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Leong YK. Direct Evidence of Electric Double Layer (EDL) Repulsive Force Being Responsible for the Time-Dependent Behavior of Clay Gels in the Structural Rejuvenation Mode. J Phys Chem B 2024; 128:3784-3793. [PMID: 38593457 DOI: 10.1021/acs.jpcb.4c00858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
A strong EDL repulsive force is needed to accentuate the time-dependent behavior of charge and shape anisotropic clay gels at the stepdown shear rate. This force was strengthened by P2O74- adsorption, increasing the negative charge density of the clay particles. At the stepdown shear rate of 10 s-1, it is strong enough to disrupt the flow-aligned structure attained at 1000 s-1 and orient the particles to form more bonds. The resultant outcome is stepdown shear stress increasing with time until these structure disruption and bond formation processes reach an equilibrium state. The number of lower energy approach configurations (-ve face - +ve edge) for bonding is reduced by the strengthened EDL repulsive force, slowing the bonding process. The time to reach the equilibrium stepdown shear stress value increased initially and then decreased and became zero at a high negative charge density where the charge anisotropy of the particles no longer exists. The need of a sufficiently strong EDL repulsive force for the display of time-dependent behavior is true for all clay gels: Laponite, hectorite, NaMnt, sepiolite, and kaolin gels. The untreated NaMnt gel already displayed time-dependent behavior as its EDL repulsive force is sufficiently strong. The same EDL-control time-dependent behavior was obtained if pH was used to vary the negative charge density of the clay particles.
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Affiliation(s)
- Yee-Kwong Leong
- Department of Chemical Engineering, The University of Western Australia, Crawley 6009, Australia
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2
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Mohammed S, Liu M, Zhang Q, Narayanan S, Zhang F, Gadikota G. Resolving Salt-Induced Agglomeration of Laponite Suspensions Using X-ray Photon Correlation Spectroscopy and Molecular Dynamics Simulations. MATERIALS (BASEL, SWITZERLAND) 2022; 16:101. [PMID: 36614439 PMCID: PMC9820912 DOI: 10.3390/ma16010101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/04/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Linking the physics of the relaxation behavior of viscoelastic fluids as they form arrested gel states to the underlying chemical changes is essential for developing predictive controls on the properties of the suspensions. In this study, 3 wt.% laponite suspensions are studied as model systems to probe the influence of salt-induced relaxation behavior arising from the assembly of laponite nanodisks. X-ray Photon Correlation Spectroscopy (XPCS) measurements show that laponite suspensions prepared in the presence of 5 mM concentrations of CaCl2, MgCl2 and CsCl salts accelerate the formation of arrested gel states, with CaCl2 having a significant impact followed by CsCl and MgCl2 salts. The competing effects of ion size and charge on relaxation behavior are noted. For example, the relaxation times of laponite suspensions in the presence of Mg2+ ions are slower compared to Cs+ ions despite the higher charge, suggesting that cation size dominates in this scenario. The faster relaxation behavior of laponite suspensions in the presence of Ca2+ ions compared to Cs+ ions shows that a higher charge dominates the size of the ion. The trends in relaxation behavior are consistent with the cluster formation behavior of laponite suspensions and the electrostatic interactions predicted from MD simulations. Charge balance is achieved by the intercalation of the cations at the negatively charged surfaces of laponite suspensions. These studies show that the arrested gel state of laponite suspensions is accelerated in the presence of salts, with ion sizes and charges having a competing effect on relaxation behavior.
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Affiliation(s)
- Sohaib Mohammed
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Meishen Liu
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Qingteng Zhang
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Suresh Narayanan
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Fan Zhang
- Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Greeshma Gadikota
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
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3
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Leong YK, Liu P, Clode P, Liu J. Ageing behaviour spanning months of NaMt, hectorite and Laponite gels: Surface forces and microstructure – A comprehensive analysis. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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4
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Misra C, Ranganathan VT, Bandyopadhyay R. Influence of medium structure on the physicochemical properties of aging colloidal dispersions investigated using the synthetic clay LAPONITE®. SOFT MATTER 2021; 17:9387-9398. [PMID: 34605527 DOI: 10.1039/d1sm00987g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Physical aging in colloidal dispersions manifests as a reduction in kinetic freedom of the colloids. In aqueous dispersions of charged clay colloids, the role of interparticle electrostatic interactions in determining the aging dynamics has been evaluated extensively. Despite water being the dispersion medium, the influence of water structure on the physicochemical properties of aging clay dispersions has, however, not been considered before. In this work, we use LAPONITE®, a model hectorite clay mineral that acquires surface charges when dispersed in water, to study the relative contributions of dispersion medium structure and interparticle electrostatic interactions on the physicochemical properties of aging hectorite clay dispersions. The structure of the dispersion medium is modified either by incorporating dissociating/non-dissociating kosmotropic (structure-inducing) or chaotropic (structure-disrupting) molecules or by changing dispersion temperature. Photon correlation spectroscopy, rheological measurements and particle-scale imaging are employed to evaluate the physicochemical properties of the dispersions. Our experiments involving incorporation of external additives demonstrate a strong influence of dispersion medium structure on the dispersion properties when the interparticle electrostatic interactions are weak. We introduce a new temperature dependent measurement protocol, wherein the temperature of the medium is fixed before adding the clay particles, to manipulate the hydrogen bonds in the aqueous medium in the absence of external additives. Accelerated aging, observed upon raising the temperature regardless of the experimental thermal histories, is attributed to increased interparticle electrostatic interactions as in the room temperature experiments with ionic additives. Our study identifies that in the presence of weak interparticle electrostatic interactions, changes in the physicochemical properties of charged clay dispersions can be driven by manipulating hydrogen bond populations in aqueous medium.
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Affiliation(s)
- Chandeshwar Misra
- Soft Condensed Matter Group, Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560 080, India.
| | - Venketesh T Ranganathan
- 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.
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Labalette V, Praga A, Girard F, Meireles M, Hallez Y, Morris JF. Shear-induced glass-to-crystal transition in anisotropic clay-like suspensions. SOFT MATTER 2021; 17:3174-3190. [PMID: 33621310 DOI: 10.1039/d0sm02081h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A new numerical framework based on Stokesian dynamics is used to study a shear-induced glass-to-crystal transition in suspensions of clay-like anisotropically charged platelets. The structures obtained in quiescent conditions are in agreement with previous Monte Carlo results: a liquid phase at very short interaction range (high salt concentration), phase separation and a gel without large scale density fluctuations at intermediate interaction ranges, and glassy states at very large interaction ranges. When initially glassy suspensions are sheared, hydrodynamic torques first rotate platelets so they can reach a transient quasi-nematic disordered state. These orientational correlations permit to unlock translational degrees of freedom and the platelets then form strings aligned with the velocity direction and hexagonally packed in the gradient-vorticity plane. Under steady shear, platelet orientations are correlated but the system is not nematic. After flow cessation and relaxation in quiescent conditions, positional and orientational order are further improved as the platelet suspension experiences a transition to a nematic hexagonal crystal. Energy calculations and the existence of residual stress anisotropy after relaxation show that this final structure is not an equilibrium state but rather a new ordered, arrested state. The transient, nematic, disordered state induced by shear immediately after startup and unlocking translational degrees of freedom is thought to be an initial step that may be generic for other suspensions of strongly anisotropic colloids with important translation-orientation coupling induced by long-range interactions.
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Affiliation(s)
- Vincent Labalette
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France.
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6
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Sun Y, Pan D, Wei X, Xian D, Wang P, Hou J, Xu Z, Liu C, Wu W. Insight into the stability and correlated transport of kaolinite colloid: Effect of pH, electrolytes and humic substances. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 266:115189. [PMID: 32683164 DOI: 10.1016/j.envpol.2020.115189] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/03/2020] [Accepted: 07/04/2020] [Indexed: 06/11/2023]
Abstract
Environmental colloids play crucial roles in the transport of environmental pollutants in porous media by acting as pollutant carriers. In this work, the dispersion stability and correlated transport of kaolinite colloid were investigated as a function of solution pH, solution ionic strength, and concentration of humic acid (HA), the roles of kaolinite colloid in driving Eu(III) transport were discussed. The results showed that the dispersion of kaolinite colloid was favorable at alkaline and extremely acidic pH values, the trend of aggregation with varying pH was critically reversed at pH ∼3.2 due to the transformation of surface electrical properties. Cations with higher valence and mineral affinity showed a more significant contribution in inducing colloid aggregation, which was generally in accordance with the Schulze-Hardy rule and Hofmeister series. HA greatly increased the colloid stability by altering the surface electrostatic potential and steric effect. The Derjguin-Landau-Verwey-Overbeek (DLVO) model suggested that the electrostatic force between colloidal particles controlled the aggregation and destabilizing trend of colloid, and the theoretically calculated critical coagulation concentration was consistent with that determined from kinetic aggregation experiments. The roles of kaolinite colloid in driving Eu(III) transport varied under different conditions, and the transport behavior was highly correlated with the dispersion stability trend of colloid. These results can provide an enhanced understanding of the environmental fate of kaolinite colloid as well as commensal pollutants.
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Affiliation(s)
- Yalou Sun
- Radiochemistry Laboratory, School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, PR China
| | - Duoqiang Pan
- Radiochemistry Laboratory, School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, PR China.
| | - Xiaoyan Wei
- Radiochemistry Laboratory, School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, PR China
| | - Dongfan Xian
- Beijing National Laboratory for Molecular Sciences, Fundamental Science Laboratory on Radiochemistry and Radiation Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, PR China
| | - Peng Wang
- Radiochemistry Laboratory, School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, PR China
| | - Junjun Hou
- Radiochemistry Laboratory, School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, PR China
| | - Zhen Xu
- Radiochemistry Laboratory, School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, PR China
| | - Chunli Liu
- Beijing National Laboratory for Molecular Sciences, Fundamental Science Laboratory on Radiochemistry and Radiation Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, PR China
| | - Wangsuo Wu
- Radiochemistry Laboratory, School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, PR China
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7
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Shen X, Bourg IC. Molecular dynamics simulations of the colloidal interaction between smectite clay nanoparticles in liquid water. J Colloid Interface Sci 2020; 584:610-621. [PMID: 33223241 DOI: 10.1016/j.jcis.2020.10.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 08/20/2020] [Accepted: 10/08/2020] [Indexed: 10/23/2022]
Abstract
Colloidal interactions between clay nanoparticles have been studied extensively because of their strong influence on the hydrology and mechanics of many soils and sedimentary media. The predominant theory used to describe these interactions is the Derjaguin-Landau-Verwey-Overbeek (DLVO) model, a framework widely applied in colloidal and interfacial science that accurately predicts the interactions between charged surfaces across water films at distances greater than ~ 3 nm (i.e., ten water monolayers). Unfortunately, the DLVO model is inaccurate at the shorter interparticle distances that predominate in most subsurface environments. For example, it inherently cannot predict the existence of equilibrium states wherein clay particles adopt interparticle distances equal to the thickness of one, two, or three water monolayers. Molecular dynamics (MD) simulations have the potential to provide detailed information on the free energy of interaction between clay nanoparticles; however, they have only been used to examine clay swelling and aggregation at interparticle distances below 1 nm. We present the first MD simulation predictions of the free energy of interaction of smectite clay nanoparticles in the entire range of interparticle distances from the large interparticle distances where the DLVO model is accurate (>3 nm) to the short-range swelling states where non-DLVO interactions predominate (<1 nm). Our simulations examine a range of salinities (0.0 to 1.0 M NaCl) and counterion types (Na, K, Ca) and establish a detailed picture of the breakdown of the DLVO model. In particular, they confirm previous theoretical suggestions of the existence of a strong non-DLVO attraction with a range of ~ 3 nm arising from specific ion-clay Coulomb interactions in the electrical double layer.
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Affiliation(s)
- Xinyi Shen
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Ian C Bourg
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA; High Meadows Environmental Institute, Princeton University, Princeton, NJ 08544, USA
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8
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Stability Analysis of GMZ Bentonite Colloids: Aggregation Mechanism Transition and the Edge Effect in Strongly Alkaline Conditions. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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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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10
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Assembly of clay mineral platelets, tactoids, and aggregates: Effect of mineral structure and solution salinity. J Colloid Interface Sci 2020; 566:163-170. [DOI: 10.1016/j.jcis.2020.01.084] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/20/2020] [Accepted: 01/22/2020] [Indexed: 11/21/2022]
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11
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Jansson M, Skepö M. Polyelectrolyte-Nanoplatelet Complexation: Is It Possible to Predict the State Diagram? Int J Mol Sci 2019; 20:ijms20246217. [PMID: 31835497 PMCID: PMC6940988 DOI: 10.3390/ijms20246217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 11/12/2019] [Accepted: 12/04/2019] [Indexed: 12/02/2022] Open
Abstract
The addition of polyelectrolytes (PEs) to suspensions of charged colloids, such as nanoplatelets (NPs), is of great interest due to their specific feature of being either a stabilizing or a destabilizing agent. Here, the complexation between a PE and oppositely charged NPs is studied utilizing coarse-grained molecular dynamics simulations based on the continuum model. The complex formation is evaluated with respect to the stoichiometric charge-ratio within the system, as well as by the alternation of the chain properties. It is found that the formed complexes can possess either an extended or a compact shape. Moreover, it is observed that the chain can become overcharged by the oppositely charged NPs. With an increase in chain length, or a decrease in chain flexibility, the complex obtains a more extended shape, where the NPs are less tightly bound to the PE. The latter is also true when reducing the total charge of the chain by varying the linear charge density, whereas in this case, the chain contracts. With our coarse-grained model and molecular dynamics simulations, we are able to predict the composition and the shape of the formed complex and how it is affected by the characteristics of the chain. The take-home message is that the complexation between PEs and NPs results in a versatile and rich state diagram, which indeed is difficult to predict, and dependent on the properties of the chain and the model used. Thus, we propose that the present model can be a useful tool to achieve an understanding of the PE-NPs complexation, a system commonly used in industrial and in technological processes.
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Affiliation(s)
- Maria Jansson
- Theoretical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
- Correspondence: (M.J.); (M.S.)
| | - Marie Skepö
- Theoretical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
- LINXS—Lund Institute of Advanced Neutron and X-ray Science, Scheelevägen 19, SE-223 70 Lund, Sweden
- Correspondence: (M.J.); (M.S.)
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12
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A hybrid nanocomposite of poly(styrene-methyl methacrylate- acrylic acid) /clay as a novel rheology-improvement additive for drilling fluids. JOURNAL OF POLYMER RESEARCH 2019. [DOI: 10.1007/s10965-019-1696-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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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: 46] [Impact Index Per Article: 7.7] [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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14
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Leong YK, Du M, Au PI, Clode P, Liu J. Microstructure of Sodium Montmorillonite Gels with Long Aging Time Scale. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:9673-9682. [PMID: 30053778 DOI: 10.1021/acs.langmuir.8b00213] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Purified sodium montmorillonite (SWy-2) gels of a few percent solids displayed pronounced time-dependent rheological or aging behavior with a long time scale. The aging behavior was characterized by an increasing yield stress with rest time. This increase continued even after a week of rest. An open sponge-like cellular microstructure of the aged gels was captured by cryo-SEM with samples prepared at high pressure. The size of the openings of the cellular structure is small, generally less than 1 μm formed by thin flexible platelet with curling edges. This structure was formed by strong attractive and repulsive forces. The rapid yield stress increase in the early stage of aging is due to rapid bond formation occurring between network platelets and free individual platelet, isolated aggregates, and platelet particles in network with free edges. Over time, all platelets are bonded in the network. During aging, the platelets in the structure would have to adjust continually in response to a net force acting on it by its neighbors. The high concentration of platelets responding to this force imbalance is the cause of the long aging time scale. The operation of the attractive and repulsive forces, and the shape and charge properties of the platelets are responsible for the cellular structure being built. At complete structural recovery, the structure should attain the state of lowest free energy. The repulsive force regulates the development of the microstructure. The aging data of the 3.3 wt % gel were fitted by different aging models.
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Affiliation(s)
| | | | - Pek-Ing Au
- Department of Chemical Engineering , Curtin University , Miri , Sarawak , Malaysia , 98009
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15
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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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16
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Bourg IC, Ajo-Franklin JB. Clay, Water, and Salt: Controls on the Permeability of Fine-Grained Sedimentary Rocks. Acc Chem Res 2017; 50:2067-2074. [PMID: 28862427 DOI: 10.1021/acs.accounts.7b00261] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The ability to predict the permeability of fine-grained soils, sediments, and sedimentary rocks is a fundamental challenge in the geosciences with potentially transformative implications in subsurface hydrology. In particular, fine-grained sedimentary rocks (shale, mudstone) constitute about two-thirds of the sedimentary rock mass and play important roles in three energy technologies: petroleum geology, geologic carbon sequestration, and radioactive waste management. The problem is a challenging one that requires understanding the properties of complex natural porous media on several length scales. One inherent length scale, referred to hereafter as the mesoscale, is associated with the assemblages of large grains of quartz, feldspar, and carbonates over distances of tens of micrometers. Its importance is highlighted by the existence of a threshold in the core scale mechanical properties and regional scale energy uses of shale formations at a clay content Xclay ≈ 1/3, as predicted by an ideal packing model where a fine-grained clay matrix fills the gaps between the larger grains. A second important length scale, referred to hereafter as the nanoscale, is associated with the aggregation and swelling of clay particles (in particular, smectite clay minerals) over distances of tens of nanometers. Mesoscale phenomena that influence permeability are primarily mechanical and include, for example, the ability of contacts between large grains to prevent the compaction of the clay matrix. Nanoscale phenomena that influence permeability tend to be chemomechanical in nature, because they involve strong impacts of aqueous chemistry on clay swelling. The second length scale remains much less well characterized than the first, because of the inherent challenges associated with the study of strongly coupled nanoscale phenomena. Advanced models of the nanoscale properties of fine-grained media rely predominantly on the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, a mean field theory of colloidal interactions that accurately predicts clay swelling in a narrow range of conditions (low salinity, low compaction, Na+ counterion). An important feature of clay swelling that is not predicted by these models is the coexistence, in most conditions of aqueous chemistry and dry bulk density, of two types of pores between parallel smectite particles: mesopores with a pore width of >3 nm that are controlled by long-range interactions (the osmotic swelling regime) and nanopores with a pore width <1 nm that are controlled by short-range interactions (the crystalline swelling regime). Nanogeochemical characterization and simulation techniques, including coarse-grained and all-atom molecular dynamics simulations, hold significant promise for the development of advanced constitutive relations that predict this coexistence and its dependence on aqueous chemistry.
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Affiliation(s)
- Ian C. Bourg
- Princeton University, Department of Civil and Environmental Engineering (CEE) and Princeton Environmental Institute (PEI), Princeton New Jersey 08544, United States
| | - Jonathan B. Ajo-Franklin
- Lawrence Berkeley National Laboratory, Energy Geoscience Division, Berkeley California 94720, United States
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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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Jatav S, Joshi YM. Phase Behavior of Aqueous Suspension of Laponite: New Insights with Microscopic Evidence. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:2370-2377. [PMID: 28209059 DOI: 10.1021/acs.langmuir.7b00151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Investigating microstructure of suspensions with particles having anisotropic shape that share complex interactions is a challenging task leading to competing claims. This work investigates phase behavior of one such system: aqueous Laponite suspension, which is highly contested in the literature, using rheological and microscopic tools. Remarkably, we observe that over a broad range of Laponite (1.4 to 4 wt %) and salt concentrations (0 to 7 mM), the system overwhelmingly demonstrates all the rheological characteristics of the sol-gel transition leading to a percolated network. Analysis of the rheological response leads to fractal dimension that primarily depends on the Laponite concentration. We also obtain the activation energy for gelation, which is observed to decrease with increase in Laponite as well as salt concentration. Significantly, the cryo-TEM images of the postgel state clearly show the presence of a percolated network formed by interparticle bonds. The present work therefore conclusively establishes the system to be in an attractive gel state resolving a long-standing debate in the literature.
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Affiliation(s)
- Shweta Jatav
- Department of Chemical Engineering, Indian Institute of Technology , Kanpur 208016, India
| | - Yogesh M Joshi
- Department of Chemical Engineering, Indian Institute of Technology , Kanpur 208016, India
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20
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Jain M, Matsumura K. Thixotropic injectable hydrogel using a polyampholyte and nanosilicate prepared directly after cryopreservation. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 69:1273-81. [DOI: 10.1016/j.msec.2016.08.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/27/2016] [Accepted: 08/12/2016] [Indexed: 11/30/2022]
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21
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Mortimer GM, Jack KS, Musumeci AW, Martin DJ, Minchin RF. Stable non-covalent labeling of layered silicate nanoparticles for biological imaging. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 61:674-80. [PMID: 26838896 DOI: 10.1016/j.msec.2015.12.047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 11/07/2015] [Accepted: 12/15/2015] [Indexed: 12/26/2022]
Abstract
Layered silicate nanoparticles (LSN) are widely used in industrial applications and consumer products. They also have potential benefits in biomedical applications such as implantable devices and for drug delivery. To study how nanomaterials interact with cells and tissues, techniques to track and quantify their movement through different biological compartments are essential. While radiolabels can be very sensitive, particularly for in vivo studies, fluorescent labeling has been preferred in recent years because of the array of methods available to image and quantify fluorescent nanoparticles. However, labeling can be problematic, especially if it alters the physical properties of the nanomaterial. Herein is described a novel non-covalent labeling technique for LSN using readily available fluorescent dimeric cyanine dyes without the need to use excess amounts of dye to achieve labeling, or the need for removal of unbound dye. The approach utilizes the cationic binding properties of layered silicate clays and the multiple quaternary nitrogens associated with the dyes. Preparation of YOYO-1 labeled LSN with optimal dispersion in aqueous media is presented. The utilization of the labeled particles is then demonstrated in cell binding and uptake studies using flow cytometry and confocal microscopy. The labeled LSN are highly fluorescent, stable and exhibit identical physical properties with respect to the unlabeled nanoparticles. The general approach described here is applicable to other cyanine dyes and may be utilized more widely for labeling nanoparticles that comprise a crystalline plate structure with a high binding capacity.
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Affiliation(s)
- Gysell M Mortimer
- School of Biomedical Sciences, University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Kevin S Jack
- Centre for Microscopy and Microanalysis, University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Anthony W Musumeci
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Darren J Martin
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Rodney F Minchin
- School of Biomedical Sciences, University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
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22
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Ali S, Bandyopadhyay R. Effect of electrolytes on the microstructure and yielding of aqueous dispersions of colloidal clay. SOFT MATTER 2016; 12:414-421. [PMID: 26477340 DOI: 10.1039/c5sm01700a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Na-montmorillonite is a natural clay mineral and is available in abundance in nature. The aqueous dispersions of charged and anisotropic platelets of this mineral exhibit non-ergodic kinetically arrested states ranging from soft glassy phases dominated by interparticle repulsions to colloidal gels stabilized by salt induced attractive interactions. When the salt concentration in the dispersing medium is varied systematically, viscoelasticity and yield stress of the dispersion show non-monotonic behavior at a critical salt concentration, thus signifying a morphological change in the dispersion microstructures. We directly visualize the microscopic structures of these kinetically arrested phases using cryogenic scanning electron microscopy. We observe the existence of honeycomb-like network morphologies for a wide range of salt concentrations. The transition of the gel morphology, dominated by overlapping coin (OC) and house of cards (HoC) associations of clay particles at low salt concentrations to a new network structure dominated by face-face coagulation of platelets, is observed across the critical salt concentration. We further assess the stability of these gels under gravity using electroacoustics. This study, performed for concentrated clay dispersions for a wide concentration range of externally added salt, is useful in our understanding of many geophysical phenomena that involve the salt induced aggregation of natural clay minerals.
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Affiliation(s)
- Samim Ali
- Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560080, India.
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23
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Surface chemistry–microstructure–rheology of high and low crystallinity KGa-1b and KGa-2 kaolinite suspensions. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2015.08.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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24
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25
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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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26
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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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27
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Ebrahimi D, Whittle AJ, Pellenq RJM. Mesoscale properties of clay aggregates from potential of mean force representation of interactions between nanoplatelets. J Chem Phys 2014. [DOI: 10.1063/1.4870932] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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28
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Delhorme M, Jönsson B, Labbez C. Gel, glass and nematic states of plate-like particle suspensions: charge anisotropy and size effects. RSC Adv 2014. [DOI: 10.1039/c4ra05555a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The influence of the charge anisotropy and platelet size on the formation of gel and glass states and nematic phases in suspensions of plate-like particles is investigated using Monte Carlo simulations in the canonical ensemble.
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Affiliation(s)
- Maxime Delhorme
- Laboratoire Interdisciplinaire Carnot de Bourgogne
- UMR 6303 CNRS
- Université de Bourgogne
- F-21078 Dijon, France
- Theoretical Chemistry
| | - Bo Jönsson
- Theoretical Chemistry
- Lund University
- Chemical Center
- S-221 00 Lund, Sweden
| | - Christophe Labbez
- Laboratoire Interdisciplinaire Carnot de Bourgogne
- UMR 6303 CNRS
- Université de Bourgogne
- F-21078 Dijon, France
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29
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Ghadiri M, Chrzanowski W, Lee WH, Rohanizadeh R. Layered silicate clay functionalized with amino acids: wound healing application. RSC Adv 2014. [DOI: 10.1039/c4ra05216a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Laponite holds amino acid between its interlayer spaces and releases it in contact with wound fluid through ionic exchange process.
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Affiliation(s)
- M. Ghadiri
- Faculty of Pharmacy
- University of Sydney
- Sydney, Australia
| | - W. Chrzanowski
- Faculty of Pharmacy
- University of Sydney
- Sydney, Australia
| | - W. H. Lee
- Respiratory Technology
- Woolcock Institute of Medical Research
- NSW 2006, Australia
| | - R. Rohanizadeh
- Faculty of Pharmacy
- University of Sydney
- Sydney, Australia
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30
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Jiang C, Huang H, Ma C, He T, Zhang F. Influence of particle size and tunable interactions on isotropic-nematic transition of block copolymer single crystal platelet suspensions. J Colloid Interface Sci 2013; 411:53-60. [PMID: 24112840 DOI: 10.1016/j.jcis.2013.08.054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/22/2013] [Accepted: 08/28/2013] [Indexed: 11/17/2022]
Abstract
We have studied the influence of the particle size and the tunable lateral interactions on the isotropic-nematic (I-N) phase transition of a plate-like colloidal system. The particles are single crystals of a block copolymer PS-b-PLLA (BCSC) prepared using a self-seeding procedure. These lozenge shape crystals have a uniform thickness and a narrowly distributed lateral size. The equilibrium phase behavior and I-N phase transition have been characterized using crossed polarizers at the room temperature. A nematic phase exists for all systems with size ranging from 700 to 4000 nm. For smaller crystals (<1200 nm), the I-N phase transition follows a process of slow sedimentation and subsequent macroscopic phase separation, resulting in a highly oriented nematic phase with a sharp I-N interface. For larger crystals (≥1200 nm), the I-N phase transition follows a process of nucleation and subsequent sedimentation, resulting in a random orientation of crystals in the nematic phase and a rough I-N interface. The I-N transition occurs at a very low volume fraction (<0.2%) for all systems, which is at least one order of magnitude lower than the theoretical prediction (2-7%). However, addition of a small amount of ethanol into the solution, the I-N transition can be significantly suppressed. These results demonstrate the existence of a lateral attraction between crystals, which is due to the polar attraction between the uncovered PLLA crystalline domains. Polar ethanol molecules can adsorb to the PLLA crystalline surface and screen the attraction. The attraction exhibits highly orientation-dependent. To further demonstrate this highly directional attraction, we have prepared two composite single crystal suspensions with PLLA homopolymer, which have a much wider open angle for the polar attraction. Indeed, the resulting liquid crystalline phases show much less horizontal ordering.
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Affiliation(s)
- Chunbo Jiang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China; University of Chinese Academy of Sciences, Beijing 10039, PR China.
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31
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Segad M. Microstructure determination of IQ-WB clays: a direct procedure by small-angle X-ray scattering. J Appl Crystallogr 2013. [DOI: 10.1107/s0021889813020931] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
An accurate characterization of the microstructure of raw and pure homoionic clays from Wadi Bashira in Iraq (IQ-WB) has been carried out experimentally, using small-angle X-ray scattering (SAXS) and dynamic light scattering. The structures of lamellar IQ-WB dispersions were identified by these techniques and by complementary free swelling and dialysis experiments. SAXS measurements were used to resolve the characteristic distance,hs, between individual platelets in Na IQ-WB and between platelets inside tactoids formed in Ca clays. The tactoids in raw and Ca IQ-WB have well formed lamellar structures wherehs= 1.9 nm. The average lateral size, 〈D〉, of a platelet is determined to be a few hundred nanometres. Analysis of the SAXS peaks, based on the Scherrer relation, revealed a small difference in the average number of platelets per tactoid, 〈N〉 = 6–9, depending on platelet size and the concentrations of divalent counter-ions. It was also found that the average tactoid size can be estimated from an empirical relation as follows: 〈N〉 ≃ δ + α〈D〉, where δ is a constant and α the slope.
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32
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Au PI, Leong YK. Rheological and zeta potential behaviour of kaolin and bentonite composite slurries. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2013.06.039] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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33
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Trefalt G, Szilagyi I, Borkovec M. Poisson-Boltzmann description of interaction forces and aggregation rates involving charged colloidal particles in asymmetric electrolytes. J Colloid Interface Sci 2013; 406:111-20. [PMID: 23827478 DOI: 10.1016/j.jcis.2013.05.071] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/08/2013] [Accepted: 05/25/2013] [Indexed: 11/17/2022]
Abstract
Forces and aggregation rates involving spherical particles are studied numerically within the theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO) for asymmetric and mixed electrolytes. Thereby, the double layer interactions are treated at the Debye-Hückel (DH) and Poisson-Boltzmann (PB) levels. The DH model is applicable for weakly charged systems, and effects of ion valence enter only implicitly through the ionic strength. The PB model is necessary for more highly charged systems, and depends on the actual ionic composition. One finds that forces in asymmetric electrolytes at fixed ionic strength weaken when the valence of the counterions is increased or when the valence of the coions is decreased. In symmetric electrolytes, the effect of counterions is more important than the one of the coions. For weakly charged systems, the critical coagulation concentration (CCC) decreases with the square of the valence in symmetric electrolytes, while this decrease is weaker in asymmetric ones. With increasing charge density, the dependence of the CCC on the valence becomes stronger, but the classical Schulze-Hardy decrease with the sixths power of the valence is only recovered for unrealistically high charge densities. Mixtures of electrolytes are treated within the same framework, and one observes that already small amounts of multivalent ions affect the system considerably. An empirical mixing rule is proposed to describe the calculated CCCs.
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Affiliation(s)
- Gregor Trefalt
- Department of Inorganic and Analytical Chemistry, University of Geneva, Geneva, Switzerland
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34
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Michot LJ, Bihannic I, Thomas F, Lartiges BS, Waldvogel Y, Caillet C, Thieme J, Funari SS, Levitz P. Coagulation of Na-montmorillonite by inorganic cations at neutral pH. A combined transmission X-ray microscopy, small angle and wide angle X-ray scattering study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:3500-3510. [PMID: 23421550 DOI: 10.1021/la400245n] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The coagulation of sodium montmorillonite by inorganic salts (NaNO3, Ca(NO3)2 and La(NO3)3) was studied by combining classical turbidity measurements with wide-angle-X-ray scattering (WAXS), small-angle-X-ray scattering (SAXS), and transmission X-ray microscopy (TXM). Using size-selected samples, such a combination, associated with an original quantitative treatment of TXM images, provides a true multiscale investigation of the formed structures in a spatial range extending from a few ångstroms to a few micrometers. We then show that, at neutral pH and starting with fully Na-exchanged samples, coagulation proceeds via the formation of stacks of particles with a slight mismatch between layers. These stacks arrange themselves into larger porous anisotropic particles, the porosity of which depends on the valence of the cation used for coagulation experiments. Face-face coagulation is clearly dominant under those conditions, and no evidence for significant face-edge coagulation was found. These structures appear to arrange as larger clusters, the organization of which should control the mechanical properties of the flocs.
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Affiliation(s)
- Laurent J Michot
- Laboratoire Interdisciplinaire des Environnements Continentaux, UMR 7360 CNRS-Université de Lorraine, Vandœuvre, France.
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35
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Lützenkirchen J, Preočanin T, Bauer A, Metz V, Sjöberg S. Net surface proton excess of smectites obtained from a combination of potentiometric acid–base, mass and electrolyte titrations. Colloids Surf A Physicochem Eng Asp 2012. [DOI: 10.1016/j.colsurfa.2012.06.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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36
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Delhorme M, Labbez C, Jönsson B. Liquid Crystal Phases in Suspensions of Charged Plate-Like Particles. J Phys Chem Lett 2012; 3:1315-20. [PMID: 26286776 DOI: 10.1021/jz300380n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Anisotropic interactions in colloidal suspensions have recently emerged as a route for the design of new soft materials. Nonisotropic particles can form nematic, smectic, hexatic, and columnar liquid crystals. Although the formation of these phases is well rationalized when excluded volume is solely at play, the role of electrostatic interactions still remains unclear and even less so when particles present a charge heterogeneity, for example, clays. Here, we use Monte Carlo simulations of concentrated suspensions of charged disk-like particles to reveal the role of Coulomb interactions and charge anisotropy underlying liquid crystal formation and structures. We observe a vast zoo of exotic structures, going from hexatic to columnar phases, which are shown to be controlled by the charge anisotropy. The particle volume fraction at which these phases start to form is found to decrease with increasing Coulomb interactions and charge anisotropy, which suggests a route to tune the structure of aqueous liquid crystals.
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Affiliation(s)
- Maxime Delhorme
- †Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Université de Bourgogne, 21078 Dijon Cedex, France
| | - Christophe Labbez
- †Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Université de Bourgogne, 21078 Dijon Cedex, France
| | - Bo Jönsson
- ‡Department of Theoretical Chemistry, Chemical Center, POB 124, S-221 00 Lund, Sweden
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37
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Zhang J, Li L, Wang J, Sun H, Xu J, Sun D. Double inversion of emulsions induced by salt concentration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:6769-6775. [PMID: 22475400 DOI: 10.1021/la300695v] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The effects of salt on emulsions containing sorbitan oleate (Span 80) and Laponite particles were investigated. Surprisingly, a novel double phase inversion was induced by simply changing the salt concentration. At fixed concentration of Laponite particles in the aqueous phase and surfactant in paraffin oil, emulsions are oil in water (o/w) when the concentration of NaCl is lower than 5 mM. Emulsions of water in oil (w/o) are obtained when the NaCl concentration is between 5 and 20 mM. Then the emulsions invert to o/w when the salt concentration is higher than 50 mM. In this process, different emulsifiers dominate the composition of the interfacial layer, and the emulsion type is correspondingly controlled. When the salt concentration is low in the aqueous dispersion of Laponite, the particles are discrete and can move to the interface freely. Therefore, the emulsions are stabilized by particles and surfactant, and the type is o/w as particles are in domination. At intermediate salt concentrations, the aqueous dispersions of Laponite are gel-like, the viscosity is high, and the transition of the particles from the aqueous phase to the interface is inhibited. The emulsions are stabilized mainly by lipophilic surfactant, and w/o emulsions are obtained. For high salt concentration, flocculation occurs and the viscosity of the dispersion is reduced; thus, the adsorption of particles is promoted and the type of emulsions inverts to o/w. Laser-induced fluorescent confocal micrographs and cryo transmission electron microscopy clearly confirm the adsorption of Laponite particles on the surface of o/w emulsion droplets, whereas the accumulation of particles at the w/o emulsion droplet surfaces was not observed. This mechanism is also supported by the results of rheology and interfacial tension measurements.
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Affiliation(s)
- Jingchun Zhang
- Key Laboratory for Colloid and Interface Chemistry of the Ministry of Education, Shandong University, Jinan, Shandong 250100, People's Republic of China
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38
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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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39
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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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Jönsson B, Persello J, Li J, Cabane B. Equation of state of colloidal dispersions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:6606-14. [PMID: 21557550 DOI: 10.1021/la2001392] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We present a comparison of experimentally and theoretically determined osmotic pressures for various colloidal dispersions. Experimental data is collected from several different silica and polystyrene dispersions. The theoretical pressure determinations are based on the primitive model combined with the cell model, and the physical quantities are calculated exactly using Monte Carlo simulations in the canonical and grand canonical ensemble. The input to the simulations in terms of colloidal particle size, surface charge density, and so forth are taken directly from experiments, and the approach does not contain any adjustable parameters. The agreement between theory and experiment is very good without any fitting parameters, showing that the simplifications behind the primitive model and the cell model are physically sound. The results reveal a surprising correspondence between the equations of state in spherical and planar geometries, indicating that the particle shape is of secondary importance in dispersions dominated by repulsive interactions. For one of the silica dispersions, we have also investigated how various monovalent counterions influence the swelling properties. Within experimental error, we are unable to detect any ion specificity, which is further support for the theoretical models used.
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Affiliation(s)
- Bo Jönsson
- Theoretical Chemistry, Chemical Center, POB 124, S-221 00 Lund, Sweden
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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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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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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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Kakiage M, Ando S. Effects of dispersion and arrangement of clay on thermal diffusivity of polyimide-clay nanocomposite film. J Appl Polym Sci 2010. [DOI: 10.1002/app.33034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Shankar P, Teo J, Leong YK, Fourie A, Fahey M. Adsorbed phosphate additives for interrogating the nature of interparticles forces in kaolin clay slurries via rheological yield stress. ADV POWDER TECHNOL 2010. [DOI: 10.1016/j.apt.2010.02.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Porion P, Faugère AM, Michot LJ, Paineau E, Delville A. Orientational microdynamics and magnetic-field-induced ordering of clay platelets detected by 2H NMR spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:7035-7044. [PMID: 20047274 DOI: 10.1021/la904298d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The orientation of montmorillonite clays induced by a static magnetic field is quantified by using (2)H NMR spectroscopy. Indeed, the residual quadrupolar splitting of the (2)H resonance line measured for heavy water is a direct consequence of the specific orientation of the clay platelets in the static magnetic field. In the dilute regime, this residual splitting increases linearly with clay concentration, which confirms that the clay/clay electrostatic repulsions remain negligible by comparison with the diamagnetic coupling of these anisotropic platelets. At higher concentration, the electrostatic repulsion between clay particles markedly enhances the detected splitting. Such enhancement is well predicted by numerical simulations. By varying the size of the clay platelets and the strength of the static magnetic field, it is possible to evaluate the order of magnitude of the diamagnetic susceptibility of these anisotropic colloids.
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Affiliation(s)
- Patrice Porion
- Centre de Recherche sur la Matière Divisée, CNRS-Université d'Orléans, UMR6619, 45071 Orléans Cedex 02, France.
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Mourad MCD, Byelov DV, Petukhov AV, Matthijs de Winter DA, Verkleij AJ, Lekkerkerker HNW. Sol-gel transitions and liquid crystal phase transitions in concentrated aqueous suspensions of colloidal gibbsite platelets. J Phys Chem B 2010; 113:11604-13. [PMID: 19655775 DOI: 10.1021/jp903783b] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper, we present a comprehensive study of the sol-gel transitions and liquid crystal phase transitions in aqueous suspensions of positively charged colloidal gibbsite platelets at pH 4-5 over a wide range of particle concentrations (50-600 g/L) and salt concentrations (10(-4)-10(-1) M NaCl). A detailed sol-gel diagram was established by oscillatory rheological experiments. These demonstrate the presence of kinetically arrested states both at high and at low salt concentrations, enclosing a sol region. Birefringence and iridescence show that in the sol state nematic and hexagonal columnar liquid crystal phases are formed. The gel and liquid crystal structures are studied in further detail using small-angle X-ray scattering (SAXS) and cryo-focused ion beam/scanning electron microscopy (cryo-FIB-SEM). The gel formed at high salt concentration shows signatures of a sponge-like structure and does not display birefringence. In the sol region, by lowering the salt concentration and/or increasing the gibbsite concentration, the nematic phase gradually transforms from the discotic nematic (ND) into the columnar nematic (NC) with much stronger side-to-side interparticle correlations. Subsequently, this NC structure can be either transformed into the hexagonal columnar phase or arrested into a birefringent repulsive gel state with NC structure.
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Affiliation(s)
- Maurice C D Mourad
- van 't Hoff Laboratory for Physical and Colloid Chemistry, Faculty of Sciences, Utrecht University, P.O. Box 80.056, 3508 TB Utrecht, The Netherlands.
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