in the case of silicalite-1) channels of 5-8 Å diameter. The equation is based on the three dimensional Ornstein-Zernike approximation proposed by Beglov and Roux [J. Chem. Phys. 103, 360 (1995)] in combination with the use of an approximate fluid-fluid direct correlation function furnished by the replica Ornstein-Zernike equation with a hypernetted chain closure. Comparison with the results of grand canonical Monte Carlo/molecular dynamics simulations evidences that the theory provides an accurate description for the three dimensional density distribution of the adsorbed fluid, both at the level of density profiles and bidimensional density maps across representative sections of the porous material. In the case of very tight confinement (silicalite-1 and silicalite-2), solutions at low temperatures could not be found due to convergence difficulties, but for faujasite, which presents substantially larger channels, temperatures as low as 77 K are accessible to the integral equation. The overall results indicate that the theoretical approximation can be an excellent tool to characterize the microscopic adsorption behavior of porous materials.
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Affiliation(s)
- Enrique Lomba
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, E-28006 Madrid, Spain
| | - Cecilia Bores
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, E-28006 Madrid, Spain
| | - Vicente Sánchez-Gil
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, E-28006 Madrid, Spain
| | - Eva G Noya
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, E-28006 Madrid, Spain
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Härtel A, Kohl M, Schmiedeberg M. Anisotropic pair correlations in binary and multicomponent hard-sphere mixtures in the vicinity of a hard wall: A combined density functional theory and simulation study. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:042310. [PMID: 26565243 DOI: 10.1103/physreve.92.042310] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Indexed: 06/05/2023]
Abstract
The fundamental measure approach to classical density functional theory has been shown to be a powerful tool to predict various thermodynamic properties of hard-sphere systems. We employ this approach to determine not only one-particle densities but also two-particle correlations in binary and six-component mixtures of hard spheres in the vicinity of a hard wall. The broken isotropy enables us to carefully test a large variety of theoretically predicted two-particle features by quantitatively comparing them to the results of Brownian dynamics simulations. Specifically, we determine and compare the one-particle density, the total correlation functions, their contact values, and the force distributions acting on a particle. For this purpose, we follow the compressibility route and theoretically calculate the direct correlation functions by taking functional derivatives. We usually observe an excellent agreement between theory and simulations, except for small deviations in cases where local crystal-like order sets in. Our results set the course for further investigations on the consistency of functionals as well as for structural analysis on, e.g., the primitive model. In addition, we demonstrate that due to the suppression of local crystallization, the predictions of six-component mixtures are better than those in bidisperse or monodisperse systems. Finally, we are confident that our results of the structural modulations induced by the wall lead to a deeper understanding of ordering in anisotropic systems in general, the onset of heterogeneous crystallization, caging effects, and glassy dynamics close to a wall, as well as structural properties in systems with confinement.
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Affiliation(s)
- Andreas Härtel
- Institut of Physics, Johannes Gutenberg-University Mainz, Staudinger Weg 9, 55128 Mainz, Germany
| | - Matthias Kohl
- Institute for Theoretical Physics II: Soft Matter, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Michael Schmiedeberg
- Institute for Theoretical Physics II: Soft Matter, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
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Bores C, Lomba E, Perera A, Almarza NG. Pattern formation in binary fluid mixtures induced by short-range competing interactions. J Chem Phys 2015; 143:084501. [PMID: 26328850 DOI: 10.1063/1.4928524] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Molecular dynamics simulations and integral equation calculations of a simple equimolar mixture of diatomic molecules and monomers interacting via attractive and repulsive short-range potentials show the existence of pattern formation (microheterogeneity), mostly due to depletion forces away from the demixing region. Effective site-site potentials extracted from the pair correlation functions using an inverse Monte Carlo approach and an integral equation inversion procedure exhibit the features characteristic of a short-range attractive and a long-range repulsive potential. When charges are incorporated into the model, this becomes a coarse grained representation of a room temperature ionic liquid, and as expected, intermediate range order becomes more pronounced and stable.
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Affiliation(s)
- Cecilia Bores
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, E-28006 Madrid, Spain
| | - Enrique Lomba
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, E-28006 Madrid, Spain
| | - Aurélien Perera
- Laboratoire de Physique Théorique de la Matiére Condensée (UMR CNRS 7600), Université Pierre et Marie Curie, 4 Place Jussieu, F75252 Paris Cedex 05, France
| | - Noé G Almarza
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, E-28006 Madrid, Spain
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Bores C, Almarza NG, Lomba E, Kahl G. Inclusions of a two dimensional fluid with competing interactions in a disordered, porous matrix. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:194127. [PMID: 25923467 DOI: 10.1088/0953-8984/27/19/194127] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The behavior of a fluid with competing interaction ranges adsorbed in a controlled pore size disordered matrix is studied by means of grand canonical Monte Carlo simulations in order to analyze the effects of confinement. The disordered matrix model is constructed from a two-dimensional non-additive hard-sphere fluid (which shows close to its demixing critical point large fluctuations in the concentration), after a subsequent quenching of the particle positions and removal of one of the components. The topology of the porous network is analyzed by means of a Delaunay tessellation procedure. The porous cavities are large enough to allow for cluster formation, which is however somewhat hindered as a result of the confinement, as seen from the comparison of cluster size distributions calculated for the fluid under confinement and in the bulk. The occurrence of lamellar phases is impeded by the disordered nature of the porous network. Analysis of two-dimensional density maps of the adsorbed fluid for given matrix configurations shows that clusters tend to build up in specific locations of the porous matrix, so as to minimize inter-cluster repulsion.
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Affiliation(s)
- Cecilia Bores
- Instituto de Química Física Rocasolano, CSIC, Calle Serrano 119, E-28026 Madrid, Spain
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