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Voigtländer A, Houssais M, Bacik KA, Bourg IC, Burton JC, Daniels KE, Datta SS, Del Gado E, Deshpande NS, Devauchelle O, Ferdowsi B, Glade R, Goehring L, Hewitt IJ, Jerolmack D, Juanes R, Kudrolli A, Lai CY, Li W, Masteller C, Nissanka K, Rubin AM, Stone HA, Suckale J, Vriend NM, Wettlaufer JS, Yang JQ. Soft matter physics of the ground beneath our feet. SOFT MATTER 2024. [PMID: 39012310 DOI: 10.1039/d4sm00391h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
The soft part of the Earth's surface - the ground beneath our feet - constitutes the basis for life and natural resources, yet a general physical understanding of the ground is still lacking. In this critical time of climate change, cross-pollination of scientific approaches is urgently needed to better understand the behavior of our planet's surface. The major topics in current research in this area cross different disciplines, spanning geosciences, and various aspects of engineering, material sciences, physics, chemistry, and biology. Among these, soft matter physics has emerged as a fundamental nexus connecting and underpinning many research questions. This perspective article is a multi-voice effort to bring together different views and approaches, questions and insights, from researchers that work in this emerging area, the soft matter physics of the ground beneath our feet. In particular, we identify four major challenges concerned with the dynamics in and of the ground: (I) modeling from the grain scale, (II) near-criticality, (III) bridging scales, and (IV) life. For each challenge, we present a selection of topics by individual authors, providing specific context, recent advances, and open questions. Through this, we seek to provide an overview of the opportunities for the broad Soft Matter community to contribute to the fundamental understanding of the physics of the ground, strive towards a common language, and encourage new collaborations across the broad spectrum of scientists interested in the matter of the Earth's surface.
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Affiliation(s)
- Anne Voigtländer
- German Research Centre for Geosciences (GFZ), Geomorphology, Telegrafenberg, 14473 Potsdam, Germany.
- Lawrence Berkeley National Laboratory (LBNL), Energy Geosciences Division, 1 Cyclotron Rd, Berkeley, CA 94720, USA
| | - Morgane Houssais
- Department of Physics, Clark University, 950 Main St, Worcester, MA 01610, USA
| | - Karol A Bacik
- Department of Mathematics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Ian C Bourg
- Civil and Environmental Engineering (CEE) and High Meadows Environmental Institute (HMEI), Princeton University, E208 EQuad, Princeton, NJ 08540, USA
| | - Justin C Burton
- Department of Physics, Emory University, 400 Dowman Dr, Atlanta, GA 30033, USA
| | - Karen E Daniels
- North Carolina State University, 2401 Stinson Dr, Raleigh, NC 27607, USA
| | - Sujit S Datta
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Emanuela Del Gado
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC, USA
| | - Nakul S Deshpande
- North Carolina State University, 2401 Stinson Dr, Raleigh, NC 27607, USA
| | - Olivier Devauchelle
- Institut de Physique du Globe de Paris, Université Paris Cité, 1 rue Jussieu, CNRS, F-75005 Paris, France
| | - Behrooz Ferdowsi
- Department of Civil and Environmental Engineering, jUniversity of Houston, Houston, TX 77204, USA
| | - Rachel Glade
- Earth & Environmental Sciences Department and Mechanical Engineering Department, University of Rochester, 227 Hutchison Hall, P.O. Box 270221, Rochester, NY 14627, USA
| | - Lucas Goehring
- School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, UK
| | - Ian J Hewitt
- Mathematical Institute, University of Oxford, Woodstock Road, Oxford OX2 6GG, UK
| | - Douglas Jerolmack
- Department of Earth & Environmental Science, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ruben Juanes
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Arshad Kudrolli
- Department of Physics, Clark University, 950 Main St, Worcester, MA 01610, USA
| | - Ching-Yao Lai
- Department of Geophysics, Stanford University, Stanford, CA 94305, USA
| | - Wei Li
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Stony Brook University, Department of Civil Engineering, Stony Brook, NY 11794, USA
| | - Claire Masteller
- Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, USA
| | - Kavinda Nissanka
- Department of Physics, Emory University, 400 Dowman Dr, Atlanta, GA 30033, USA
| | - Allan M Rubin
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Jenny Suckale
- Computational and Mathematical Engineering, and Environmental Engineering, Stanford University, Stanford, CA 94305, USA
| | - Nathalie M Vriend
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - John S Wettlaufer
- Departments of Earth & Planetary Sciences, Mathematics and Physics, Yale University, New Haven, CT 06520, USA
- Nordic Institute for Theoretical Physics, 106 91, Stockholm, Sweden
| | - Judy Q Yang
- Saint Anthony Falls Laboratory and Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, MN, USA
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Otu DAB, Owusu FWA, Boakye-Gyasi ME, Johnson R, Acquah PGJ, Edzor-Agbo Y, Bayor MT, Archer MA. Biogenic Waste from Two Varieties of Plantain in Ghana Contain Pectin with Potential Binding Properties in Conventional Tablets. ScientificWorldJournal 2024; 2024:5461358. [PMID: 38915814 PMCID: PMC11196187 DOI: 10.1155/2024/5461358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/09/2024] [Accepted: 05/24/2024] [Indexed: 06/26/2024] Open
Abstract
Pharmaceutical formulations have traditionally relied on plants and their derivatives for various APIs and excipients. In Ghana, the widespread utilization of plantains, irrespective of their ripeness, generates significant waste at every stage of processing, posing disposal issues. Fascinatingly, these wastes, often discarded, possess significant economic potential and can be recycled into valuable raw materials or products. Pectin, a polysaccharide that occurs naturally, has seen a surge in interest in recent times. It has found widespread use in the pharmaceutical sector, particularly as a binding agent in tablet formulations. This study aimed to evaluate pectin from two popular plantain varieties, Apem (M) and Apantu (T) at different ripening stages, for pharmaceutical use as a binding agent in immediate-release tablets. The ripening stages selected were the matured-green (G), half-ripe (H), and full-ripe (R). Acid (D) and alkaline (L) mediums of extraction were employed for each ripening stage for both varieties. Wet granulation method was used to prepare the granules using paracetamol as a model drug, and their flow properties were subsequently assessed. Postcompression tests including, hardness, friability, weight uniformity, disintegration, assay, and in vitro dissolution were also assessed. Granules from all formulation batches had good flow properties indicated by their angle of repose (14.93 ± 1.41-21.80 ± 1.41), Hausner ratio (0.96 ± 0.27-1.22 ± 0.02), and compressibility (%) (7.69 ± 0.002-20.51 ± 0.002). All the tablets passed the uniformity of weight with none deviating by ±5%. The hardness of all the formulated tablets ranged between 3.96 ± 0.32 and 13.21 ± 0.36, while the friability for all tablets was below 1%. The drug content was between 100.1 ± 0.23% and 103.4 ± 0.01%. Tablets formulated with pectin as a binding agent at concentrations of 10% w/v and 15% w/v successfully met the disintegration test criteria for immediate release tablets. However, those prepared with a concentration of 20% w/v (MGL, MHD, MHL, MRD, MRL, TGL, THD, THL, and TRL) did not pass the disintegration test. Consequently, all batches of tablets successfully met the dissolution test requirement (Diss, Q > 75%), except for the batches that did not pass the disintegration test (Diss, Q < 75%). Ultimately, pectins extracted from the peels of Apem and Apantu at different ripening stages using acid and alkaline extraction can be commercially exploited as pharmaceutical binders at varying concentrations in immediate-release tablets.
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Affiliation(s)
- Desmond Asamoah Bruce Otu
- Department of Pharmaceutics, Faculty of Pharmacy and Pharmaceutical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Frederick William Akuffo Owusu
- Department of Pharmaceutics, Faculty of Pharmacy and Pharmaceutical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Mariam El Boakye-Gyasi
- Department of Pharmaceutics, Faculty of Pharmacy and Pharmaceutical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Raphael Johnson
- Department of Pharmaceutics, Faculty of Pharmacy and Pharmaceutical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Prince George Jnr Acquah
- Department of Pharmaceutics, Faculty of Pharmacy and Pharmaceutical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Yayra Edzor-Agbo
- Department of Pharmaceutics, Faculty of Pharmacy and Pharmaceutical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Marcel Tunkumgnen Bayor
- Department of Pharmaceutics, Faculty of Pharmacy and Pharmaceutical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Mary-Ann Archer
- Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences, University of Cape Coast, Cape Coast, Ghana
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Petersen T. Toward Modeling the Structure of Electrolytes at Charged Mineral Interfaces Using Classical Density Functional Theory. J Phys Chem B 2024; 128:3981-3996. [PMID: 38626457 PMCID: PMC11056995 DOI: 10.1021/acs.jpcb.3c08045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 04/18/2024]
Abstract
The organization of water molecules and ions between charged mineral surfaces determines the stability of colloidal suspensions and the strength of phase-separated particulate gels. In this article, we assemble a density functional that measures the free energy due to the interaction of water molecules and ions in electric double layers. The model accounts for the finite size of the particles using fundamental measure theory, hydrogen-bonding between water molecules using Wertheim's statistical association theory, long-range dispersion interactions using Barker and Henderson's high-temperature expansion, electrostatic correlations using a functionalized mean-spherical approximation, and Coulomb forces through the Poisson equation. These contributions are shown to produce highly correlated structures, aptly rendering the layering of counterions and co-ions at highly charged surfaces and permitting the solvation of ions and surfaces to be measured by a combination of short-range associations and long-ranged attractions. The model is tested in a planar geometry near soft, charged surfaces to reproduce the structure of water near graphene and mica. For mica surfaces, explicitly representing the density of the outer oxygen layer of the exposed silica tetrahedra allows water molecules to hydrogen-bond to the solid. When electrostatic interactions are included, water molecules assume a hybrid character, being accounted for implicitly in the dielectric constant but explicitly otherwise. The disjoining pressure between approaching like-charged surfaces is calculated, demonstrating the model's ability to probe pressure oscillations that arise during the expulsion of ions and water layers from the interfacial gap and predict strong interattractive stresses that form at narrow interfacial spacing when the surface charge is overscreened. This interattractive stress arises not due to in-plane correlations under strong electrostatic coupling but due to the out-of-plane structuring of associating ions and water molecules.
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Affiliation(s)
- Thomas Petersen
- Sonny Astani Department of
Civil and Environmental Engineering, University
of Southern California, Los Angeles, California 90089, United States
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Ghazanfari S, Alesadi A, Liao Y, Zhang Y, Xia W. Molecular insights into the temperature and pressure dependence of mechanical behavior and dynamics of Na-montmorillonite clay. NANOSCALE ADVANCES 2023; 5:5449-5459. [PMID: 37822914 PMCID: PMC10563839 DOI: 10.1039/d3na00365e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 07/18/2023] [Indexed: 10/13/2023]
Abstract
Sodium montmorillonite (Na-MMT) clay mineral is a common type of swelling clay that has potential applications for nuclear waste storage at high temperatures and pressures. However, there is a limited understanding of the mechanical properties, local molecular stiffness, and dynamic heterogeneity of this material at elevated temperatures and pressures. To address this, we employ all-atomistic (AA) molecular dynamics (MD) simulation to investigate the tensile behavior of Na-MMT clay over a wide temperature range (500 K to 1700 K) and pressures (200 atm to 100 000 atm). The results show that increasing the temperature significantly reduces the tensile modulus, strength, and failure strain, while pressure has a minor effect compared to temperature, as seen in the normalized pressure-temperature plot. Mean-square displacement (MSD) analysis reveals increased molecular stiffness with increasing pressure and decreasing temperature, indicating suppressed atomic mobility. Our simulations indicate temperature-dependent dynamical heterogeneity in the Na-MMT model, supported by experimental studies and quantified local molecular stiffness distribution. These findings enhance our understanding of the tensile response and dynamical heterogeneity of Na-MMT clay under extreme conditions, aiding the development of clay minerals for engineering applications such as nuclear waste storage and shale gas extraction.
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Affiliation(s)
- Sarah Ghazanfari
- Department of Civil, Construction and Environmental Engineering, North Dakota State University Fargo ND 58108 USA
| | - Amirhadi Alesadi
- Department of Civil, Construction and Environmental Engineering, North Dakota State University Fargo ND 58108 USA
| | - Yangchao Liao
- Department of Civil, Construction and Environmental Engineering, North Dakota State University Fargo ND 58108 USA
| | - Yida Zhang
- Department of Civil, Environmental, Architectural Engineering, University of Colorado Boulder Boulder CO 80309 USA
| | - Wenjie Xia
- Department of Civil, Construction and Environmental Engineering, North Dakota State University Fargo ND 58108 USA
- Department of Aerospace Engineering, Iowa State University Ames IA 50011 USA
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5
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Shen X, Bourg IC. Interaction between Hydrated Smectite Clay Particles as a Function of Salinity (0-1 M) and Counterion Type (Na, K, Ca). THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:20990-20997. [PMID: 37881773 PMCID: PMC10595998 DOI: 10.1021/acs.jpcc.2c04636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 11/11/2022] [Indexed: 10/27/2023]
Abstract
Swelling clay minerals control the hydrologic and mechanical properties of many soils, sediments, and sedimentary rocks. This important and well-known phenomenon remains challenging to predict because it emerges from complex multiscale couplings between aqueous chemistry and colloidal interaction mechanics in nanoporous clay assemblages, for which predictive models remain elusive. In particular, the predominant theory of colloidal interactions across fluid films, the widely used Derjaguin-Landau-Verwey-Overbeek model, fails to predict the ubiquitous existence of stable swelling states at interparticle distances below 3 nm that are stabilized by specific inter-atomic interactions in overlapping electrical double layers between the charged clay surfaces. Atomistic simulations have the potential to generate detailed insights into the mechanisms of these interactions. Recently, we developed a metadynamics-based molecular dynamics simulation methodology that can predict the free energy of interaction between parallel smectite clay particles in a wide range of interparticle distances (from 0.3 to 3 nm) and salinities (from 0.0 to 1.0 M NaCl). Here, we extend this work by characterizing the sensitivity of interparticle interactions to counterion type (Na, K, Ca). We establish a detailed picture of the free energy of interaction of parallel clay particles across water films as the sum of five interaction mechanisms with different sensitivities to salinity, counterion type, and interparticle distance.
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Affiliation(s)
- Xinyi Shen
- Department of Civil and Environmental
Engineering and High Meadows Environmental Institute, Princeton University, Princeton, New Jersey08544, United States
| | - Ian C. Bourg
- Department of Civil and Environmental
Engineering and High Meadows Environmental Institute, Princeton University, Princeton, New Jersey08544, United States
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Liberto T, Nenning A, Bellotto M, Dalconi MC, Dworschak D, Kalchgruber L, Robisson A, Valtiner M, Dziadkowiec J. Detecting Early-Stage Cohesion Due to Calcium Silicate Hydration with Rheology and Surface Force Apparatus. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:14988-15000. [PMID: 36426749 PMCID: PMC9730907 DOI: 10.1021/acs.langmuir.2c02783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/13/2022] [Indexed: 06/16/2023]
Abstract
Extremely robust cohesion triggered by calcium silicate hydrate (C-S-H) precipitation during cement hardening makes concrete one of the most commonly used man-made materials. Here, in this proof-of-concept study, we seek an additional nanoscale understanding of early-stage cohesive forces acting between hydrating model tricalcium silicate (C3S) surfaces by combining rheological and surface force measurements. We first used time-resolved small oscillatory rheology measurements (SAOSs) to characterize the early-stage evolution of the cohesive properties of a C3S paste and a C-S-H gel. SAOS revealed the reactive and viscoelastic nature of C3S pastes, in contrast with the nonreactive but still viscoelastic nature of the C-S-H gel, which proves a temporal variation in the cohesion during microstructural physicochemical rearrangements in the C3S paste. We further prepared thin films of C3S by plasma laser deposition (PLD) and demonstrated that these films are suitable for force measurements in the surface force apparatus (SFA). We measured surface forces acting between two thin C3S films exposed to water and subsequent in situ calcium silicate hydrate precipitation. With the SFA and SFA-coupled interferometric measurements, we resolved that C3S surface reprecipitation in water was associated with both increasing film thickness and progressively stronger adhesion (pull-off force). The lasting adhesion developing between the growing surfaces depended on the applied load, pull-off rate, and time in contact. These properties indicated the viscoelastic character of the soft, gel-like reprecipitated layer, pointing to the formation of C-S-H. Our findings confirm the strong cohesive properties of hydrated calcium silicate surfaces that, based on our preliminary SFA measurements, are attributed to sharp changes in the surface microstructure. In contact with water, the brittle and rough C3S surfaces with little contact area weather into soft, gel-like C-S-H nanoparticles with a much larger surface area available for forming direct contacts between interacting surfaces.
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Affiliation(s)
- Teresa Liberto
- Institute
of Materials Technology, Building Physics and Construction Ecology,
Faculty of Civil Engineering, Vienna University
of Technology, 1040 Vienna, Austria
| | - Andreas Nenning
- Institute
of Chemical Technologies and Analytics, Vienna Institute of Technology, 1060 Wien, Austria
| | | | - Maria Chiara Dalconi
- Department
of Geoscience and CIRCe Center, University
of Padua, 35131 Padova, Italy
| | - Dominik Dworschak
- Institute
of Applied Physics, Vienna Institute of
Technology, 1040 Wien, Austria
| | - Lukas Kalchgruber
- Institute
of Applied Physics, Vienna Institute of
Technology, 1040 Wien, Austria
| | - Agathe Robisson
- Institute
of Materials Technology, Building Physics and Construction Ecology,
Faculty of Civil Engineering, Vienna University
of Technology, 1040 Vienna, Austria
| | - Markus Valtiner
- Institute
of Applied Physics, Vienna Institute of
Technology, 1040 Wien, Austria
| | - Joanna Dziadkowiec
- Institute
of Applied Physics, Vienna Institute of
Technology, 1040 Wien, Austria
- NJORD Centre,
Department of Physics, University of Oslo, P.O. Box 1048, Oslo 0316, Norway
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Zhao W, Xu WW, Jiang J, Zhao X, Duan X, Sun Y, Francisco JS, Zeng XC. Evidence of Formation of Monolayer Hydrated Salts in Nanopores. J Am Chem Soc 2022; 144:18976-18985. [PMID: 36197785 DOI: 10.1021/jacs.2c07372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Despite much effort being devoted to the study of ionic aqueous solutions at the nanoscale, our fundamental understanding of the microscopic kinetic and thermodynamic behaviors in these systems remains largely incomplete. Herein, we reported the first 10 μs molecular dynamics simulation, providing evidence of the spontaneous formation of monolayer hexagonal honeycomb hydrated salts of XCl2·6H2O (X = Ba, Sr, Ca, and Mg) from electrolyte aqueous solutions confined in an angstrom-scale slit under ambient conditions. By using both the classical molecular dynamics simulations and the first-principles Born-Oppenheimer molecular dynamics simulations, we further demonstrated that the hydrated salts were stable not only at ambient temperature but also at elevated temperatures. This phenomenon of formation of hydrated salt in water is contrary to the conventional view. The free energy calculations and dehydration analyses indicated that the spontaneous formation of hydrated salts can be attributed to the interplay between ion hydration and Coulombic attractions in the highly confined water. In addition to providing molecular-level insights into the novel behavior of ionic aqueous solutions at the nanoscale, our findings may have implications for the future exploration of potential existence of water molecules in the saline deposits on hot planets.
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Affiliation(s)
- Wenhui Zhao
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Wen Wu Xu
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Jian Jiang
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States.,Department of Materials Science & Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Xiaorong Zhao
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Xiangmei Duan
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Yunxiang Sun
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Joseph S Francisco
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Xiao Cheng Zeng
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States.,Department of Materials Science & Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China
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8
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Dragulet F, Goyal A, Ioannidou K, Pellenq RJM, Del Gado E. Ion Specificity of Confined Ion-Water Structuring and Nanoscale Surface Forces in Clays. J Phys Chem B 2022; 126:4977-4989. [PMID: 35731697 DOI: 10.1021/acs.jpcb.2c01738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ion specificity and related Hofmeister effects, which are ubiquitous in aqueous systems, can have spectacular consequences in hydrated clays, where ion-specific nanoscale surface forces can determine large-scale cohesive swelling and shrinkage behaviors of soil and sediments. We have used a semiatomistic computational approach and examined sodium, calcium, and aluminum counterions confined with water between charged surfaces representative of clay materials to show that ion-water structuring in nanoscale confinement is at the origin of surface forces between clay particles which are intrinsically ion-specific. When charged surfaces strongly confine ions and water, the amplitude and oscillations of the net pressure naturally emerge from the interplay of electrostatics and steric effects, which cannot be captured by existing theories. Increasing confinement and surface charge densities promote ion-water structures that increasingly deviate from the ions' bulk hydration shells, being strongly anisotropic, persistent, and self-organizing into optimized, nearly solid-like assemblies where hardly any free water is left. Under these conditions, strongly attractive interactions can prevail between charged surfaces because of the dramatically reduced dielectric screening of water and the highly organized water-ion structures. By unravelling the ion-specific nature of these nanoscale interactions, we provide evidence that ion-specific solvation structures determined by confinement are at the origin of ion specificity in clays and potentially a broader range of confined aqueous systems.
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Affiliation(s)
- Francis Dragulet
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Abhay Goyal
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States.,Infrastructure Materials Group, Engineering Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Katerina Ioannidou
- Laboratoire de Mécanique et Génie Civil, CNRS Université de Montpellier, Montpellier 34090, France
| | - Roland J-M Pellenq
- EPiDaPo, The Joint CNRS and George Washington University Laboratory, Children's National Medical Center, Children's Research Institute, 111 Michigan Avenue NW, Washington, D.C. 20010, United States
| | - Emanuela Del Gado
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
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Palaia I, Goyal A, Del Gado E, Šamaj L, Trizac E. Like-Charge Attraction at the Nanoscale: Ground-State Correlations and Water Destructuring. J Phys Chem B 2022; 126:3143-3149. [PMID: 35420420 DOI: 10.1021/acs.jpcb.2c00028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Like-charge attraction, driven by ionic correlations, challenges our understanding of electrostatics both in soft and hard matter. For two charged planar surfaces confining counterions and water, we prove that, even at relatively low correlation strength, the relevant physics is the ground-state one, oblivious of fluctuations. Based on this, we derive a simple and accurate interaction pressure that fulfills known exact requirements and can be used as an effective potential. We test this equation against implicit-solvent Monte Carlo simulations and against explicit-solvent simulations of cement and several types of clays. We argue that water destructuring under nanometric confinement drastically reduces dielectric screening, enhancing ionic correlations. Our equation of state at reduced permittivity therefore explains the exotic attractive regime reported for these materials, even in the absence of multivalent counterions.
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Affiliation(s)
- Ivan Palaia
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Abhay Goyal
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets, N.W., Washington, D.C. 20057, United States
| | - Emanuela Del Gado
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets, N.W., Washington, D.C. 20057, United States
| | - Ladislav Šamaj
- Institute of Physics, Slovak Academy of Sciences, 84511 Bratislava, Slovakia
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10
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Varela L, Andraus S, Trizac E, Téllez G. Relaxation dynamics of two interacting electrical double-layers in a 1D Coulomb system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:394001. [PMID: 34233303 DOI: 10.1088/1361-648x/ac1237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/07/2021] [Indexed: 06/13/2023]
Abstract
We consider an out-of-equilibrium one-dimensional model for two electrical double-layers. With a combination of exact calculations and Brownian dynamics simulations, we compute the relaxation time (τ) for an electroneutral salt-free suspension, made up of two fixed colloids, withNneutralizing mobile counterions. ForNodd, the two double-layers never decouple, irrespective of their separationL; this is the regime of like-charge attraction, whereτexhibits a diffusive scaling inL2for largeL. On the other hand, for evenN,Lno longer is the relevant length scale for setting the relaxation time; this role is played by the Bjerrum length. This leads to distinctly different dynamics: forNeven, thermal effects are detrimental to relaxation, increasingτ, while they accelerate relaxation forNodd. Finally, we also show that the mean-field theory is recovered for largeNand moreover, that it remains an operational treatment down to relatively small values ofN(N> 3).
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Affiliation(s)
- Lucas Varela
- Departamento de Física, Universidad de los Andes, Bogotá, Colombia
- Université Paris-Saclay, CNRS, LPTMS, 91405, Orsay, France
| | - Sergio Andraus
- Graduate School of Physics, The University of Tokyo, Tokyo 113-0033, Japan
| | | | - Gabriel Téllez
- Departamento de Física, Universidad de los Andes, Bogotá, Colombia
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