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Ding Y, Yang J, Wang C, Wang Z, Li J, Hu B, Xia C. Structural Transformation between a Nematic Loose Packing and a Randomly Stacked Close Packing of Granular Disks. PHYSICAL REVIEW LETTERS 2023; 131:098202. [PMID: 37721830 DOI: 10.1103/physrevlett.131.098202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 06/29/2023] [Indexed: 09/20/2023]
Abstract
Packing structures of granular disks are reconstructed using magnetic resonance imaging techniques. As packing fraction increases, the packing structure transforms from a nematic loose packing to a dense packing with randomly oriented stacks. According to our model based on Edwards' volume ensemble, stack structures are statistically favored when the effective temperature decreases, which has a lower structural anisotropy than single disks, and brings down the global orientational order consequently. This mechanism identified in athermal granular materials can help us understand the nonergodic characteristics of disklike particle assemblies such as discotic mesogens and clays.
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Affiliation(s)
- Yunhao Ding
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Jing Yang
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Chenyang Wang
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Zhichao Wang
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Jianqi Li
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Bingwen Hu
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Chengjie Xia
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
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2
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Benselfelt T, Kummer N, Nordenström M, Fall AB, Nyström G, Wågberg L. The Colloidal Properties of Nanocellulose. CHEMSUSCHEM 2023; 16:e202201955. [PMID: 36650954 DOI: 10.1002/cssc.202201955] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/16/2023] [Indexed: 06/17/2023]
Abstract
Nanocelluloses are anisotropic nanoparticles of semicrystalline assemblies of glucan polymers. They have great potential as renewable building blocks in the materials platform of a more sustainable society. As a result, the research on nanocellulose has grown exponentially over the last decades. To fully utilize the properties of nanocelluloses, a fundamental understanding of their colloidal behavior is necessary. As elongated particles with dimensions in a critical nanosize range, their colloidal properties are complex, with several behaviors not covered by classical theories. In this comprehensive Review, we describe the most prominent colloidal behaviors of nanocellulose by combining experimental data and theoretical descriptions. We discuss the preparation and characterization of nanocellulose dispersions, how they form networks at low concentrations, how classical theories cannot describe their behavior, and how they interact with other colloids. We then show examples of how scientists can use this fundamental knowledge to control the assembly of nanocellulose into new materials with exceptional properties. We hope aspiring and established researchers will use this Review as a guide.
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Affiliation(s)
- Tobias Benselfelt
- Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
- Wallenberg Wood Science Center, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
- School of Materials Science and Engineering, Nanyang Technological University, 639798, Singapore, Singapore
| | - Nico Kummer
- Laboratory for Cellulose & Wood Materials, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
- Department of Health Sciences and Technology, ETH Zürich, 8092, Zürich, Switzerland
| | - Malin Nordenström
- Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
- Wallenberg Wood Science Center, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
| | | | - Gustav Nyström
- Laboratory for Cellulose & Wood Materials, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
- Department of Health Sciences and Technology, ETH Zürich, 8092, Zürich, Switzerland
| | - Lars Wågberg
- Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
- Wallenberg Wood Science Center, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
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3
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Que X, Jin Z, Hou Y, Zhou Y, Zhang Y. Experimental Study on the Time-Dependent Characteristics of MLPS Transparent Soil Strength. MATERIALS 2022; 15:ma15144990. [PMID: 35888457 PMCID: PMC9317852 DOI: 10.3390/ma15144990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/02/2022] [Accepted: 07/13/2022] [Indexed: 01/27/2023]
Abstract
The time-dependent characteristics of transparent soil strength, composed of magnesium lithium phyllosilicate, is important for applying a thixotropic clay surrogate. The gas injection method was employed to obtain the strength, represented as cracking pressure, which was then correlated to variables including rest time, disturbance time, and recovery time. Three concentrations (3, 4, and 5%) were tested. The results show that the strength was directly proportional to the rest time, recovery time, and concentration while the disturbance time reversed. The calculated limit strengths for 3%, 4%, and 5% transparent soils were 3.831 kPa, 8.849 kPa, and 12.048 kPa, respectively. Experimental data also showed that the residual strength for higher concentration transparent soil was more significant than the lower ones. The elastic property immediately generated partial strength recovery after disturbance, while the viscosity property resulted in a slow recovery stage similar to the rest stage. The strength recovery rate was also sensitive to concentration. Furthermore, the strength with 3%, 4%, and 5% concentrations could regain limit values after sufficient recovery, which were calculated as 4.303 kPa, 8.255 kPa, and 14.884 kPa, respectively.
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Perdomo-Pérez R, Martínez-Rivera J, Palmero-Cruz NC, Sandoval-Puentes MA, Gallegos JAS, Lázaro-Lázaro E, Valadez-Pérez NE, Torres-Carbajal A, Castañeda-Priego R. Thermodynamics, static properties and transport behaviour of fluids with competing interactions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:144005. [PMID: 35026739 DOI: 10.1088/1361-648x/ac4b29] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/13/2022] [Indexed: 06/14/2023]
Abstract
Competing interaction fluids have become ideal model systems to study a large number of phenomena, for example, the formation of intermediate range order structures, condensed phases not seen in fluids driven by purely attractive or repulsive forces, the onset of particle aggregation under in- and out-of-equilibrium conditions, which results in the birth of reversible and irreversible aggregates or clusters whose topology and morphology depend additionally on the thermodynamic constrictions, and a particle dynamics that has a strong influence on the transport behaviour and rheological properties of the fluid. In this contribution, we study a system of particles interacting through a potential composed by a continuous succession of a short-ranged square-well (SW), an intermediate-ranged square-shoulder and a long-ranged SW. This potential model is chosen to systematically analyse the contribution of every component of the interaction potential on the phase behaviour, the microstructure, the morphology of the resulting aggregates and the transport phenomena of fluids described by competing interactions. Our results indicate that the inclusion of a barrier and a second well leads to new and interesting effects, which in addition result in variations of the physical properties associated to the competition among interactions.
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Affiliation(s)
- Román Perdomo-Pérez
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico
| | - Jaime Martínez-Rivera
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico
| | - Norma C Palmero-Cruz
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico
| | - Miguel A Sandoval-Puentes
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico
| | - Javier A S Gallegos
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico
| | - Edilio Lázaro-Lázaro
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico
| | - Néstor E Valadez-Pérez
- Facultad de Ciencias en Física y Matemáticas, Universidad Autónoma de Chiapas, Carretera Emiliano Zapata km 8, 29050 Tuxtla Gutiérrez, Mexico
| | - Alexis Torres-Carbajal
- Unidad Profesional Interdisciplinaria de Ingeniería, Campus Tlaxcala, Instituto Politécnico Nacional. Plaza Bicentenario, Guillermo Valle 11, Centro, 9000 Tlaxcala de Xicohténcatl, Tlaxcala, México
| | - Ramón Castañeda-Priego
- Departamento de Ingeniería Física, División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico
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Talló K, Pons R, González C, López O. Monitoring the formation of a colloidal lipid gel at the nanoscale: vesicle aggregation driven by a temperature-induced mechanism. J Mater Chem B 2021; 9:7472-7481. [PMID: 34551044 DOI: 10.1039/d1tb01020d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Colloidal gels made of lipid vesicles at highly diluted conditions have been recently described. The structure and composition of this type of material could be especially relevant for studies that combine model lipid membranes with proteins, peptides, or enzymes to replicate biological conditions. Details about the nanoscale events that occur during the formation of such gels would motivate their future application. Thus, in this work we investigate the gelation mechanism, which consists of a lipid dispersion of vesicles going through a process that involves freezing and heating. The appropriate combination of techniques (transmission electron microscopy, differential scanning calorimetry and synchrotron small angle X-ray scattering) allowed in-depth analysis of the different events that give rise to the formation of the gel. Results showed how freezing damaged the lipid dispersion, causing a polydisperse suspension of membrane fragments and vesicles upon melting. Heating above the lipids' main phase transition temperature promoted the formation of elongated tubular structures. After cooling, these lipid tubes broke down into vesicles that formed branched aggregates across the aqueous phase, obtaining a material with gel characteristics. These mechanistic insights may also allow finding new ways to interact with lipid vesicles to form structured materials. Future works might complement the presented results with molecular dynamics or nuclear magnetic resonance experiments.
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Affiliation(s)
- Kirian Talló
- Department of Surfactants and Nanobiotechnology, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), C/Jordi Girona 18-26, 08034 Barcelona, Spain.
| | - Ramon Pons
- Department of Surfactants and Nanobiotechnology, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), C/Jordi Girona 18-26, 08034 Barcelona, Spain.
| | - César González
- Department of Surfactants and Nanobiotechnology, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), C/Jordi Girona 18-26, 08034 Barcelona, Spain.
| | - Olga López
- Department of Surfactants and Nanobiotechnology, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), C/Jordi Girona 18-26, 08034 Barcelona, Spain.
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Porpora G, Rusciano F, Guida V, Greco F, Pastore R. Understanding charged vesicle suspensions as Wigner glasses: dynamical aspects. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:104001. [PMID: 33246318 DOI: 10.1088/1361-648x/abce6f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Suspensions of charged vesicles in water with added salt are widespread in nature and industrial production. Here we investigate, via Brownian dynamics simulations, a model that grasps the key features of these systems, with bidisperse colloidal beads interacting via a hard-core and an electrostatic double layer potential. Our goal is to focus on a set of interaction parameters that is not generic but measured in recent experiments, and relevant for a class of consumer products, such as liquid fabric softeners. On increasing the volume fraction in a range relevant to real formulation, we show that the dynamics become progressively slower and heterogeneous, displaying the typical signatures of an approaching glass transition. On lowering the salt concentration, which corresponds to increasing the strength and range of the electrostatic repulsion, the emergence of glassy dynamics becomes significantly steeper, and, remarkably, occurs at volume fractions well below the hard-sphere glass transition. The volume fraction dependence of the structural relaxation time at different salt concentration is well described through a functional law inspired by a recently proposed model (Krausser et al 2015 Proc. Natl Acad. Sci. USA 112 13762). According to our results, the investigated system may be thought of as a Wigner glass, i.e. a low-density glassy state stabilized by long-range repulsive interactions. Overall, our study suggests that glassy dynamics plays an important role in controlling the stability of these suspensions.
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Affiliation(s)
- G Porpora
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, Naples 80125, Italy
| | - F Rusciano
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, Naples 80125, Italy
| | - V Guida
- The Procter and Gamble Company, Brussels Innovation Center, 1853 Strombeek Bever Temselaan 100, 1853 Grimbergen, Belgium
| | - F Greco
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, Naples 80125, Italy
| | - R Pastore
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, Naples 80125, Italy
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Suman K, Mittal M, Joshi YM. Effect of sodium pyrophosphate and understanding microstructure of aqueous LAPONITE ® dispersion using dissolution study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:224002. [PMID: 32015220 DOI: 10.1088/1361-648x/ab724d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this work, we investigate the physical origin of ergodicity breaking in an aqueous colloidal dispersion of synthetic hectorite clay, LAPONITE®, by performing dissolution and rheological experiments with monovalent salt and tetrasodium pyrophosphate solution. We also study the effect of pH and nature of interface, nitrogen and paraffin oil on the same. Dissolution experiments carried out for dispersions with both the interfaces show similar results. However, for samples with a nitrogen interface, all the effects are observed to get expedited in time compared to a paraffin oil interface. When kept in contact with water, 1.5 wt.% and 2.8 wt.% colloidal dispersion at pH 10 swells at small ages, while it does not swell at large ages. The solution of tetrasodium pyrophosphate, interestingly, dissolves the entire colloidal dispersion sample with pH 10 irrespective of the concentration of clay. Experiments carried out on colloidal dispersions prepared in water having pH 13 demonstrate no effect of water as well as sodium pyrophosphate solution on the same suggesting a possibility of the presence of negative charge on edge at that pH. We believe that all the behaviors observed for samples at pH 10 can be explained by an attractive gel microstructure formed by edge-to-face contact. Furthermore, the absence of swelling in old colloidal dispersion at pH 10 and dissolution of the same by sodium pyrophosphate solution cannot be explained by merely repulsive interactions. This behavior suggests that attractive interactions originating from edge-to-face contact play an important role in causing ergodicity breaking in the colloidal dispersions at pH 10 at all the ages irrespective of the clay concentration. We further substantiate the presence of a fractal network structure formed by interparticle edge-face association using rheological tools and cryo-TEM imaging. We also conduct a comprehensive study of the effect of tetrasodium pyrophosphate on the sol-gel transition of LAPONITE® dispersion.
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Affiliation(s)
- Khushboo Suman
- Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, India
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Motta RJB, Almeida AZF, de Lima BLB, Schneider R, Balaban RDC, van Duijneveldt JS, de Oliveira RJ. Polyphosphates can stabilize but also aggregate colloids. Phys Chem Chem Phys 2019; 22:15-19. [PMID: 31815261 DOI: 10.1039/c9cp05225a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phosphates are well known as dispersants for a variety of colloidal particles. Here however we use rheological measurements to show that high molecular weight polyphosphates (PP) can instead act as a flocculant for LAPONITE® clay platelets. The proposed mechanism is bridging of PP between clay particle edges, leading to highly charged clusters forming a Wigner glass. Dynamic light scattering shows a bimodal cluster size distribution, independent of PP molecular weight, but the highest molecular weight gave the highest viscous and loss moduli for the PP-clay solid. These unique all-inorganic solids may have application in solid-state ionic conducting materials, controlled release fertilizers and biomedical applications.
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Affiliation(s)
- Rayssa Jossanea Brasileiro Motta
- Physical Chemistry of Materials Group, Departamento de Química, Universidade Estadual da Paraíba, Campina Grande, PB 58429-500, Brazil.
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9
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Pujala RK, Bohidar HB. Hierarchical self-assembly, spongy architecture, liquid crystalline behaviour and phase diagram of Laponite nanoplatelets in alcohol-water binary solvents. J Colloid Interface Sci 2019; 554:731-742. [PMID: 31374517 DOI: 10.1016/j.jcis.2019.07.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/10/2019] [Accepted: 07/15/2019] [Indexed: 10/26/2022]
Abstract
Hydrophobicity and solvation of different charged species are among the various key factors that regulate the self-assembly of colloids, and macromolecules in their suspensions. In this paper, we demonstrate a method to tune the interaction potential and the resulting phase behaviour and microstructure of the states that form by using a combination of Laponite nanoplatelets and alcohols in water. This allows us to exquisitely control the self-assembly process of Laponite nanoplatelets. A new class of soft materials, called nanoclay-organogels, is studied systematically for their aging behaviour, microscopic structure and mechanical properties. Real space imaging techniques depicted spongy architecture with nano and micron size pores inside the gel matrix indicating the hierarchical self-assembly of the nanoplatelets in the aqueous solutions of polar organics. We have extensively examined the dispersion stability, aggregation, gelation and liquid crystalline behaviour of Laponite nanoplatelets in different alcohol (methanol, ethanol, 1-proponaol and ethylene glycol, and glycerol)-water binary solvents, thereby proposing a generalized description of nanoclay in alcoholic solutions, which is poorly probed and marginally understood in the literature. A phase diagram of Laponite® in alcohol solutions is proposed, which clearly demarcates regions of isotropic sol, unstable sol, isotropic gel, nematic/birefringent gel, glass, flocculated sedimentation and liquid crystalline structures.
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Affiliation(s)
- Ravi Kumar Pujala
- Soft and Active Matter Group, Department of Physics, Indian Institute of Science Education and Research (IISER) Tirupati, Andhra Pradesh 517507, India.
| | - H B Bohidar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
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Rey C, Hengl N, Baup S, Karrouch M, Dufresne A, Djeridi H, Dattani R, Pignon F. Velocity, stress and concentration fields revealed by micro-PIV and SAXS within concentration polarization layers during cross-flow ultrafiltration of colloidal Laponite clay suspensions. J Memb Sci 2019. [DOI: 10.1016/j.memsci.2019.02.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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11
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Liu Y, Xi Y. Colloidal systems with a short-range attraction and long-range repulsion: Phase diagrams, structures, and dynamics. Curr Opin Colloid Interface Sci 2019; 39. [PMID: 34140838 DOI: 10.1016/j.cocis.2019.01.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Colloidal systems with both a short-range attraction and long-range repulsion (SALR) have rich phases compared with the traditional hard sphere systems or sticky hard sphere systems. The competition between the short-range attraction and long-range repulsion results in the frustrated phase separation, which leads to the formation of intermediate range order (IRO) structures and introduces new phases to both equilibrium and nonequilibrium phase diagrams, such as clustered fluid, cluster percolated fluid, Wigner glass, and cluster glass. One hallmark feature of many SALR systems is the appearance of the IRO peak in the interparticle structure factor, which is associated with different types of IRO structures. The relationship between the IRO peak and the clustered fluid state has been careful investigated. Not surprisingly, the morphology of clusters in solutions can be affected and controlled by the SALR potential. And the effect of the SALR potential on the dynamic properties is also reviewed here. Even though much progress has been made in understanding SALR systems, many future works are still needed to have quantitative comparisons between experiments and simulations/theories and understand the differences from different experimental systems. Owing to the large parameter space available for SALR systems, many exciting features of SALR systems are not fully explored yet. Because proteins in low-salinity solutions have SALR interactions, the understanding of SALR systems can greatly help understand protein behavior in concentrated solutions or crowded conditions.
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Affiliation(s)
- Yun Liu
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.,Department of Chemical & Biomolecular Engineering, University of Delaware, Newark, DE, 19716, USA.,Department of Physics & Astronomy, University of Delaware, Newark, DE, 19716, USA
| | - Yuyin Xi
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.,Department of Chemical & Biomolecular Engineering, University of Delaware, Newark, DE, 19716, USA
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Suman K, Joshi YM. Microstructure and Soft Glassy Dynamics of an Aqueous Laponite Dispersion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:13079-13103. [PMID: 30180583 DOI: 10.1021/acs.langmuir.8b01830] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Synthetic hectorite clay Laponite RD/XLG is composed of disk-shaped nanoparticles that acquire dissimilar charges when suspended in an aqueous medium. Owing to their property to spontaneously self-assemble, Laponite is used as a rheology modifier in a variety of commercial water-based products. In particular, an aqueous dispersion of Laponite undergoes a liquid-to-solid transition at about 1 vol % concentration. The evolution of the physical properties as the dispersion transforms to the solid state is reminiscent of physical aging in molecular as well as colloidal glasses. The corresponding soft glassy dynamics of an aqueous Laponite dispersion, including the rheological behavior, has been extensively studied in the literature. In this feature article, we take an overview of recent advances in understanding soft glassy dynamics and various efforts taken to understand the peculiar rheological behavior. Furthermore, the continuously developing microstructure that is responsible for the eventual formation of a soft solid state that supports its own weight against gravity has also been a topic of intense debate and discussion. In particularly, extensive experimental and theoretical studies lead to two types of microstructures for this system: an attractive gel-like or a repulsive glass-like structure. We carefully examine and critically analyze the literature and propose a state (phase) diagram that suggests an aqueous Laponite dispersion to be present in an attractive gel state.
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Affiliation(s)
- Khushboo Suman
- Department of Chemical Engineering , Indian Institute of Technology Kanpur , India
| | - Yogesh M Joshi
- Department of Chemical Engineering , Indian Institute of Technology Kanpur , India
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Shi P, Kim YH, Mousa M, Sanchez RR, Oreffo ROC, Dawson JI. Self-Assembling Nanoclay Diffusion Gels for Bioactive Osteogenic Microenvironments. Adv Healthc Mater 2018; 7:e1800331. [PMID: 29911340 DOI: 10.1002/adhm.201800331] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Indexed: 11/08/2022]
Abstract
Laponite nanoparticles have attracted attention in the tissue engineering field for their protein interactions, gel-forming properties, and, more recently, osteogenic bioactivity. Despite growing interest in the osteogenic properties of Laponite, the application of Laponite colloidal gels to host the osteogenic differentiation of responsive stem cell populations remains unexplored. Here, the potential to harness the gel-forming properties of Laponite to generate injectable bioactive microenvironments for osteogenesis is demonstrated. A diffusion/dialysis gelation method allows the rapid formation of stable transparent gels from injectable, thixotropic Laponite suspensions in physiological fluids. Upon contact with buffered saline or blood serum, nanoporous gel networks exhibiting, respectively, fivefold and tenfold increases in gel stiffness are formed due to the reorganization of nanoparticle interactions. Laponite diffusion gels are explored as osteogenic microenvironments for skeletal stem cell containing populations. Laponite films support cell adhesion, proliferation, and differentiation of human bone marrow stromal cells in 2D. Laponite gel encapsulation significantly enhances osteogenic protein expression compared with 3D pellet culture controls. In both 2D and 3D conditions, cell associated mineralization is strongly enhanced. This study demonstrates that Laponite diffusion gels offer considerable potential as biologically active and clinically relevant bone tissue engineering scaffolds.
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Affiliation(s)
- Pujiang Shi
- Bone and Joint Research Group; Centre for Human Development; Stem Cells and Regeneration; Institute of Developmental Sciences; University of Southampton; Southampton SO16 6YD UK
| | - Yang-Hee Kim
- Bone and Joint Research Group; Centre for Human Development; Stem Cells and Regeneration; Institute of Developmental Sciences; University of Southampton; Southampton SO16 6YD UK
| | - Mohamed Mousa
- Bone and Joint Research Group; Centre for Human Development; Stem Cells and Regeneration; Institute of Developmental Sciences; University of Southampton; Southampton SO16 6YD UK
| | - Roxanna Ramnarine Sanchez
- Bone and Joint Research Group; Centre for Human Development; Stem Cells and Regeneration; Institute of Developmental Sciences; University of Southampton; Southampton SO16 6YD UK
| | - Richard O. C. Oreffo
- Bone and Joint Research Group; Centre for Human Development; Stem Cells and Regeneration; Institute of Developmental Sciences; University of Southampton; Southampton SO16 6YD UK
| | - Jonathan I. Dawson
- Bone and Joint Research Group; Centre for Human Development; Stem Cells and Regeneration; Institute of Developmental Sciences; University of Southampton; Southampton SO16 6YD UK
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Du M, Liu J, Clode PL, Leong YK. Surface chemistry, rheology and microstructure of purified natural and synthetic hectorite suspensions. Phys Chem Chem Phys 2018; 20:19221-19233. [PMID: 29987309 DOI: 10.1039/c8cp01382a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Natural (N-) and synthetic (S-) hectorite suspensions were found to display significant time-dependent rheology or ageing behaviour and shear thinning flow behaviour. The ageing behaviour was characterised by an increasing yield stress with rest time. The yield stress continued to increase even after a week of rest, a reflection of a long process. An open sponge-like cellular microstructure formed by platelet particles interacting attractively in the overlapping edge-face configuration was captured by cryo-SEM of gel samples prepared at high pressure (∼2000 bar) and subjected to rapid cryo-freezing, for both N- and S-hectorite gels. Even nano-discotic S-hectorite particles formed platelet particles hundreds of nanometres in length in the overlapping coin configuration. This structure, displaying a cell size ranging from tens to several hundred nanometres, is formed by strong attractive and repulsive forces. The platelets showed deformations such as bending and curling of the edges in response to these forces. The S-hectorite platelets are smaller and more rigid. During ageing the particles in the structure experience a net force. These particles will move in response causing force imbalance to be experienced by neighbouring particles and they will move in response. This action and reaction percolate through the network structure causing a high concentration of particles to respond. As a consequence the ageing process takes a long time to reach equilibrium. Various ageing models were used to fit the ageing data. The N-hectorite gels displayed a maximum yield stress at pH ∼ 8 and a particle zeta potential of -35 mV. This suggests the presence of critical positive and negative charge density is needed to form a structure with maximum strength. The zeta potential is negative and quite insensitive to pH from pH 4 to 12.
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Affiliation(s)
- Mingyong Du
- Department of Chemical Engineering, The University of Western Australia, Perth 6009, Australia.
| | - Jishan Liu
- Department of Chemical Engineering, The University of Western Australia, Perth 6009, Australia.
| | - Peta L Clode
- Centre for Microscopy, Characterization and Analysis, The University of Western Australia, Perth 6009, Australia
| | - Yee-Kwong Leong
- Department of Chemical Engineering, The University of Western Australia, Perth 6009, Australia.
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15
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Pujala RK, Schneijdenberg CTWM, van Blaaderen A, Bohidar HB. In-situ Observation of Hierarchical Self-Assembly Driven by Bicontinuous Gelation in Mixed Nanodisc Dispersions. Sci Rep 2018; 8:5589. [PMID: 29615709 PMCID: PMC5882853 DOI: 10.1038/s41598-018-23814-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 03/19/2018] [Indexed: 01/19/2023] Open
Abstract
The search for new functional soft materials with precise and reconfigurable structures at the nano and meso-scale is a major challenge as well as objective of the current science. Patchy colloids of different shapes and functionalities are considered important new building blocks of a bottom-up approach towards rational design of new soft materials largely governed by anisotropic interactions. Herein, we investigate the self-assembly, growth of hierarchical microstructures and aging dynamics of 2D nano-platelets of two different aspect ratios (Laponite ~25 and Montmorillonite ~250) which form gels with different porosity that is achieved by tuning their mixing ratios. Qualitative in situ real-space studies are carried out, including fluorescent confocal microscopy imaging of the bicontinuous gelation process or final states, which provides dynamic visualization of the self-organization. The bicontinuous gels exhibit a foam-like morphology having pores of a few micrometers in size that can be tuned by varying the mixing ratio of nanoplatelets. It is shown that this new class of clay gels has unique and tunable physical properties that will find potential applications in the development of low cost lithium ion batteries, nanocomposites and nuclear waste management.
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Affiliation(s)
- Ravi Kumar Pujala
- Soft Condensed Matter group, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC, Utrecht, The Netherlands. .,School of Physics, University of Hyderabad, Hyderabad, 500046, India. .,Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - C T W M Schneijdenberg
- Soft Condensed Matter group, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC, Utrecht, The Netherlands
| | - Alfons van Blaaderen
- Soft Condensed Matter group, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC, Utrecht, The Netherlands
| | - H B Bohidar
- Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.,Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi, 110067, India
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16
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Nordenström M, Fall A, Nyström G, Wågberg L. Formation of Colloidal Nanocellulose Glasses and Gels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:9772-9780. [PMID: 28853581 DOI: 10.1021/acs.langmuir.7b01832] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Nanocellulose (NC) suspensions can form rigid volume-spanning arrested states (VASs) at very low volume fractions. The transition from a free-flowing dispersion to a VAS can be the result of either an increase in particle concentration or a reduction in interparticle repulsion. In this work, the concentration-induced transition has been studied with a special focus on the influence of the particle aspect ratio and surface charge density, and an attempt is made to classify these VASs. The results show that for these types of systems two general states can be identified: glasses and gels. These NC suspensions had threshold concentrations inversely proportional to the particle aspect ratio. This dependence indicates that the main reason for the transition is a mobility constraint that, together with the reversibility of the transition, classifies the VASs as colloidal glasses. If the interparticle repulsion is reduced, then the glasses can transform into gels. Thus, depending on the preparation route, either soft and reversible glasses or stiff and irreversible gels can be formed.
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Affiliation(s)
- Malin Nordenström
- Department of Fibre and Polymer Technology and Wallenberg Wood Science Center, KTH Royal Institute of Technology , Teknikringen 56, SE-100 44 Stockholm, Sweden
| | - Andreas Fall
- Department of Fibre and Polymer Technology and Wallenberg Wood Science Center, KTH Royal Institute of Technology , Teknikringen 56, SE-100 44 Stockholm, Sweden
| | - Gustav Nyström
- Department of Health Science & Technology, ETH Zurich , Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Lars Wågberg
- Department of Fibre and Polymer Technology and Wallenberg Wood Science Center, KTH Royal Institute of Technology , Teknikringen 56, SE-100 44 Stockholm, Sweden
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17
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Thrithamara Ranganathan V, Bandyopadhyay R. Effects of aging on the yielding behaviour of acid and salt induced Laponite gels. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.03.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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18
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Marques FADM, Angelini R, Ruocco G, Ruzicka B. Isotopic Effect on the Gel and Glass Formation of a Charged Colloidal Clay: Laponite. J Phys Chem B 2017; 121:4576-4582. [PMID: 28376301 DOI: 10.1021/acs.jpcb.6b12596] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The time evolution of both dynamic and static structure factors of a charged colloidal clay, Laponite, dispersed in both H2O and D2O solvents has been investigated through multiangle dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) as a function of weight concentration. The aging phenomenology and the formation of arrested states, both gel and glass, are preserved in D2O, while the dynamics is slowed down with respect to water. These findings are important to understand the role played by the solvent in the interparticle interactions and for techniques such as neutron scattering and nuclear magnetic resonance that allow for the extension of the accessible scattering vectors and time scales.
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Affiliation(s)
| | - Roberta Angelini
- ISC-CNR, Sede Sapienza , I-00185 Roma, Italy.,Dipartimento di Fisica, Sapienza Università di Roma , I-00185 Roma, Italy
| | - Giancarlo Ruocco
- Dipartimento di Fisica, Sapienza Università di Roma , I-00185 Roma, Italy.,Center for Life Nano Science, IIT@Sapienza, Istituto Italiano di Tecnologia , Viale Regina Elena 291, 00161 Roma, Italy
| | - Barbara Ruzicka
- ISC-CNR, Sede Sapienza , I-00185 Roma, Italy.,Dipartimento di Fisica, Sapienza Università di Roma , I-00185 Roma, Italy
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19
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Griffiths S, Turci F, Royall CP. Local structure of percolating gels at very low volume fractions. J Chem Phys 2017; 146:014905. [DOI: 10.1063/1.4973351] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Joshi N, Rawat K, Aswal V, Bohidar H. Smoluchowski aggregation kinetics, gelation, ergodicity breaking and aging dynamics of (1:1) Laponite-Montmorillonite mixed clay dispersions. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.04.045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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21
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Benetatos P, Jho Y. Bundling in semiflexible polymers: A theoretical overview. Adv Colloid Interface Sci 2016; 232:114-126. [PMID: 26813628 DOI: 10.1016/j.cis.2016.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 12/07/2015] [Accepted: 01/02/2016] [Indexed: 01/07/2023]
Abstract
Supramolecular assemblies of polymers are key modules to sustain the structure of cells and their function. The main elements of these assemblies are charged semiflexible polymers (polyelectrolytes) generally interacting via a long(er)-range repulsion and a short(er)-range attraction. The most common supramolecular structure formed by these polymers is the bundle. In the present paper, we critically review some recent theoretical and computational advances on the problem of bundle formation, and point a few promising directions for future work.
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Affiliation(s)
- Panayotis Benetatos
- Department of Physics, Kyungpook National University, 80 Daehakro, Bukgu, Daegu, 702-701, South Korea
| | - YongSeok Jho
- Asia Pacific Center for Theoretical Physics, Pohang, Gyeongbuk, 790-784, South Korea; Department of Physics, Pohang University of Science and Technology, 790-784, South Korea.
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22
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Jatav S, Joshi YM. Analyzing a fractal gel of charged oblate nanoparticles in a suspension using time-resolved rheometry and DLVO theory. Faraday Discuss 2016; 186:199-213. [DOI: 10.1039/c5fd00128e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The disk-like nanoparticles of LAPONITE® are known to self-assemble to form a fractal gel within hours after a sufficiently large concentration of LAPONITE® is dispersed in water containing salt. The concentration of sodium counterions associated with LAPONITE® particles, however, continues to increase over a period of days, suggesting that delamination of LAPONITE® disks from stacks is sluggish and/or dissociation of counterions is slow. In either case, spontaneous self-assembly of LAPONITE® particles occurs even though delamination and/or counterion dissociation has not reached its equilibrium state. In order to determine the nature of the fractal gel as the extent of delamination and/or dissociation progresses towards equilibrium, we subject the LAPONITE® suspension to a freezing–defrosting cycle, which interestingly reinitiates the gelation process in suspension afresh. Application of time-resolved rheometry to a defrosted suspension shows that iso-frequency loss tangent curves intersect at an identical point, validating the Winter–Chambon criterion for a critical fractal gel state. Interestingly, while the time required to form a critical gel is observed to decrease with increased time elapsed since preparation, at which freezing–defrosting is carried out, the fractal dimension of the critical gel is observed to remain unaffected. We also solve DLVO theory for free energy interactions between the negatively charged LAPONITE® particle faces and analyze the observed phenomena.
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Affiliation(s)
- Shweta Jatav
- Department of Chemical Engineering
- Indian Institute of Technology, Kanpur
- Kanpur-208016
- India
| | - Yogesh M. Joshi
- Department of Chemical Engineering
- Indian Institute of Technology, Kanpur
- Kanpur-208016
- India
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23
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Godfrin PD, Hudson SD, Hong K, Porcar L, Falus P, Wagner NJ, Liu Y. Short-Time Glassy Dynamics in Viscous Protein Solutions with Competing Interactions. PHYSICAL REVIEW LETTERS 2015; 115:228302. [PMID: 26650319 DOI: 10.1103/physrevlett.115.228302] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Indexed: 06/05/2023]
Abstract
The glass transition of colloidal dispersions interacting with both a short-ranged attraction and long-ranged repulsion is studied using highly purified lysozyme solutions. Newtonian liquid behavior is observed at all conditions while measurements of the dynamics in the short-time limit show features typical of glassy colloidal systems at high protein concentrations. This interesting behavior is due to the competition of the attraction and repulsion that produces a heterogeneous microstructure only at intermediate range length scales. The results demonstrate that theories for the macroscopic properties of systems with competing interactions need to include intermediate range order.
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Affiliation(s)
- P Douglas Godfrin
- Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA
| | - Steven D Hudson
- Polymers and Complex Fluids Group, NIST, Gaithersburg, Maryland 20899, USA
| | - Kunlun Hong
- Center for Nanophase Materials and Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Lionel Porcar
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble cedex 9, France
| | - Peter Falus
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble cedex 9, France
| | - Norman J Wagner
- Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA
| | - Yun Liu
- Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA
- Center for Neutron Research, NIST, Gaithersburg, Maryland 20899, USA
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24
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25
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Ganley WJ, van Duijneveldt JS. Controlling Clusters of Colloidal Platelets: Effects of Edge and Face Surface Chemistries on the Behavior of Montmorillonite Suspensions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4377-4385. [PMID: 25815435 DOI: 10.1021/acs.langmuir.5b00047] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The structural and rheological consequences of adsorbing pyrophosphate anions to the edges and polyetheramines to the faces of montmorillonite platelets in aqueous suspension were investigated. Oscillatory rheology and scattering experiments showed that the two surface treatments act in different regions of the phase diagram and that this can be attributed to modifications of local particle interactions resulting in changes to the behavior and morphology of platelet clusters. The polyetheramine was found to neutralize surface charge, reducing electrostatic repulsion between platelets and therefore allowing them to come into closer proximity. This reduces the effective volume fraction of the clusters and reverses jamming in low ionic strength arrested phases. Conversely, the adsorption of pyrophosphate was found to introduce a high concentration of negative charge to the particle edge, resisting the formation of bonded percolating gels at high ionic strength. The two separate surface chemistries can be applied in parallel with no adverse effects and thus have the potential to be applied to dual functionalization of two-dimensional colloids such as platelets. This has implications for finer formulation design where targeted rheology modification could be achieved by careful selection of chemistry at one surface accompanied by an additional function at the other.
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Affiliation(s)
- William J Ganley
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
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26
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Saha D, Bandyopadhyay R, Joshi YM. Dynamic light scattering study and DLVO analysis of physicochemical interactions in colloidal suspensions of charged disks. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3012-3020. [PMID: 25726709 DOI: 10.1021/acs.langmuir.5b00291] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The interparticle interactions in colloidal suspensions of charged disks of Laponite clay in water were investigated using dynamic light scattering (DLS) and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. We studied the effects of clay concentration (C(L)), the concentration of externally added salt (C(S)), and temperature (T) on the microscopic dynamics of the clay suspensions. The fast (τ1) and mean slow relaxation times (⟨τ(ww)⟩) of Laponite suspensions were extracted from intensity autocorrelation functions measured at different waiting times (t(w)) after sample preparation. Comprehensive Laponite concentration-salt concentration-temperature-time superpositions of both the microscopic diffusive time scales and the stretching exponent corresponding to the slow relaxation process highlight the self-similar nature of the energy landscapes of the Laponite suspensions. The evolution of the sodium ion concentration in the aging suspension with tw, measured for several values of CL, CS, and T, was used in a DLVO analysis of the free energy of the suspension for two charged disks parallely approaching one another. This analysis confirms that, in addition to repulsive interparticle interactions, attractive interactions also play a pivotal role in the microscopic dynamics of spontaneously evolving Laponite suspensions.
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Affiliation(s)
- Debasish Saha
- †Soft Condensed Matter Group, Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560 080, India
| | - Ranjini Bandyopadhyay
- †Soft Condensed Matter Group, Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560 080, India
| | - Yogesh M Joshi
- ‡Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016, India
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27
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de Melo Marques FA, Angelini R, Zaccarelli E, Farago B, Ruta B, Ruocco G, Ruzicka B. Structural and microscopic relaxations in a colloidal glass. SOFT MATTER 2015; 11:466-471. [PMID: 25406421 DOI: 10.1039/c4sm02010c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The aging dynamics of a colloidal glass has been studied by multiangle dynamic light scattering, neutron spin echo, X-ray photon correlation spectroscopy and molecular dynamics simulations. The two relaxation processes, microscopic (fast) and structural (slow), have been investigated in an unprecedentedly wide range of time and length scales covering both ergodic and nonergodic regimes. The microscopic relaxation time remains diffusive at all length scales across the glass transition scaling with wavevector Q as Q(-2). The length-scale dependence of structural relaxation time changes from diffusive, characterized by a Q(-2)-dependence in the early stages of aging, to a Q(-1)-dependence in the full aging regime which marks a discontinuous hopping dynamics. Both regimes are associated with a stretched behaviour of the correlation functions. We expect these findings to provide a general description of both relaxations across the glass transition.
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Affiliation(s)
- Flavio Augusto de Melo Marques
- Center for Life Nano Science, IIT@Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena 291, I-00161 Roma, Italy.
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28
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Hierarchical self-assembly, relaxations and ergodic–non-ergodic transition in laponite ionogels. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2014.07.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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29
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Angelini R, Madsen A, Fluerasu A, Ruocco G, Ruzicka B. Aging behavior of the localization length in a colloidal glass. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2014.03.087] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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30
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Tudisca V, Bruni F, Scoppola E, Angelini R, Ruzicka B, Zulian L, Soper AK, Ricci MA. Neutron diffraction study of aqueous Laponite suspensions at the NIMROD diffractometer. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:032301. [PMID: 25314440 DOI: 10.1103/physreve.90.032301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Indexed: 06/04/2023]
Abstract
The process of dynamical arrest, leading to formation of different arrested states such as glasses and gels, along with the closely related process of aging, is central for both basic research and technology. Here we report on a study of the time-dependent structural evolution of two aqueous Laponite clay suspensions at different weight concentrations. Neutron diffraction experiments have been performed with the near and intermediate range order diffractometer (NIMROD) that allows studies of the structure of liquids and disordered materials over a continuous length scale ranging from 1 to 300 Å, i.e., from the atomistic to the mesoscopic scales. NIMROD is presently a unique diffractometer, bridging the length scales traditionally investigated by small angle neutron scattering or small angle x-ray scattering with that accessible by traditional diffractometers for liquids. Interestingly, we have unveiled a signature of aging of both suspensions in the length scale region of NIMROD. This phenomenon, ascribed to sporadic contacts between Laponite platelets at long times, has been observed with the sample arrested as gel or as repulsive glass. Moreover, water molecules within the layers closest to Laponite platelets surface show orientational and translational order, which maps into the crystalline structure of Laponite.
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Affiliation(s)
- V Tudisca
- Dipartimento di Scienze, Università degli Studi "Roma Tre", Via della Vasca Navale 84, 00146 Roma, Italy
| | - F Bruni
- Dipartimento di Scienze, Università degli Studi "Roma Tre", Via della Vasca Navale 84, 00146 Roma, Italy
| | - E Scoppola
- Dipartimento di Scienze, Università degli Studi "Roma Tre", Via della Vasca Navale 84, 00146 Roma, Italy
| | - R Angelini
- IPCF-CNR and Dipartimento di Fisica, Università di Roma "La Sapienza", Piazzale A. Moro 2, I-00185, Rome, Italy
| | - B Ruzicka
- IPCF-CNR and Dipartimento di Fisica, Università di Roma "La Sapienza", Piazzale A. Moro 2, I-00185, Rome, Italy
| | - L Zulian
- Dipartimento di Scienza dei Materiali, Università degli Studi Milano Bicocca, Via Roberto Cozzi, 53 20125 Milano, Italy
| | - A K Soper
- ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire, OX11 0QX, United Kingdom
| | - M A Ricci
- Dipartimento di Scienze, Università degli Studi "Roma Tre", Via della Vasca Navale 84, 00146 Roma, Italy
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31
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Morariu S, Bercea M, Sacarescu L. Tailoring of Clay/Poly(ethylene oxide) Hydrogel Properties by Chitosan Incorporation. Ind Eng Chem Res 2014. [DOI: 10.1021/ie501891t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Simona Morariu
- “Petru Poni” Institute
of Macromolecular Chemistry, 41-A Grigore
Ghica Voda Alley, 700487 Iasi, Romania
| | - Maria Bercea
- “Petru Poni” Institute
of Macromolecular Chemistry, 41-A Grigore
Ghica Voda Alley, 700487 Iasi, Romania
| | - Liviu Sacarescu
- “Petru Poni” Institute
of Macromolecular Chemistry, 41-A Grigore
Ghica Voda Alley, 700487 Iasi, Romania
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32
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Zulian L, Augusto de Melo Marques F, Emilitri E, Ruocco G, Ruzicka B. Dual aging behaviour in a clay-polymer dispersion. SOFT MATTER 2014; 10:4513-4521. [PMID: 24817524 DOI: 10.1039/c4sm00172a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Clay-polymer compounds have recently attracted increasing attention due to their intriguing physical properties in colloidal science and their rheological non-trivial behaviour in technological applications. Aqueous solutions of Laponite clay spontaneously age from a liquid up to an arrested state of different nature (gel or glass) depending on the colloidal volume fraction and ionic strength. We have investigated, through dynamic light scattering, how the aging dynamics of Laponite dispersions at fixed clay concentration (Cw = 2.0%) is modified by the addition of various amounts of poly(ethylene oxide) (PEO) (CPEO = (0.05 ÷ 0.50) %) at two different molecular weights (Mw = 100 kg mol(-1) and Mw = 200 kg mol(-1)). A surprising and intriguing phenomenon has been observed: the existence of a critical polymer concentration C that discriminates between two different aging dynamics. With respect to pure Laponite systems the aging will be assisted (faster) or hindered (slower) for PEO concentrations respectively lower (CPEO < C) or higher (CPEO > C) than the critical concentration. In this way a control on the aging dynamics of PEO-Laponite systems is obtained. A possible explanation based on the balance of competitive mechanisms related to the progressive saturation of the clay surface by polymers is proposed. This study shows how a real control on the aging speed of the PEO-Laponite system is at hand and renders possible a real control of the complex interparticle interaction potential.
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Affiliation(s)
- Laura Zulian
- Dipartimento di Scienza dei Materiali, Università degli Studi Milano Bicocca, Via Roberto Cozzi, 53 20125 Milano, Italy.
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33
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Joshi N, Rawat K, Bohidar HB. Coexistence of iso-nonergodic laponite gel and glass in 1-methyl-3-octylimidazolium chloride ionic liquid solutions. J Phys Chem B 2014; 118:6329-38. [PMID: 24821007 DOI: 10.1021/jp5032916] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We report unique colloidal gel-glass coexistence in aqueous laponite dispersion (2% w/v) in the presence of 1-methyl-3-octylimidazolium chloride ionic liquid (IL, [C8mim][Cl], concentration 0.01 to 0.05% w/v), where both of the phases had identical nonergodicity and were dynamically interactive. With aging, the nascent heterogeneous dispersion exhibited spontaneous two-phase separation, and the time-dependent relative viscosity followed: η(r) = |ε|(-k) where ε = (t - t(g))/t(g) and t(g) is the time required for the system to get arrested, with k decreasing from 3.13 to 2.54 as the IL concentration was increased from 0 to 0.03% (w/v), implying slowing down of the arrest kinetics. This time was measured from viscosity and rheology studies, revealing the formation of IL-mediated finite size colloidal networks on a time scale of ~4 × 10(3) s, whereas the dispersion developed a large viscosity one decade in time later (~4 × 10(4) s). Homogeneous transparent upper phase was an entropic glass and exhibited substantial storage modulus gain (300-3000 Pa) with an increase in IL concentration (0 to 0.05% (w/v)). The translucent lower gel phase had a much higher storage modulus. Dynamic light scattering measured bimodal relaxation time of concentration fluctuations. The degree of nonergodicity in the two phases was approximately the same, implying laponite-IL cluster exchange across the interface (identical slow-mode diffusivity). In summary, IL-induced first-order phase separation in laponite dispersion produced a homogeneous colloidal gel coexisting with a glass not commonly observed in soft matter systems. This implied that the two phases were dynamically coupled on long time scales, whereas their short-time behavior was distinctively different.
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Affiliation(s)
- Nidhi Joshi
- School of Physical Sciences and ‡Special Centre for Nanosciences, Jawaharlal Nehru University , New Mehrauli Road, New Delhi 110 067, India
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34
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Glass-glass transition during aging of a colloidal clay. Nat Commun 2014; 5:4049. [PMID: 24887086 DOI: 10.1038/ncomms5049] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 05/06/2014] [Indexed: 11/09/2022] Open
Abstract
Colloidal suspensions are characterized by a variety of microscopic interactions, which generate unconventional phase diagrams encompassing fluid, gel and glassy states and offer the possibility to study new phase and/or state transitions. Among these, glass-glass transitions are rare to be found, especially at ambient conditions. Here, through a combination of dilution experiments, X-ray photon correlation spectroscopy, small angle X-ray scattering, rheological measurements and Monte Carlo simulations, we provide evidence of a spontaneous glass-glass transition in a colloidal clay. Two different glassy states are distinguished with evolving waiting time: a first one, dominated by long-range screened Coulombic repulsion (Wigner glass) and a second one, stabilized by orientational attractions (Disconnected House of Cards glass), occurring after a much longer time. These findings may have implications for heterogeneously charged systems out-of-equilibrium and for applications where a fine control of the local order and/or long term stability of the amorphous materials are required.
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35
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Saha D, Joshi YM, Bandyopadhyay R. Investigation of the dynamical slowing down process in soft glassy colloidal suspensions: comparisons with supercooled liquids. SOFT MATTER 2014; 10:3292-3300. [PMID: 24637644 DOI: 10.1039/c4sm00187g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The primary and secondary relaxation timescales of aging colloidal suspensions of Laponite are estimated from intensity autocorrelation functions obtained in dynamic light scattering (DLS) experiments. The dynamical slowing down of these relaxation processes are compared with observations in fragile supercooled liquids by establishing a one-to-one mapping between the waiting time since filtration of a Laponite suspension and the inverse of the temperature of a supercooled liquid that is rapidly quenched towards its glass transition temperature. New timescales associated with primary and secondary relaxation processes, such as the characteristic timescale associated with the slowdown of the secondary relaxation process and the glass transition time, are extracted to describe the phenomenon of dynamical arrest in Laponite suspensions. In results that are strongly reminiscent of those extracted from supercooled liquids approaching their glass transitions, it is demonstrated that a strong coupling exists between the primary and secondary relaxation processes of aging Laponite suspensions in the cage-forming regime. Furthermore, the experimental data presented here clearly demonstrate the self-similar nature of the aging dynamics of Laponite suspensions within a range of sample concentrations.
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Affiliation(s)
- Debasish Saha
- Soft Condensed Matter Group, Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560 080, India.
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36
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Arfin N, Bohidar HB. Ergodic-to-nonergodic phase inversion and reentrant ergodicity transition in DNA-nanoclay dispersions. SOFT MATTER 2014; 10:149-156. [PMID: 24652438 DOI: 10.1039/c3sm52218k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We have observed DNA concentration and hydration dependent inversion from ergodic to non-ergodic phase followed by reentry into the ergodic phase in DNA-nanoclay (laponite) dispersions at room temperature (25 °C), using results obtained from dynamic light scattering (DLS) and rheology data. The interaction between the DNA strand and the anisotropically charged discotic platelets of laponite (L) was found to be strongly hierarchical in DNA concentration. For a fixed laponite concentration (CL = 1% (w/v)) and varying DNA concentration (CDNA) from 0.3-2.3% (w/v), we observed three distinct phase regions characterized by the following: region (i): CDNA < 1.0% (w/v), ergodic region with weak DNA-L attractive interaction, region (ii): 1.0% < CDNA < 1.6% (w/v), non-ergodic regime having strong DNA-L associative interaction and region (iii): CDNA > 1.6% (w/v), showing phase reentry into the ergodic regime due to repulsion between DNA strands. Hydration study in these three regions revealed that a loss in the abundance of amorphous water, signified by Raman frequency 3460 cm(-1), caused the ergodic to nonergodic phase transition. In summary, it is shown that maximum stability and interaction between DNA and nanoclay platelets occurred at an intermediate concentration of DNA where the hydration was at its minimum. The present system is qualitatively different from the hard-sphere/polymer systems for which reentrant phase transition has been reported in the literature. However, some similarity between the two classes of systems is not ruled out.
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Affiliation(s)
- Najmul Arfin
- Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India.
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37
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Kang H, Kirkpatrick TR, Thirumalai D. Manifestation of random first-order transition theory in Wigner glasses. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:042308. [PMID: 24229173 DOI: 10.1103/physreve.88.042308] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 07/21/2013] [Indexed: 06/02/2023]
Abstract
We use Brownian dynamics simulations of a binary mixture of highly charged spherical colloidal particles to test some of the predictions of the random first-order transition (RFOT) theory [Phys. Rev. Lett. 58, 2091 (1987); Phys. Rev. A 40, 1045 (1989)]. In accord with mode-coupling theory and RFOT, we find that as the volume fraction of the colloidal particles ϕ approaches the dynamical transition value ϕ(A), three measures of dynamics show an effective ergodic to nonergodic transition. First, there is a dramatic slowing down of diffusion, with the translational diffusion constant decaying as a power law as ϕ→ϕ(A)(-). Second, the energy metric, a measure of ergodicity breaking in classical many-body systems, shows that the system becomes effectively nonergodic as ϕ(A) is approached. Finally, the time t(*), at which the four-point dynamical susceptibility achieves a maximum, also increases as a power law near ϕ(A). Remarkably, the translational diffusion coefficients, ergodic diffusion coefficient, and (t(*))(-) all vanish as (ϕ(-1)-ϕ(A)(-1))(γ) with both ϕ(A)(≈0.1) and γ being the roughly the same for all three quantities. Above ϕ(A), transport involves crossing free energy barriers. In this regime, the density-density correlation function decays as a stretched exponential [exp-(t/τ(α))(β)] with β≈0.45. The ϕ dependence of the relaxation time τ(α) could be fit using the Vogel-Tamman-Fulcher law with the ideal glass transition at ϕ(K)≈0.47. By using a local entropy measure, we show that the law of large numbers is not obeyed above ϕ(A), and gives rise to subsample to subsample fluctuations in all physical observables. We propose that dynamical heterogeneity is a consequence of violation of law of large numbers.
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Affiliation(s)
- Hongsuk Kang
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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38
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Shahin A, Joshi YM. Physicochemical effects in aging aqueous Laponite suspensions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:15674-15686. [PMID: 23057660 DOI: 10.1021/la302544y] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We study aging behavior of an aqueous suspension of Laponite as a function of concentration of Laponite, concentration of salt, time elapsed since preparation of suspension (idle time), and temperature by carrying extensive rheological and conductivity experiments. We observe that temporal evolution of elastic moduli, which describes structural build-up and aging, shifts to low times for experiments carried out for higher concentration of Laponite, higher concentration of salt, greater temperature, and longer idle time while preserving the curvature of evolution in the solid regime (elastic modulus greater than viscous modulus). Consequently appropriate shifting of evolution of elastic modulus in the solid regime leads to aging time-idle time-salt concentration-Laponite concentration-temperature superposition. The existence of such a superposition suggests the generic nature of microstructure buildup irrespective of mentioned variables in the explored range. The behavior of shift factors needed to obtain the superposition indicate that the energy barrier associated with structural buildup decreases with an increase in idle time and temperature and decreases linearly with an increase in concentration of Laponite and that of salt. The conductivity experiments show that ionic conductivity of the suspension increases with increasing Laponite concentration, salt concentration, temperature, and very importantly the idle time. We also analyze the interparticle interactions using DLVO theory that suggests an increase in idle time, temperature, and salt concentration increases the height of the repulsive energy barrier while it decreases the width of the same when particles approach each other in a parallel fashion. However when particles approach each other in a perpendicular fashion, owing to dissimilar charges on edge and face, the energy barrier for the attractive interaction is expected to decrease with an increase in idle time, temperature, and salt concentration. Analysis of rheological and conductivity experiments suggests a strong influence of attractive interactions on the low energy structures in an aqueous suspension of Laponite.
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Affiliation(s)
- A Shahin
- Department of Chemical Engineering, Indian Institute of Technology Kanpur, India
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39
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Hansen EL, Hemmen H, Fonseca DM, Coutant C, Knudsen KD, Plivelic TS, Bonn D, Fossum JO. Swelling transition of a clay induced by heating. Sci Rep 2012; 2:618. [PMID: 22943004 PMCID: PMC3431542 DOI: 10.1038/srep00618] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 08/15/2012] [Indexed: 12/02/2022] Open
Abstract
Clays are of paramount importance for soil stability, but also in applications ranging from oil recovery to composites and hydrogels. Generically, clays are divided into two subclasses: macroscopically swelling, ‘active’ clays that have the capacity for taking up large amounts of water to form stable gels, and ‘passive’ or non-swelling clays; the former stabilize soils whereas the latter are known to lead to landslides. However, it has been unclear so far what mechanisms underlie clay swelling. Here, we report the first observation of a temperature-induced transition from a passive to an active, swelling clay. We propose a simple description of the swelling transition; while net attractive interactions are dominant at low temperatures so that the clay particles remain attached to each other in stacks, at higher temperatures it is energetically favourable for the clay to swell due to the entropy that is gained by counterions which are liberated during swelling.
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Affiliation(s)
- E L Hansen
- Department of Physics, Norwegian University of Science and Technology – NTNU, Trondheim, Norway.
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40
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Kleshchanok D, Meester V, Pompe CE, Hilhorst J, Lekkerkerker HNW. Effects of Added Silica Nanoparticles on Hectorite Gels. J Phys Chem B 2012; 116:9532-9. [DOI: 10.1021/jp302472e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dzina Kleshchanok
- Van
’t Hoff Laboratory, Debye Institute for
Nanomaterials Science, Utrecht University, The Netherlands
| | - Vera Meester
- Van
’t Hoff Laboratory, Debye Institute for
Nanomaterials Science, Utrecht University, The Netherlands
| | - Cornelia E. Pompe
- Van
’t Hoff Laboratory, Debye Institute for
Nanomaterials Science, Utrecht University, The Netherlands
| | - Jan Hilhorst
- Van
’t Hoff Laboratory, Debye Institute for
Nanomaterials Science, Utrecht University, The Netherlands
| | - Henk N. W. Lekkerkerker
- Van
’t Hoff Laboratory, Debye Institute for
Nanomaterials Science, Utrecht University, The Netherlands
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41
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Sun W, Yang Y, Wang T, Huang H, Liu X, Tong Z. Effect of adsorbed poly(ethylene glycol) on the gelation evolution of Laponite suspensions: Aging time-polymer concentration superposition. J Colloid Interface Sci 2012; 376:76-82. [DOI: 10.1016/j.jcis.2012.01.064] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 12/06/2011] [Accepted: 01/10/2012] [Indexed: 11/26/2022]
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42
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Shahin A, Joshi YM. Hyper-aging dynamics of nanoclay suspension. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:5826-5833. [PMID: 22414339 DOI: 10.1021/la205153b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Aqueous suspension of nanoclay Laponite undergoes structural evolution as a function of time, which enhances its elasticity and relaxation time. In this work, we employ an effective time approach to investigate long-term relaxation dynamics by carrying out creep experiments. Typically, we observe that the monotonic evolution of elastic modulus shifts to lower aging times, while maxima in viscous moduli get progressively broader for experiments carried out on a later date after preparation (idle time) of the nanoclay suspension. Application of effective time theory produces a superposition of all the creep curves irrespective of their initial state. The resulting dependence of the relaxation time on aging time shows very strong hyper-aging dynamics at short idle times, which progressively weakens to demonstrate a linear dependence in the limit of very long idle times. Remarkably, this behavior of nanoclay suspensions is akin to that observed for polymeric glasses. Consideration of aging as a first-order process suggests that continued hyper-aging dynamics causes cessation of aging. The dependence of relaxation time on aging time, therefore, must attenuate eventually producing linear or weaker dependence on time in order to approach a progressively low-energy state in the limit of very long times as observed experimentally. We also develop a simple scaling model based on a concept of aging of an energy well, which qualitatively captures various experimental observations very well, leading to profound insight into the hyper-aging dynamics of nanoclay suspensions.
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Affiliation(s)
- A Shahin
- Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur, India
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43
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Pignon F, Abyan M, David C, Magnin A, Sztucki M. In situ characterization by SAXS of concentration polarization layers during cross-flow ultrafiltration of Laponite dispersions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:1083-1094. [PMID: 22149238 DOI: 10.1021/la201492z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The structural organization inside the concentration polarization layer during cross-flow membrane separation process of Laponite colloidal dispersions has been characterized for the first time by in situ time-resolved small-angle X-ray scattering (SAXS). Thanks to the development of new "SAXS cross-flow filtration cells", concentration profiles have been measured as a function of the distance z from the membrane surface with 50 μm accuracy and linked to the permeation flux, cross-flow, and transmembrane pressure registered simultaneously. Different rheological behaviors (thixotropic gel with a yield stress or shear thinning sol) have been explored by controlling the mutual interactions between the particles as a result on the addition of peptizer. The structural reversibility of the concentration polarization layer has been demonstrated being in agreement with permeation flux measurements. These observations were related to structure of the dispersions under flow and their osmotic pressure.
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Affiliation(s)
- F Pignon
- Laboratoire de Rhéologie, Université Joseph Fourier - Grenoble I, Grenoble - Institut National Polytechnique, CNRS, UMR 5520, BP 53, F-38041 Grenoble Cedex 9, France.
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44
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Shahin A, Joshi YM, Ramakrishna SA. Interface-induced anisotropy and the nematic glass/gel state in jammed aqueous Laponite suspensions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:14045-14052. [PMID: 21995523 DOI: 10.1021/la202398v] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Aqueous suspensions of Laponite, a system composed of disklike nanoparticles, are found to develop optical birefringence over several days, well after the suspensions solidified because of jamming. The optical anisotropy is particularly enhanced near the air-Laponite suspension interface over length scales of several millimeters, which is beyond 5 orders of magnitude larger than the particle length scale, suggestive of large-scale ordering influenced by the interface. The orientational order increases with time and is always greater for higher concentration of salt, higher concentration of Laponite, and higher temperatures of the suspension. Although weakly birefringent, Laponite suspensions covered by paraffin oil do not show any enhancement in optical anisotropy near the interface compared to that in the bulk. We suggest that the expedited structure formation near the air interface propagating progressively inside the sample is responsible for the observed behavior. We discuss the observed nematic ordering in the context of glass-like and gel-like microstructure associated with aqueous Laponite suspensions.
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Affiliation(s)
- A Shahin
- Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, India
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45
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Unified scaling behavior of physical properties of clays in alcohol solutions. J Colloid Interface Sci 2011; 364:311-6. [DOI: 10.1016/j.jcis.2011.08.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 08/19/2011] [Accepted: 08/20/2011] [Indexed: 11/22/2022]
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46
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Yuan CN, Li YF, Sheng YJ, Tsao HK. Wet nanogranular materials: Colloidal glass and gel. J Chem Phys 2011; 135:174703. [DOI: 10.1063/1.3658501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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47
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Colombani J, Petit L, Ybert C, Barentin C. Probing the fluctuation-dissipation theorem in a Perrin-like experiment. PHYSICAL REVIEW LETTERS 2011; 107:130601. [PMID: 22026834 DOI: 10.1103/physrevlett.107.130601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 07/23/2011] [Indexed: 05/31/2023]
Abstract
In this Letter, we present a new experimental approach to investigate the effective temperature concept as a generalization of the fluctuation-dissipation theorem (FDT) for nonequilibrium systems. Simultaneous measurements of diffusion coefficient and sedimentation velocity of heavy colloids, embedded in a Laponite clay suspension, are performed with a fluorescence-recovery-based setup. This nonperturbative dual measurement, performed at a single time in a single sample, allows for a direct application of the FDT to the tracer velocity observable. It thus provides a well-defined derivation of the effective temperature in this ageing colloidal gel. For a wide range of concentrations and ageing times, we report no violation of the FDT, with effective temperature agreeing with bath temperature. This result is consistent with recent theoretical predictions on the coupling between the velocity observable and nonequilibrium gels dynamics.
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Affiliation(s)
- Jean Colombani
- Laboratoire de Physique de la Matière Condensée et Nanostructures, Université de Lyon, CNRS, UMR, Domaine scientifique de la Doua, Villeurbanne, France
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48
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Pujala RK, Pawar N, Bohidar HB. Landau theory description of observed isotropic to anisotropic phase transition in mixed clay gels. J Chem Phys 2011; 134:194904. [PMID: 21599085 DOI: 10.1063/1.3590028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A characteristic new cooperative dehydration transition, in 1:1 Laponite-MMT cogel, was observed at T(c) ≈ 60 °C, a temperature at which the storage modulus (G(')) and depolarization ratio (D(p)) showed sharp increase, and the isotropic cogel turned into an anisotropic one. The dehydration dynamics could be described through power-law relations: G(') ∼ (T(c)-T)(-γ) and D(p) ∼ (T(c)-T)(-β) with γ ≈ β = 0.40 ± 0.05. The x-ray diffraction data revealed that the crystallite size decreased from 17 nm (at 20 °C) to 10 nm (at 80 °C) implying loss of free and inter-planar water. When this cogel was spontaneously cooled below T(c), it exhibited much larger storage modulii values which implied the existence of several metastable states in this system. This phase transition could be modeled through Landau theory, where the depolarization ratio was used as experimental order parameter (ψ). This parameter was found to scale with temperature, as ψ ∼ (T(c)-T)(-α), with power-law exponent α = 0.40 ± 0.05; interestingly, we found α ≈ β ≈ γ.
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Affiliation(s)
- Ravi Kumar Pujala
- Nanomaterials and Nanocomposite Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India
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49
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Paineau E, Bihannic I, Baravian C, Philippe AM, Davidson P, Levitz P, Funari SS, Rochas C, Michot LJ. Aqueous suspensions of natural swelling clay minerals. 1. Structure and electrostatic interactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:5562-5573. [PMID: 21476528 DOI: 10.1021/la2001255] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this article, we present a general overview of the organization of colloidal charged clay particles in aqueous suspension by studying different natural samples with different structural charges and charge locations. Small-angle X-ray scattering experiments (SAXS) are first used to derive swelling laws that demonstrate the almost perfect exfoliation of clay sheets in suspension. Using a simple approach based on geometrical constraints, we show that these swelling laws can be fully modeled on the basis of morphological parameters only. The validity of this approach was further extended to other clay data from the literature, in particular, synthetic Laponite. For all of the investigated samples, experimental osmotic pressures can be properly described by a Poisson-Boltzmann approach for ionic strength up to 10(-3) M, which reveals that these systems are dominated by repulsive electrostatic interactions. However, a detailed analysis of the Poisson-Boltzmann treatment shows differences in the repulsive potential strength that are not directly linked to the structural charge of the minerals but rather to the charge location in the structure for tetrahedrally charged clays (beidellite and nontronites) undergoing stronger electrostatic repulsions than octahedrally charged samples (montmorillonites, laponite). Only minerals subjected to the strongest electrostatic repulsions present a true isotropic to nematic phase transition in their phase diagrams. The influence of ionic repulsions on the local order of clay platelets was then analyzed through a detailed investigation of the structure factors of the various clay samples. It appears that stronger electrostatic repulsions improve the liquidlike positional local order.
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Affiliation(s)
- Erwan Paineau
- Laboratoire Environnement et Minéralurgie, Nancy Université-CNRS, UMR 7569, BP40 54501 Vandœuvre Cedex, France.
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50
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Pujala RK, Pawar N, Bohidar HB. Universal sol state behavior and gelation kinetics in mixed clay dispersions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:5193-5203. [PMID: 21466239 DOI: 10.1021/la1048453] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Sol and gel state behavior, in aqueous salt free dispersions, of clays Laponite (L) and Na montmorillonite (MMT) was studied at various mixing ratios (L:MMT = r = 1:0.5, 1:1, and 1:2). In the sol state, the zeta potential and gelation concentration of L-MMT obeyed the universal relation, X(L-MMT) = (rX(L) + X(MMT))/(1 + r), where X is zeta potential or gelation concentration (c(g)), implying that these properties are linear combinations of the same of their individual components. The low frequency storage modulus (G(0)'), relative viscosity (η(r)), and apparent cluster size (R) could be universally described by the power-law, G(0)' ∼ ((c/c(g)) - 1)(t) (c > c(g)), and η(r), R ∼ (1 - (c/c(g)))(-k,ν) (c < c(g)), with t = 1.5, k = 1.1, and υ = 0.8 close to the gelation concentration, for r = 1:1 cogel, consistent with the percolation model description of gelation. Interestingly, the hyperscaling relation δ = t/(k + t) yielded δ = 0.56 not too different from the predicted value ∼0.7, while the experimental value of δ obtained from G''(ω) ∼ ω(δ) close to c ≈ c(g) yielded δ = 1.5, which was at variance with the hyperscaling result. The experimental data, on hand, mostly supported percolation type gelation mechanism. As the cogels were slowly heated, at a characteristic temperature, T(g), a sharp increase in G' value was noticed, implying a transition to gel hardening (a new phase state). The temperature-dependent behavior followed the power-law description, G' ∼ (T(g) - T)(-γ) (T < T(g)), with γ = 0.40 ± 0.05 invariant of composition of the cogel, whereas for MMT and Laponite, γ = 0.25 and 0.55, respectively. It has been shown that the cogel has significantly enhanced mechanical (G(0) increased by 10 times for r = 1:1 cogel) and thermal properties (T(g) increased by 13 °C for 1:1 cogel) that can be exploited to design customized soft materials.
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Affiliation(s)
- Ravi Kumar Pujala
- Nanomaterials and Nanocomposite Laboratory School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India
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