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Desgranges C, Delhommelle J. Accelerated convergence via adiabatic sampling for adsorption and desorption processes. J Chem Phys 2024; 161:104104. [PMID: 39248234 DOI: 10.1063/5.0223486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Accepted: 08/20/2024] [Indexed: 09/10/2024] Open
Abstract
Under isothermal conditions, phase transitions occur through a nucleation event when conditions are sufficiently close to coexistence. The formation of a nucleus of the new phase requires the system to overcome a free energy barrier of formation, whose height rapidly rises as supersaturation decreases. This phenomenon occurs both in the bulk and under confinement and leads to a very slow kinetics for the transition, ultimately resulting in hysteresis, where the system can remain in a metastable state for a long time. This has broad implications, for instance, when using simulations to predict phase diagrams or screen porous materials for gas storage applications. Here, we leverage simulations in an adiabatic statistical ensemble, known as adiabatic grand-isochoric ensemble (μ, V, L) ensemble, to reach equilibrium states with a greater efficiency than its isothermal counterpart, i.e., simulations in the grand-canonical ensemble. For the bulk, we show that at low supersaturation, isothermal simulations converge slowly, while adiabatic simulations exhibit a fast convergence over a wide range of supersaturation. We then focus on adsorption and desorption processes in nanoporous materials, assess the reliability of (μ, V, L) simulations on the adsorption of argon in IRMOF-1, and demonstrate the efficiency of adiabatic simulations to predict efficiently the equilibrium loading during the adsorption and desorption of argon in MCM-41, a system that exhibits significant hysteresis. We provide quantitative measures of the increased rate of convergence when using adiabatic simulations. Adiabatic simulations explore a wide temperature range, leading to a more efficient exploration of the configuration space.
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Affiliation(s)
- Caroline Desgranges
- Department of Physics and Applied Physics, University of Massachusetts, Lowell, Massachusetts 01854, USA
| | - Jerome Delhommelle
- Department of Chemistry, University of Massachusetts, Lowell, Massachusetts 01854, USA
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Prado Camargo A, Jusufi A, Lee AG, Koplik J, Morris JF, Giovambattista N. Water and Carbon Dioxide Capillary Bridges in Nanoscale Slit Pores: Effects of Temperature, Pressure, and Salt Concentration on the Water Contact Angle. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:18439-18450. [PMID: 39158401 PMCID: PMC11375785 DOI: 10.1021/acs.langmuir.4c01185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/20/2024]
Abstract
We perform molecular dynamics (MD) simulations of a nanoscale water capillary bridge (WCB) surrounded by carbon dioxide over a wide range of temperatures and pressures (T = 280-400 K and carbon dioxide pressures P CO 2 ≈ 0-80 MPa). The water-carbon dioxide system is confined by two parallel silica-based surfaces (hydroxylated β-cristobalite) separated by h = 5 nm. The aim of this work is to study the WCB contact angle (θc) as a function of T and P CO 2 . Our simulations indicate that θc varies weakly with temperature and pressure: Δθc ≈ 10-20° for P CO 2 increasing from ≈0 to 80 MPa (T = 320 K); Δθc ≈ -10° for T increasing from 320 to 360 K (with a fixed amount of carbon dioxide). Interestingly, at all conditions studied, a thin film of water (1-2 water layers-thick) forms under the carbon dioxide volume. Our MD simulations suggest that this is due to the enhanced ability of water, relative to carbon dioxide, to form hydrogen-bonds with the walls. We also study the effects of adding salt (NaCl) to the WCB and corresponding θc. It is found that at the salt concentrations studied (mole fractions xNa = xCl = 3.50, 9.81%), the NaCl forms a large crystallite within the WCB with the ions avoiding the water-carbon dioxide interface and the walls surface. This results in θc being insensitive to the presence of NaCl.
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Affiliation(s)
| | - Arben Jusufi
- ExxonMobil Technology and Engineering Company, 1545 US Rt. 22 East, Annandale, New Jersey 08801, United States
| | - Alex Gk Lee
- ExxonMobil Technology and Engineering Company, 1545 US Rt. 22 East, Annandale, New Jersey 08801, United States
| | - Joel Koplik
- Levich Institute, City College of New York, New York, New York 10031, United States
- Department of Physics, City College of New York, New York, New York 10031, United States
- Ph.D. Program in Physics, The Graduate Center of the City University of New York, New York, New York 10016, United States
| | - Jeffrey F Morris
- Levich Institute, City College of New York, New York, New York 10031, United States
- Ph.D. Program in Physics, The Graduate Center of the City University of New York, New York, New York 10016, United States
- Department of Chemical Engineering, City College of New York, New York, New York 10031, United States
| | - Nicolas Giovambattista
- Ph.D. Program in Physics, The Graduate Center of the City University of New York, New York, New York 10016, United States
- Department of Physics, Brooklyn College of the City University of New York, Brooklyn, New York 11210, United States
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Machine-Learned Free Energy Surfaces for Capillary Condensation and Evaporation in Mesopores. ENTROPY 2022; 24:e24010097. [PMID: 35052123 PMCID: PMC8774451 DOI: 10.3390/e24010097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/29/2021] [Accepted: 01/05/2022] [Indexed: 12/04/2022]
Abstract
Using molecular simulations, we study the processes of capillary condensation and capillary evaporation in model mesopores. To determine the phase transition pathway, as well as the corresponding free energy profile, we carry out enhanced sampling molecular simulations using entropy as a reaction coordinate to map the onset of order during the condensation process and of disorder during the evaporation process. The structural analysis shows the role played by intermediate states, characterized by the onset of capillary liquid bridges and bubbles. We also analyze the dependence of the free energy barrier on the pore width. Furthermore, we propose a method to build a machine learning model for the prediction of the free energy surfaces underlying capillary phase transition processes in mesopores.
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Desgranges C, Delhommelle J. The central role of entropy in adiabatic ensembles and its application to phase transitions in the grand-isobaric adiabatic ensemble. J Chem Phys 2020; 153:094114. [PMID: 32891099 DOI: 10.1063/5.0021488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Entropy has become increasingly central to characterize, understand, and even guide assembly, self-organization, and phase transition processes. In this work, we build on the analogous role of partition functions (or free energies) in isothermal ensembles and that of entropy in adiabatic ensembles. In particular, we show that the grand-isobaric adiabatic (μ, P, R) ensemble, or Ray ensemble, provides a direct route to determine the entropy. This allows us to follow the variations of entropy with the thermodynamic conditions and thus explore phase transitions. We test this approach by carrying out Monte Carlo simulations on argon and copper in bulk phases and at phase boundaries. We assess the reliability and accuracy of the method through comparisons with the results from flat-histogram simulations in isothermal ensembles and with the experimental data. Advantages of the approach are multifold and include the direct determination of the μ-P relation, without any evaluation of pressure via the virial expression, the precise control of the system size (number of atoms) via the input value of R, and the straightforward computation of enthalpy differences for isentropic processes, which are key quantities to determine the efficiency of thermodynamic cycles. A new insight brought by these simulations is the highly symmetric pattern exhibited by both systems along the transition, as shown by scaled temperature-entropy and pressure-entropy plots.
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Affiliation(s)
- Caroline Desgranges
- Department of Chemistry, New York University, New York, New York 10003, USA and Department of Chemistry, University of North Dakota, Grand Forks, North Dakota 58202, USA
| | - Jerome Delhommelle
- Department of Chemistry, New York University, New York, New York 10003, USA and Department of Chemistry, University of North Dakota, Grand Forks, North Dakota 58202, USA
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Desgranges C, Delhommelle J. Unraveling liquid polymorphism in silicon driven out-of-equilibrium. J Chem Phys 2020; 153:054502. [DOI: 10.1063/5.0015417] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Caroline Desgranges
- Department of Chemistry, New York University, New York, New York 10003, USA and Department of Chemistry, University of North Dakota, Grand Forks, North Dakota 58202, USA
| | - Jerome Delhommelle
- Department of Chemistry, New York University, New York, New York 10003, USA and Department of Chemistry, University of North Dakota, Grand Forks, North Dakota 58202, USA
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Desgranges C, Delhommelle J. Nucleation of Capillary Bridges and Bubbles in Nanoconfined CO 2. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15401-15409. [PMID: 31675236 DOI: 10.1021/acs.langmuir.9b01744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Using molecular simulation, we examine the capillary condensation and the capillary evaporation of CO2 in cylindrical nanopores. More specifically, we employ the recently developed μV T-S method to determine the microscopic mechanism associated with these processes and the corresponding free energy profiles. We calculate the free energy barrier for capillary condensation and identify that the key step consists in the nucleation of a liquid bridge of a critical size. Similarly, the free energy maximum found for the capillary evaporation process is found to correspond to the nucleation of a vapor bubble of a critical size. In addition, we assess the impact of the strength of the wall-fluid on the height of the free energy barrier and on the critical size of liquid bridges (condensation process) and vapor bubbles (evaporation process). We observe that the height of the free energy barrier increases with the strength of the wall-fluid interactions. Finally, we build a theoretical model, based on capillary theory, to rationalize our findings. In particular, the simulation results reveal a linear scaling of the free energy barrier with the critical size, in excellent agreement with the theoretical predictions.
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Affiliation(s)
- Caroline Desgranges
- Department of Chemistry , New York University , New York , New York 10003 , United States
- Department of Chemistry , University of North Dakota , Grand Forks , North Dakota 58202 , United States
| | - Jerome Delhommelle
- Department of Chemistry , New York University , New York , New York 10003 , United States
- Department of Chemistry , University of North Dakota , Grand Forks , North Dakota 58202 , United States
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Iwamatsu M, Mori H. Effect of line tension on axisymmetric nanoscale capillary bridges at the liquid-vapor equilibrium. Phys Rev E 2019; 100:042802. [PMID: 31770920 DOI: 10.1103/physreve.100.042802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Indexed: 06/10/2023]
Abstract
The effect of line tension on the axisymmetric nanoscale capillary bridge between two identical substrates with convex, concave, and flat geometry at the liquid-vapor equilibrium is theoretically studied. The modified Young's equation for the contact angle, which takes into account the effect of line tension, is derived on a general axisymmetric curved surface using the variational method. Even without the effect of line tension, the parameter space where the bridge can exist is limited simply by the geometry of substrates. The modified Young's equation further restricts the space where the bridge can exist when the line tension is positive because the equilibrium contact angle always remains finite and the wetting state near the zero contact angle cannot be realized. It is shown that the interplay of the geometry and the positive line tension restricts the formation of capillary bridge.
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Affiliation(s)
- Masao Iwamatsu
- Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - Hiroyuki Mori
- Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
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Tanaka H, Miyahara MT. Free energy calculations for adsorption-induced deformation of flexible metal–organic frameworks. Curr Opin Chem Eng 2019. [DOI: 10.1016/j.coche.2019.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Xi E, Marks SM, Fialoke S, Patel AJ. Sparse sampling of water density fluctuations near liquid-vapor coexistence. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1457218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Erte Xi
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, PA, USA
| | - Sean M. Marks
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, PA, USA
| | - Suruchi Fialoke
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, PA, USA
| | - Amish J. Patel
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, PA, USA
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Calculating free energy profiles using entropy as a reaction coordinate: Application to water nucleation. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.02.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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