1
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Blazquez S, Algaba J, Míguez JM, Vega C, Blas FJ, Conde MM. Three-phase equilibria of hydrates from computer simulation. I. Finite-size effects in the methane hydrate. J Chem Phys 2024; 160:164721. [PMID: 38686998 DOI: 10.1063/5.0201295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/01/2024] [Indexed: 05/02/2024] Open
Abstract
Clathrate hydrates are vital in energy research and environmental applications. Understanding their stability is crucial for harnessing their potential. In this work, we employ direct coexistence simulations to study finite-size effects in the determination of the three-phase equilibrium temperature (T3) for methane hydrates. Two popular water models, TIP4P/Ice and TIP4P/2005, are employed, exploring various system sizes by varying the number of molecules in the hydrate, liquid, and gas phases. The results reveal that finite-size effects play a crucial role in determining T3. The study includes nine configurations with varying system sizes, demonstrating that smaller systems, particularly those leading to stoichiometric conditions and bubble formation, may yield inaccurate T3 values. The emergence of methane bubbles within the liquid phase, observed in smaller configurations, significantly influences the behavior of the system and can lead to erroneous temperature estimations. Our findings reveal finite-size effects on the calculation of T3 by direct coexistence simulations and clarify the system size convergence for both models, shedding light on discrepancies found in the literature. The results contribute to a deeper understanding of the phase equilibrium of gas hydrates and offer valuable information for future research in this field.
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Affiliation(s)
- S Blazquez
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - J Algaba
- Laboratorio de Simulación Molecular y Química Computacional, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Ciencias Integradas, Universidad de Huelva, 21006 Huelva, Spain
| | - J M Míguez
- Laboratorio de Simulación Molecular y Química Computacional, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Ciencias Integradas, Universidad de Huelva, 21006 Huelva, Spain
| | - C Vega
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - F J Blas
- Laboratorio de Simulación Molecular y Química Computacional, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Ciencias Integradas, Universidad de Huelva, 21006 Huelva, Spain
| | - M M Conde
- Departamento de Ingeniería Química Industrial y del Medio Ambiente, Escuela Técnica Superior de Ingenieros Industriales, Universidad Politécnica de Madrid, 28006 Madrid, Spain
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2
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Walsh MR. Comparing brute force to transition path sampling for gas hydrate nucleation with a flat interface: comments on time reversal symmetry. Phys Chem Chem Phys 2024; 26:5762-5772. [PMID: 38214888 DOI: 10.1039/d3cp05059a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Fluid to solid nucleation is often investigated with the rare event method transition path sampling (TPS). I claim that the inherent irreversibility of solid nucleation, even at stationary conditions, calls into question TPS's applicability for determining solid nucleation mechanisms, especially for pre-critical behavior. Even when applied to a phenomenon which displays time reversal asymmetry like solid nucleation, TPS is a good means of exploring phase space and giving trends in post-critical structure, and its ability to facilitate nucleation rate and free energy calculations remains outstanding. Forward-only splitting and ratcheting methods such as forward flux sampling are more attractive for understanding nucleation mechanisms as they do not require time reversal symmetry, but at low driving forces may suffer from the same limitations as brute force: they may never make it to the first ratchet. Here I briefly summarize the TPS method and gas hydrate nucleation simulation literature, focusing on topics within both to facilitate a comparison of brute force hydrate nucleation to transition path sampling of hydrate nucleation. Perhaps anecdotally, the brute force technique results in more crystalline trajectories despite having higher driving forces than TPS. I maintain this difference is because of the inherent irreversibility of hydrate nucleation, meaning its pre-critical behavior cannot accurately be determined by the melting trajectories that comprise approximately half of the configurations in TPS's path ensemble.
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3
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Liu Y, Sun J, Chen C, Li W, Qin Y, Wang Y. Molecular insights into gas hydrate formation in the presence of graphene oxide solid surfaces. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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4
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Metya AK, Molinero V. Is Ice Nucleation by Organic Crystals Nonclassical? An Assessment of the Monolayer Hypothesis of Ice Nucleation. J Am Chem Soc 2021; 143:4607-4624. [PMID: 33729789 DOI: 10.1021/jacs.0c12012] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Potent ice nucleating organic crystals display an increase in nucleation efficiency with pressure and memory effect after pressurization that set them apart from inorganic nucleants. These characteristics were proposed to arise from an ordered water monolayer at the organic-water interface. It was interpreted that ordering of the monolayer is the limiting step for ice nucleation on organic crystals, rendering their mechanism of nucleation nonclassical. Despite the importance of organics in atmospheric ice nucleation, that explanation has never been investigated. Here we elucidate the structure of interfacial water and its role in ice nucleation at ambient pressure on phloroglucinol dihydrate, the paradigmatic example of outstanding ice nucleating organic crystal, using molecular simulations. The simulations confirm the existence of an interfacial monolayer that orders on cooling and becomes fully ordered upon ice formation. The monolayer does not resemble any ice face but seamlessly connects the distinct hydrogen-bonding orders of ice and the organic surface. Although large ordered patches develop in the monolayer before ice nucleates, we find that the critical step is the formation of the ice crystallite, indicating that the mechanism is classical. We predict that the fully ordered, crystalline monolayer nucleates ice above -2 °C and could be responsible for the exceptional ice nucleation by the organic crystal at high pressures. The lifetime of the fully ordered monolayer around 0 °C, however, is too short to account for the memory effect reported in the experiments. The latter could arise from an increase in the melting temperature of ice confined by strongly ice-binding surfaces.
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Affiliation(s)
- Atanu K Metya
- Department of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - Valeria Molinero
- Department of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, United States
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5
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Naullage PM, Molinero V. Slow Propagation of Ice Binding Limits the Ice-Recrystallization Inhibition Efficiency of PVA and Other Flexible Polymers. J Am Chem Soc 2020; 142:4356-4366. [DOI: 10.1021/jacs.9b12943] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pavithra M. Naullage
- Department of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - Valeria Molinero
- Department of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, United States
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6
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Factorovich MH, Naullage PM, Molinero V. Can clathrates heterogeneously nucleate ice? J Chem Phys 2019; 151:114707. [DOI: 10.1063/1.5119823] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- Matías H. Factorovich
- Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, USA
| | - Pavithra M. Naullage
- Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, USA
| | - Valeria Molinero
- Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, USA
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7
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Crystal Growth in Gels from the Mechanisms of Crystal Growth to Control of Polymorphism: New Trends on Theoretical and Experimental Aspects. CRYSTALS 2019. [DOI: 10.3390/cryst9090443] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A gel can be considered to be a two-phase (liquid and solid) system, which lacks flow once it reaches a stationary state. The solid phase is usually a tridimensional polymeric mesh, while the liquid phase is usually found in three forms: contained in great cavities, retained in the capillary pores between micelles, or adsorbed on the surface of a micelle. The influence of the use of gels in crystal growth is diverse and depends on the type of gel being used. A decrease in solubility of any solute in the liquid may occur if the solvent interacts extensively with the polymeric section, hence, the nucleation in gels in these cases apparently occurs at relatively low supersaturations. However, if the pore size is small enough, there is a possibility that a higher supersaturation is needed, due to the compartmentalization of solvents. Finally, this may also represent an effect in the diffusion of substances. This review is divided into three main parts; the first evaluates the theory and practice used for the obtainment of polymorphs. The second part describes the use of gels into crystallogenesis of different substances. The last part is related to the particularities of protein crystal polymorphism, as well as modern trends in gel growth for high-resolution X-ray crystallography.
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8
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Leoni F, Shi R, Tanaka H, Russo J. Crystalline clusters in mW water: Stability, growth, and grain boundaries. J Chem Phys 2019; 151:044505. [DOI: 10.1063/1.5100812] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Fabio Leoni
- School of Mathematics, University of Bristol, Bristol BS8 1TW, United Kingdom
| | - Rui Shi
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Hajime Tanaka
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - John Russo
- School of Mathematics, University of Bristol, Bristol BS8 1TW, United Kingdom
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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9
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Marriott M, Lupi L, Kumar A, Molinero V. Following the nucleation pathway from disordered liquid to gyroid mesophase. J Chem Phys 2019; 150:164902. [PMID: 31042878 DOI: 10.1063/1.5081850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mesophases have order intermediate between liquids and crystals and arise in systems with frustration, such as surfactants, block copolymers, and Janus nanoparticles. The gyroid mesophase contains two interpenetrated, nonintersecting chiral networks that give it properties useful for photonics. It is challenging to nucleate a gyroid from the liquid. Elucidating the reaction coordinate for gyroid nucleation could assist in designing additives that facilitate the formation of the mesophase. However, the complexity of the gyroid structure and the extreme weakness of the first-order liquid to gyroid transition make this a challenging quest. Here, we investigate the pathway and transition states for the nucleation of a gyroid from the liquid in molecular simulations with a mesogenic binary mixture. We find that the gyroid nuclei at the transition states have a large degree of positional disorder and are not compact, consistent with the low surface free energy of the liquid-gyroid interface. A combination of bond-order parameters for the minor component is best to describe the passage from liquid to gyroid, among those we consider. The committor analyses, however, show that this best coordinate is not perfect and suggests that accounting for the relative ordering of the two interpenetrated networks in infant nuclei, as well as for signatures of ordering in the major component of the mesophase, would improve the accuracy of the reaction coordinate for gyroid formation and its use to evaluate nucleation barriers. To our knowledge, this study is the first to investigate the reaction coordinate and critical nuclei for the formation of any mesophase from an amorphous phase.
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Affiliation(s)
- Maile Marriott
- Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-085, USA
| | - Laura Lupi
- Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-085, USA
| | - Abhinaw Kumar
- Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-085, USA
| | - Valeria Molinero
- Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-085, USA
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10
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Naullage P, Bertolazzo AA, Molinero V. How Do Surfactants Control the Agglomeration of Clathrate Hydrates? ACS CENTRAL SCIENCE 2019; 5:428-439. [PMID: 30937370 PMCID: PMC6439454 DOI: 10.1021/acscentsci.8b00755] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Indexed: 05/14/2023]
Abstract
Clathrate hydrates can spontaneously form under typical conditions found in oil and gas pipelines. The agglomeration of clathrates into large solid masses plugs the pipelines, posing adverse safety, economic, and environmental threats. Surfactants are customarily used to prevent the aggregation of clathrate particles and their coalescence with water droplets. It is generally assumed that a large contact angle between the surfactant-covered clathrate and water is a key predictor of the antiagglomerant performance of the surfactant. Here we use molecular dynamic simulations to investigate the structure and dynamics of surfactant films at the clathrate-oil interface, and their impact on the contact angle and coalescence between water droplets and hydrate particles. In agreement with the experiments, the simulations predict that surfactant-covered clathrate-oil interfaces are oil wet but super-hydrophobic to water. Although the water contact angle determines the driving force for coalescence, we find that a large contact angle is not sufficient to predict good antiagglomerant performance of a surfactant. We conclude that the length of the surfactant molecules, the density of the interfacial film, and the strength of binding of its molecules to the clathrate surface are the main factors in preventing the coalescence and agglomeration of clathrate particles with water droplets in oil. Our analysis provides a molecular foundation to guide the molecular design of effective clathrate antiagglomerants.
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Affiliation(s)
- Pavithra
M. Naullage
- Department
of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - Andressa A. Bertolazzo
- Department
of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, United States
- Departamento
de Ciências Exatas e Educação, Universidade Federal de Santa Catarina, Blumenau, Santa Catarina, Brazil
| | - Valeria Molinero
- Department
of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, United States
- E-mail:
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11
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Kumar A, Nguyen AH, Okumu R, Shepherd TD, Molinero V. Could Mesophases Play a Role in the Nucleation and Polymorph Selection of Zeolites? J Am Chem Soc 2018; 140:16071-16086. [DOI: 10.1021/jacs.8b06664] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Abhinaw Kumar
- Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
| | - Andrew H. Nguyen
- Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
| | - Rita Okumu
- Department of Chemistry, Westminster College, 1840 South 1300 East, Salt Lake City, Utah 84105, United States
| | - Tricia D. Shepherd
- Department of Chemistry, Westminster College, 1840 South 1300 East, Salt Lake City, Utah 84105, United States
| | - Valeria Molinero
- Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
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12
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Looijmans SFP, Cavallo D, Yu L, Peters GWM. Cross-Nucleation between Polymorphs: Quantitative Modeling of Kinetics and Morphology. CRYSTAL GROWTH & DESIGN 2018; 18:3921-3926. [PMID: 29991931 PMCID: PMC6034164 DOI: 10.1021/acs.cgd.8b00254] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/08/2018] [Indexed: 06/08/2023]
Abstract
Cross-nucleation is defined as the nucleation of one polymorph on the surface of another polymorph of the same substance. Although the description of this particular form of heterogeneous nucleation is mainly phenomenological, recently dedicated quantitative studies are performed on several systems. In this work we propose a model framework that captures the phenomenon of cross-nucleation for a spherulitic seed-surface geometry, as well as the kinetic competition between the seed growth and the cross-nucleus formation, by the introduction of a tangential growth rate of the daughter polymorph. Regardless of the growth rate of the parent spherulite, this model describes the experimental data up to and including the final amount of cross-nuclei on its periphery, solely based on one parameter, the cross-nucleation rate. Furthermore, a strong temperature dependency of the kinetic competition between concomitantly growing α- and β-phase isotactic polypropylene is observed and related to the previously reported anomalous behavior of this cross-nucleating system.
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Affiliation(s)
- Stan F.
S. P. Looijmans
- Department
of Mechanical Engineering, Eindhoven University
of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Dario Cavallo
- Department
of Chemistry and Industrial Chemistry, University
of Genova, Via Dodecaneso,
31, 16146 Genova, Italy
| | - Lian Yu
- School
of Pharmacy and Department of Chemistry, University of Wisconsin-Madison, 777 Highland Avenue, Madison, Wisconsin 53705, United States
| | - Gerrit W. M. Peters
- Department
of Mechanical Engineering, Eindhoven University
of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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13
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Bertolazzo AA, Naullage PM, Peters B, Molinero V. The Clathrate-Water Interface Is Oleophilic. J Phys Chem Lett 2018; 9:3224-3231. [PMID: 29812945 DOI: 10.1021/acs.jpclett.8b01210] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The slow nucleation of clathrate hydrates is a central challenge for their use in the storage and transportation of natural gas. Molecules that strongly adsorb to the clathrate-water interface decrease the crystal-water surface tension, lowering the barrier for clathrate nucleation. Surfactants are widely used to promote the nucleation and growth of clathrate hydrates. It has been proposed that these amphiphilic molecules bind to the clathrate surface via hydrogen bonding. However, recent studies reveal that PVCap, an amphiphilic polymer, binds to clathrates through hydrophobic moieties. Here we use molecular dynamic simulations and theory to investigate the mode and strength of binding of surfactants to the clathrate-water interface and their effect on the nucleation rate. We find that the surfactants bind to the clathrate-water interface exclusively through their hydrophobic tails. The binding is strong, driven by the entropy of dehydration of the alkyl chain, as it penetrates empty cavities at the hydrate surface. The hydrophobic attraction of alkyl groups to the clathrate surface also results in strong adsorption of alkanes. We identify two regimes for the binding of surfactants as a function of their density at the hydrate surface, which we interpret to correspond to the two steps of the Langmuir adsorption isotherm observed in experiments. Our results indicate that hydrophobic attraction to the clathrate-water interface is key for the design of soluble additives that promote the nucleation of hydrates. We use the calculated adsorption coefficients to estimate the concentration of sodium dodecyl sulfate (SDS) required to reach nucleation rates for methane hydrate consistent with those measured in experiments. To our knowledge, this study is the first to quantify the effect of surfactant concentration in the nucleation rate of clathrate hydrates.
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Affiliation(s)
- Andressa A Bertolazzo
- Department of Chemistry , The University of Utah , Salt Lake City , Utah 84112-0580 , United States
- Departamento de Ciências Exatas e Educação , Universidade Federal de Santa Catarina , Blumenau , State of Santa Catarina 88040-900 , Brazil
| | - Pavithra M Naullage
- Department of Chemistry , The University of Utah , Salt Lake City , Utah 84112-0580 , United States
| | - Baron Peters
- Department of Chemical Engineering , University of California , Santa Barbara , California 93106 , United States
| | - Valeria Molinero
- Department of Chemistry , The University of Utah , Salt Lake City , Utah 84112-0580 , United States
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14
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Kumar A, Molinero V. Why Is Gyroid More Difficult to Nucleate from Disordered Liquids than Lamellar and Hexagonal Mesophases? J Phys Chem B 2018; 122:4758-4770. [PMID: 29620902 DOI: 10.1021/acs.jpcb.8b02381] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Block copolymers, surfactants, and biomolecules form lamellar, hexagonal, and gyroid mesophases. Across these systems, the nucleation of lamellar from the disordered liquid is the easiest and the nucleation of gyroid the most challenging. This poses the question of what are the factors that determine the rates of nucleation of the mesophases and whether they are controlled by the complexity of the structures or the thermodynamics of nucleation. Here, we use molecular simulations to investigate the nucleation and thermodynamics of lamellar, hexagonal, and gyroid in a binary mixture of particles that produces the same mesophases as those of surfactants and block copolymers. We demonstrate that a combination of averaged bond-order parameters q̅2 and q̅8 identifies and distinguishes the three mesophases. We use these parameters to track the microscopic process of nucleation of each mesophase and investigate the existence of heterogeneous nucleation (cross-nucleation) between mesophases. We estimate the surface tensions of the liquid/mesophase interfaces from nucleation rates using classical nucleation theory and find that they are comparable for the three mesophases with values that are about a third of those expected for liquid-crystal interfaces. The driving forces for nucleation, on the other hand, are quite different and increase in the order gyroid < hexagonal < lamellar at any temperature. We find that the nucleation rates of the mesophases follow the order of their driving forces. We conclude that the difficulty to nucleate the gyroid originates in its lower temperature of melting and extremely low entropy of melting compared to those of the hexagonal and lamellar mesophases.
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Affiliation(s)
- Abhinaw Kumar
- Department of Chemistry , The University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112-0850 , United States
| | - Valeria Molinero
- Department of Chemistry , The University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112-0850 , United States
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15
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Ranieri U, Koza MM, Kuhs WF, Klotz S, Falenty A, Gillet P, Bove LE. Fast methane diffusion at the interface of two clathrate structures. Nat Commun 2017; 8:1076. [PMID: 29057864 PMCID: PMC5715113 DOI: 10.1038/s41467-017-01167-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 08/23/2017] [Indexed: 11/30/2022] Open
Abstract
Methane hydrates naturally form on Earth and in the interiors of some icy bodies of the Universe, and are also expected to play a paramount role in future energy and environmental technologies. Here we report experimental observation of an extremely fast methane diffusion at the interface of the two most common clathrate hydrate structures, namely clathrate structures I and II. Methane translational diffusion—measured by quasielastic neutron scattering at 0.8 GPa—is faster than that expected in pure supercritical methane at comparable pressure and temperature. This phenomenon could be an effect of strong confinement or of methane aggregation in the form of micro-nanobubbles at the interface of the two structures. Our results could have implications for understanding the replacement kinetics during sI–sII conversion in gas exchange experiments and for establishing the methane mobility in methane hydrates embedded in the cryosphere of large icy bodies in the Universe. Methane dynamics at the interface of ice clathrate structures is expected to play a role in phenomena ranging from gas exchange to methane mobility in planetary cryospheres. Here, the authors observe extremely fast methane diffusion at the interface of the two most common clathrate hydrate structures.
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Affiliation(s)
- Umbertoluca Ranieri
- EPSL, ICMP, École polytechnique fédérale de Lausanne (EPFL), Station 3, CH-1015, Lausanne, Switzerland. .,Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042, Grenoble cedex 9, France.
| | - Michael Marek Koza
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042, Grenoble cedex 9, France
| | - Werner F Kuhs
- GZG Abt. Kristallographie, Universität Göttingen, Goldschmidtstrasse 1, 37077, Göttingen, Germany
| | - Stefan Klotz
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Université Pierre et Marie Curie Paris 06, CNRS Unité Mixte de Recherche 7590, Sorbonne Universités, F-75252, Paris, France
| | - Andrzej Falenty
- GZG Abt. Kristallographie, Universität Göttingen, Goldschmidtstrasse 1, 37077, Göttingen, Germany
| | - Philippe Gillet
- EPSL, ICMP, École polytechnique fédérale de Lausanne (EPFL), Station 3, CH-1015, Lausanne, Switzerland
| | - Livia E Bove
- EPSL, ICMP, École polytechnique fédérale de Lausanne (EPFL), Station 3, CH-1015, Lausanne, Switzerland. .,Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Université Pierre et Marie Curie Paris 06, CNRS Unité Mixte de Recherche 7590, Sorbonne Universités, F-75252, Paris, France.
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16
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Amos DM, Donnelly ME, Teeratchanan P, Bull CL, Falenty A, Kuhs WF, Hermann A, Loveday JS. A Chiral Gas-Hydrate Structure Common to the Carbon Dioxide-Water and Hydrogen-Water Systems. J Phys Chem Lett 2017; 8:4295-4299. [PMID: 28820945 DOI: 10.1021/acs.jpclett.7b01787] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present full in situ structural solutions of carbon dioxide hydrate-II and hydrogen hydrate C0 at elevated pressures using neutron and X-ray diffraction. We find both hydrates adopt a common water network structure. The structure exhibits several features not previously found in hydrates; most notably it is chiral and has large open spiral channels along which the guest molecules are free to move. It has a network that is unrelated to any experimentally known ice, silica, or zeolite network but is instead related to two Zintl compounds. Both hydrates are found to be stable in electronic structure calculations, with hydration ratios in very good agreement with experiment.
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Affiliation(s)
- Daniel M Amos
- SUPA, School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh , Edinburgh EH9 3JZ, United Kingdom
| | - Mary-Ellen Donnelly
- SUPA, School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh , Edinburgh EH9 3JZ, United Kingdom
| | - Pattanasak Teeratchanan
- SUPA, School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh , Edinburgh EH9 3JZ, United Kingdom
| | - Craig L Bull
- ISIS Facility, STFC Rutherford Appleton Laboratory , Chilton, Oxon, OX11 0QX, United Kingdom
| | - Andrzej Falenty
- GZG Abteilung Kristallographie, Universität Göttingen , Goldschmidtstrasse 1, 37077 Göttingen, Germany
| | - Werner F Kuhs
- GZG Abteilung Kristallographie, Universität Göttingen , Goldschmidtstrasse 1, 37077 Göttingen, Germany
| | - Andreas Hermann
- SUPA, School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh , Edinburgh EH9 3JZ, United Kingdom
| | - John S Loveday
- SUPA, School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh , Edinburgh EH9 3JZ, United Kingdom
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17
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Song B, Charest N, Alexander Morriss-Andrews H, Molinero V, Shea JE. Systematic derivation of implicit solvent models for the study of polymer collapse. J Comput Chem 2017; 38:1353-1361. [DOI: 10.1002/jcc.24754] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 01/08/2017] [Accepted: 01/10/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Bin Song
- Department of Chemistry; The University of Utah; Salt Lake City Utah 84112-0850
| | - Nathaniel Charest
- Department of Chemistry and Biochemistry; University of California; Santa Barbara California 93106
| | - Herbert Alexander Morriss-Andrews
- Department of Chemistry and Biochemistry; University of California; Santa Barbara California 93106
- Department of Physics; University of California; Santa Barbara California 93106
| | - Valeria Molinero
- Department of Chemistry; The University of Utah; Salt Lake City Utah 84112-0850
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry; University of California; Santa Barbara California 93106
- Department of Physics; University of California; Santa Barbara California 93106
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18
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Lu J, Chakravarty C, Molinero V. Relationship between the line of density anomaly and the lines of melting, crystallization, cavitation, and liquid spinodal in coarse-grained water models. J Chem Phys 2016; 144:234507. [DOI: 10.1063/1.4953854] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jibao Lu
- Department of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, USA
| | | | - Valeria Molinero
- Department of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, USA
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19
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Zhang Z, Liu CJ, Walsh MR, Guo GJ. Effects of ensembles on methane hydrate nucleation kinetics. Phys Chem Chem Phys 2016; 18:15602-8. [PMID: 27222203 DOI: 10.1039/c6cp02171a] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
By performing molecular dynamics simulations to form a hydrate with a methane nano-bubble in liquid water at 250 K and 50 MPa, we report how different ensembles, such as the NPT, NVT, and NVE ensembles, affect the nucleation kinetics of the methane hydrate. The nucleation trajectories are monitored using the face-saturated incomplete cage analysis (FSICA) and the mutually coordinated guest (MCG) order parameter (OP). The nucleation rate and the critical nucleus are obtained using the mean first-passage time (MFPT) method based on the FS cages and the MCG-1 OPs, respectively. The fitting results of MFPT show that hydrate nucleation and growth are coupled together, consistent with the cage adsorption hypothesis which emphasizes that the cage adsorption of methane is a mechanism for both hydrate nucleation and growth. For the three different ensembles, the hydrate nucleation rate is quantitatively ordered as follows: NPT > NVT > NVE, while the sequence of hydrate crystallinity is exactly reversed. However, the largest size of the critical nucleus appears in the NVT ensemble, rather than in the NVE ensemble. These results are helpful for choosing a suitable ensemble when to study hydrate formation via computer simulations, and emphasize the importance of the order degree of the critical nucleus.
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Affiliation(s)
- Zhengcai Zhang
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
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20
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Hudait A, Qiu S, Lupi L, Molinero V. Free energy contributions and structural characterization of stacking disordered ices. Phys Chem Chem Phys 2016; 18:9544-53. [PMID: 26983558 DOI: 10.1039/c6cp00915h] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Crystallization of ice from deeply supercooled water and amorphous ices - a process of fundamental importance in the atmosphere, interstellar space, and cryobiology - results in stacking disordered ices with a wide range of metastabilities with respect to hexagonal ice. The structural origin of this high variability, however, has not yet been elucidated. Here we use molecular dynamics simulations with the mW water model to characterize the structure of ice freshly grown from supercooled water at temperatures from 210 to 270 K, the thermodynamics of stacking faults, line defects, and interfaces, and to elucidate the interplay between kinetics and thermodynamics in determining the structure of ice. In agreement with experiments, the ice grown in the simulations is stacking disordered with a random distribution of cubic and hexagonal layers, and a cubicity that decreases with growth temperature. The former implies that the cubicity of ice is determined by processes at the ice/liquid interface, without memory of the structure of buried ice layers. The latter indicates that the probability of building a cubic layer at the interface decreases upon approaching the melting point of ice, which we attribute to a more efficient structural equilibration of ice at the liquid interface as the driving force for growth wanes. The free energy cost for creating a pair of cubic layers in ice is 8.0 J mol(-1) in experiments, and 9.7 ± 1.9 J mol(-1) for the mW water model. This not only validates the simulations, but also indicates that dispersion in cubicity is not sufficient to explain the large energetic variability of stacking disordered ices. We compute the free energy cost of stacking disorder, line defects, and interfaces in ice and conclude that a characterization of the density of these defects is required to predict the degree of metastability and vapor pressure of atmospheric ices.
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Affiliation(s)
- Arpa Hudait
- Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, USA.
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21
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Cavallo D, Zhang L, Sics I, Alfonso GC, Dumas P, Marco C, Ellis G. The morphology and polymorphism of self-nucleated trigonal isotactic poly(1-butene) studied by synchrotron IR microspectroscopy. CrystEngComm 2016. [DOI: 10.1039/c5ce01727k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Mechanical instability of monocrystalline and polycrystalline methane hydrates. Nat Commun 2015; 6:8743. [PMID: 26522051 PMCID: PMC4659946 DOI: 10.1038/ncomms9743] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 09/28/2015] [Indexed: 01/08/2023] Open
Abstract
Despite observations of massive methane release and geohazards associated with gas hydrate instability in nature, as well as ductile flow accompanying hydrate dissociation in artificial polycrystalline methane hydrates in the laboratory, the destabilising mechanisms of gas hydrates under deformation and their grain-boundary structures have not yet been elucidated at the molecular level. Here we report direct molecular dynamics simulations of the material instability of monocrystalline and polycrystalline methane hydrates under mechanical loading. The results show dislocation-free brittle failure in monocrystalline hydrates and an unexpected crossover from strengthening to weakening in polycrystals. Upon uniaxial depressurisation, strain-induced hydrate dissociation accompanied by grain-boundary decohesion and sliding destabilises the polycrystals. In contrast, upon compression, appreciable solid-state structural transformation dominates the response. These findings provide molecular insight not only into the metastable structures of grain boundaries, but also into unusual ductile flow with hydrate dissociation as observed during macroscopic compression experiments. Sediment-hosted gas hydrates may release vast quantities of methane upon failure, but destabilizing mechanisms at the molecular level are poorly understood. Here, the authors study the deformation using simulations and find that failure differs between single crystals and polycrystalline hydrates.
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23
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Liang S, Kusalik PG. Communication: Structural interconversions between principal clathrate hydrate structures. J Chem Phys 2015; 143:011102. [DOI: 10.1063/1.4923465] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Shuai Liang
- Key Laboratory of Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, China
| | - Peter G. Kusalik
- Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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24
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Mithen JP, Callison AJ, Sear RP. Nucleation of crystals that are mixed composites of all three polymorphs in the Gaussian core model. J Chem Phys 2015; 142:224505. [DOI: 10.1063/1.4922321] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- J. P. Mithen
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - A. J. Callison
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - R. P. Sear
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
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25
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Malkin TL, Murray BJ, Salzmann CG, Molinero V, Pickering SJ, Whale TF. Stacking disorder in ice I. Phys Chem Chem Phys 2015; 17:60-76. [PMID: 25380218 DOI: 10.1039/c4cp02893g] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Traditionally, ice I was considered to exist in two well-defined crystalline forms at ambient pressure: stable hexagonal ice (ice Ih) and metastable cubic ice (ice Ic). However, it is becoming increasingly evident that what has been called cubic ice in the past does not have a structure consistent with the cubic crystal system. Instead, it is a stacking-disordered material containing cubic sequences interlaced with hexagonal sequences, which is termed stacking-disordered ice (ice Isd). In this article, we summarise previous work on ice with stacking disorder including ice that was called cubic ice in the past. We also present new experimental data which shows that ice which crystallises after heterogeneous nucleation in water droplets containing solid inclusions also contains stacking disorder even at freezing temperatures of around -15 °C. This supports the results from molecular simulations, that the structure of ice that crystallises initially from supercooled water is always stacking-disordered and that this metastable ice can transform to the stable hexagonal phase subject to the kinetics of recrystallization. We also show that stacking disorder in ice which forms from water droplets is quantitatively distinct from ice made via other routes. The emerging picture of ice I is that of a very complex material which frequently contains stacking disorder and this stacking disorder can vary in complexity depending on the route of formation and thermal history.
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Affiliation(s)
- Tamsin L Malkin
- Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
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26
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Concomitant Crystallization and Cross-Nucleation in Polymorphic Polymers. POLYMER CRYSTALLIZATION II 2015. [DOI: 10.1007/12_2015_330] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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27
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Identification of Clathrate Hydrates, Hexagonal Ice, Cubic Ice, and Liquid Water in Simulations: the CHILL+ Algorithm. J Phys Chem B 2014; 119:9369-76. [DOI: 10.1021/jp510289t] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Mochizuki K, Himoto K, Matsumoto M. Diversity of transition pathways in the course of crystallization into ice VII. Phys Chem Chem Phys 2014; 16:16419-25. [DOI: 10.1039/c4cp01616e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new metastable ice phase is discovered in the freezing pathway into ice VII in accord with Ostwald's step rule.
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Affiliation(s)
- Kenji Mochizuki
- Department of Chemistry
- Okayama University
- Okayama 700-8530, Japan
| | - Kazuhiro Himoto
- Department of Chemistry
- Okayama University
- Okayama 700-8530, Japan
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