1
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Kale S, Lederer A, Oettel M, Schöpe HJ. Approaching the hard sphere limit in colloids suitable for confocal microscopy - the end of a decade lasting quest. SOFT MATTER 2023; 19:2146-2157. [PMID: 36880153 DOI: 10.1039/d2sm01427k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
PMMA-PHSA particles serve as the hard sphere model system since the 1980s. We investigate the fluid structure of fluorescent ones in three different solvents by laser scanning confocal microscopy: a decalin-tetrachloroethylene (TCE)-mixture and a decalin-cyclohexylbromide (CHB)-mixture with and without tetrabutylammoniumbromide (TBAB). The experimental 3D radial distribution functions are modeled by analytical theory and computer simulations taking polydispersity and the experimental position uncertainty into account. The quantitative comparison between experiment and simulation/theory establishes hard sphere like behavior for particles in decalin-TCE for a wide range of particle packing fractions. To the best of our knowledge, we present the first experimental dataset of a fluid structure that agrees convincingly with Percus-Yevick over a wide concentration range. Furthermore, charged sphere behavior is confirmed both for the decalin-CHB and the decalin-CHB-TBAB solvents, and it is demonstrated that a finite particle concentration reduces screening in the decalin-CHB-TBAB system compared to the bulk solvent.
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Affiliation(s)
- Sahana Kale
- Institute for Applied Physics, Eberhard Karls University Tubingen, Auf der Morgenstelle 10, 72076 Tubingen, Germany.
| | - Achim Lederer
- Retsch Technology GmbH, Retsch-Allee 1-5, 42781 Haan, Germany
| | - Martin Oettel
- Institute for Applied Physics, Eberhard Karls University Tubingen, Auf der Morgenstelle 10, 72076 Tubingen, Germany.
| | - Hans Joachim Schöpe
- Institute for Applied Physics, Eberhard Karls University Tubingen, Auf der Morgenstelle 10, 72076 Tubingen, Germany.
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2
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Chen Y, Zhang Q, Ramakrishnan S, Leheny RL. Memory in aging colloidal gels with time-varying attraction. J Chem Phys 2023; 158:024906. [PMID: 36641382 DOI: 10.1063/5.0126432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We report a combined rheology, x-ray photon correlation spectroscopy, and modeling study of gel formation and aging in suspensions of nanocolloidal spheres with volume fractions of 0.20 and 0.43 and with a short-range attraction whose strength is tuned by changing temperature. Following a quench from high temperature, where the colloids are essentially hard spheres, to a temperature below the gel point, the suspensions form gels that undergo aging characterized by a steadily increasing elastic shear modulus and slowing, increasingly constrained microscopic dynamics. The aging proceeds at a faster rate for stronger attraction strength. When the attraction strength is suddenly lowered during aging, the gel properties evolve non-monotonically in a manner resembling the Kovacs effect in glasses, in which the modulus decreases and the microscopic dynamics become less constrained for a period before more conventional aging resumes. Eventually, the properties of the gel following the decrease in attraction strength converge to those of a gel that has undergone aging at the lower attraction strength throughout. The time scale of this convergence increases as a power law with the age at which the attraction strength is decreased and decreases exponentially with the magnitude of the change in attraction. A model for gel aging in which particles attach and detach from the gel at rates that depend on their contact number reproduces these trends and reveals that the non-monotonic behavior results from the dispersion in the rates that the populations of particles with different contact number adjust to the new attraction strength.
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Affiliation(s)
- Yihao Chen
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Qingteng Zhang
- X-Ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Subramanian Ramakrishnan
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, Florida 32310, USA
| | - Robert L Leheny
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
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3
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Chambon L, Das M, Vasilaki E, Petekidis G, Vamvakaki M. Colloidal Rod-Like Particles with Temperature-Driven Tunable Interactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13674-13685. [PMID: 36263911 DOI: 10.1021/acs.langmuir.2c01716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Temperature-sensitive rod-like colloidal particles were synthesized by grafting a temperature-responsive polymer, poly(2-(dimethylamino)ethyl methacrylate) (PDMA), on the surface of high aspect ratio silica rods by surface-initiated atom transfer radical polymerization. The stability of the grafted polymer on the surface of the particles in aqueous solutions was found to deteriorate with time, leading to a gradual decrease of the polymer content of the hybrid colloids, which was attributed to the mechanically activated hydrolysis of the labile bonds at the polymer-silica interface. The polymer degrafting was significantly suppressed by first growing a hydrophobic poly(methyl methacrylate) block onto the particle surface to act as a barrier layer for the penetration of water molecules at the polymer-particle interface, followed by chain-extension with the hydrophilic PDMA chains. Dynamic light scattering, microscopy, and rheological measurements revealed that the PDMA block conferred a temperature-responsive behavior to the rod-like particles, which formed aggregates at temperatures above the lower critical solution temperature (LCST) of the polymer. However, in contrast to their spherical counterparts, the polymer-grafted rod-like particles did not exhibit complete thermo-reversibility upon lowering the solution temperature below the LCST of PDMA, which was reflected by different values of the diffusion coefficient for the heating and cooling cycles, indicating an irreversible rod particle aggregation upon increasing the temperature.
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Affiliation(s)
- Lucille Chambon
- Department of Materials Science and Technology, University of Crete, 700 13Heraklion, Crete, Greece
- Institute of Electronic Structure and Laser, Foundation for Research and Technology─Hellas, 700 13Heraklion, Crete, Greece
| | - Mohan Das
- Department of Materials Science and Technology, University of Crete, 700 13Heraklion, Crete, Greece
- Institute of Electronic Structure and Laser, Foundation for Research and Technology─Hellas, 700 13Heraklion, Crete, Greece
| | - Evangelia Vasilaki
- Department of Materials Science and Technology, University of Crete, 700 13Heraklion, Crete, Greece
- Institute of Electronic Structure and Laser, Foundation for Research and Technology─Hellas, 700 13Heraklion, Crete, Greece
| | - George Petekidis
- Department of Materials Science and Technology, University of Crete, 700 13Heraklion, Crete, Greece
- Institute of Electronic Structure and Laser, Foundation for Research and Technology─Hellas, 700 13Heraklion, Crete, Greece
| | - Maria Vamvakaki
- Department of Materials Science and Technology, University of Crete, 700 13Heraklion, Crete, Greece
- Institute of Electronic Structure and Laser, Foundation for Research and Technology─Hellas, 700 13Heraklion, Crete, Greece
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4
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Suman K, Wagner NJ. Anomalous rheological aging of a model thermoreversible colloidal gel following a thermal quench. J Chem Phys 2022; 157:024901. [DOI: 10.1063/5.0094237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the aging behavior in a well-studied model system comprised of a colloidal suspension of thermoreversible adhesive hard spheres (AHS) but thermally quenched below the gel transition to much larger depths than previously studied. The aging behavior in the model AHS system is monitored by small amplitude oscillatory shear rheology measurements conducted while rapidly quenching from liquid state at 40{degree sign}C to a temperature below the gel temperature and new, anomalous aging behaviors are observed. Shallow quenches lead to monotonic development of the elastic modulus with time consistent with prior reports for the development of a homogeneous gel (Gordon et al., Journal of Rheology 2017). However, for deeper quenches, a unique and new phenomenon is reported - namely after an initial rise in the modulus, a reproducible drop in modulus is observed, followed by a plateau in modulus value. This drop can be gradual or sudden, and the extent of the drop, both depends on quench depth. After this drop in modulus, AHS gel evolves toward a quench-path independent state over the experimental timescale. These effects of the extent of quenching on aging behavior is hypothesized to be a consequence of quenching into different underlying thermodynamic states of colloidal gels and the possible influence of the adhesive glass dynamical arrest for the deepest quenches. The research connects homogeneous gelation with heterogeneous gel formation due to phase separation and shows that the extent of quench can be used as an independent parameter to govern the rheological response of the arrested gel.
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Affiliation(s)
- Khushboo Suman
- Department of Chemical and Biomolecular Engineering, University of Delaware, United States of America
| | - Norman J Wagner
- Chemical & Bimolecular Engineering Department, University of Delaware Department of Chemical and Biomolecular Engineering, United States of America
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5
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Arora P, Sood AK, Ganapathy R. Motile Topological Defects Hinder Dynamical Arrest in Dense Liquids of Active Ellipsoids. PHYSICAL REVIEW LETTERS 2022; 128:178002. [PMID: 35570456 DOI: 10.1103/physrevlett.128.178002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/22/2022] [Indexed: 06/15/2023]
Abstract
Recent numerical studies have identified the persistence time of active motion as a critical parameter governing glassy dynamics in dense active matter. Here we studied dynamics in liquids of granular active ellipsoids with tunable persistence and velocity. We show that increasing the persistence time at moderate supercooling is equivalent to increasing the strength of attraction in equilibrium liquids and results in reentrant dynamics not just in the translational degrees of freedom, as anticipated, but also in the orientational ones. However, at high densities, motile topological defects, unique to active liquids of elongated particles, hindered dynamical arrest. Most remarkably, for the highest activity, we observed intermittent dynamics due to the jamming-unjamming of these defects for the first time.
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Affiliation(s)
- Pragya Arora
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore - 560064, India
| | - A K Sood
- Department of Physics, Indian Institute of Science, Bangalore- 560012, India
- International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore - 560064, India
| | - Rajesh Ganapathy
- International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore - 560064, India
- School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore - 560064, India
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6
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Mustakim M, Kumar AVA. Depletion Induced Demixing and Crystallization in Binary Colloids Subjected to an External Potential Barrier. J Phys Chem B 2021; 126:327-335. [PMID: 34961314 DOI: 10.1021/acs.jpcb.1c08591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Depletion interaction plays an important role in determining the structural and dynamical properties of binary colloidal mixtures. We have investigated the effect of the attractive depletion interaction between an external potential barrier and larger species in the binary mixture on the phase behavior of a binary colloidal mixture using canonical-isokinetic ensemble molecular dynamics simulations. The demixing of the binary mixture due to this depletion interaction increases as the volume fraction increases, and a pure phase of larger particles forms in the region of the potential barrier. The local density of this pure phase is high enough that a face centered cubic crystalline domain is formed at this region. This crystalline phase diffuses perpendicular to the external potential barrier, indicating that moving crystals can be obtained in an equilibrium system. The temperature dependence of diffusivity of larger particles is non-Arrhenius and changes from sub-Arrhenius to super-Arrhenius as the volume fraction increases. This crossover from sub-Arrhenius to super-Arrhenius diffusion coincides with the crystalline formation near the potential barrier.
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Affiliation(s)
- Mahammad Mustakim
- School of Physical Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar 752050, India
| | - A V Anil Kumar
- School of Physical Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar 752050, India
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7
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Luo C, Janssen LMC. Glassy dynamics of sticky hard spheres beyond the mode-coupling regime. SOFT MATTER 2021; 17:7645-7661. [PMID: 34373889 PMCID: PMC8900603 DOI: 10.1039/d1sm00712b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 08/04/2021] [Indexed: 06/13/2023]
Abstract
Sticky hard spheres, i.e., hard particles decorated with a short-ranged attractive interaction potential, constitute a relatively simple model with highly non-trivial glassy dynamics. The mode-coupling theory of the glass transition (MCT) offers a qualitative account of the complex reentrant dynamics of sticky hard spheres, but the predicted glass transition point is notoriously underestimated. Here we apply an improved first-principles-based theory, referred to as generalized mode-coupling theory (GMCT), to sticky hard spheres. This theoretical framework seeks to go beyond MCT by hierarchically expanding the dynamics in higher-order density correlation functions. We predict the phase diagrams from the first few levels of the GMCT hierarchy and the dynamics-related critical exponents, all of which are much closer to the empirical observations than MCT. Notably, the prominent reentrant glassy dynamics, the glass-glass transition, and the higher-order bifurcation singularity classes (A3 and A4) of sticky hard spheres are found to be preserved within GMCT at arbitrary order. Moreover, we demonstrate that when the hierarchical order of GMCT increases, the effect of the short-ranged attractive interactions becomes more evident in the dynamics. This implies that GMCT is more sensitive to subtle microstructural differences than MCT, and that the framework provides a promising first-principles approach to systematically go beyond the MCT regime.
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Affiliation(s)
- Chengjie Luo
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands.
| | - Liesbeth M C Janssen
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands.
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8
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Ma X, Mishra CK, Habdas P, Yodh AG. Structural and short-time vibrational properties of colloidal glasses and supercooled liquids in the vicinity of the re-entrant glass transition. J Chem Phys 2021; 155:074902. [PMID: 34418931 DOI: 10.1063/5.0059084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We investigate the short-time vibrational properties and structure of two-dimensional, bidisperse, colloidal glasses and supercooled liquids in the vicinity of the re-entrant glass transition, as a function of interparticle depletion attraction strength. The long-time spatiotemporal dynamics of the samples are measured to be non-monotonic, confirming that the suspensions evolve from repulsive glass to supercooled liquid to attractive glass with increasing depletion attraction. Here, we search for vibrational signatures of the re-entrant behavior in the short-time spatiotemporal dynamics, i.e., dynamics associated with particle motion inside its nearest-neighbor cage. Interestingly, we observe that the anharmonicity of these in-cage vibrations varies non-monotonically with increasing attraction strength, consistent with the non-monotonic long-time structural relaxation dynamics of the re-entrant glass. We also extract effective spring constants between neighboring particles; we find that spring stiffness involving small particles also varies non-monotonically with increasing attraction strength, while stiffness between large particles increases monotonically. Last, from study of depletion-dependent local structure and vibration participation fractions, we gain microscopic insight into the particle-size-dependent contributions to short-time vibrational modes in the glass and supercooled liquid states.
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Affiliation(s)
- Xiaoguang Ma
- Center for Complex Flows and Soft Matter Research, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Chandan K Mishra
- Discipline of Physics, Indian Institute of Technology (IIT) Gandhinagar Palaj, Gandhinagar, Gujarat 382355, India
| | - P Habdas
- Department of Physics, Saint Joseph's University, Philadelphia, Pennsylvania 19131, USA
| | - A G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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9
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Goujard S, Suau JM, Chaub A, Guigner JM, Bizien T, Cloitre M. Glassy states in adsorbing surfactant-microgel soft nanocomposites. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:404003. [PMID: 34237714 DOI: 10.1088/1361-648x/ac1282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
Mixtures of polymer-colloid hybrids such as star polymers and microgels with non-adsorbing polymeric additives have received a lot of attention. In these materials, the interplay between entropic forces and softness is responsible for a wealth of phenomena. By contrast, binary mixtures where one component can adsorb onto the other one have been far less studied. Yet real formulations in applications often contain low molecular weight additives that can adsorb onto soft colloids. Here we study the microstructure and rheology of soft nanocomposites made of surfactants and microgels using linear and nonlinear rheology, SAXS experiments, and cryo-TEM techniques. The results are used to build a dynamical state diagram encompassing various liquid, glassy, jammed, metastable, and reentrant liquid states, which results from a subtle interplay between enthalpic, entropic, and kinetic effects. We rationalize the rheological properties of the nanocomposites in each domain of the state diagram, thus providing exquisite solutions for designing new rheology modifiers at will.
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Affiliation(s)
- Sarah Goujard
- Molecular, Macromolecular Chemistry and Materials, ESPCI Paris, CNRS, PSL University, 10 Rue Vauquelin, 75005 Paris, France
| | | | - Arnaud Chaub
- Molecular, Macromolecular Chemistry and Materials, ESPCI Paris, CNRS, PSL University, 10 Rue Vauquelin, 75005 Paris, France
| | - Jean-Michel Guigner
- Sorbonne Université, CNRS, UMR 7590 Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC)-IRD-MNHN, 75005 Paris, France
| | - Thomas Bizien
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin BP 48, Gif-sur-Yvette 91190, France
| | - Michel Cloitre
- Molecular, Macromolecular Chemistry and Materials, ESPCI Paris, CNRS, PSL University, 10 Rue Vauquelin, 75005 Paris, France
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10
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Parisi D, Camargo M, Makri K, Gauthier M, Likos CN, Vlassopoulos D. Effect of softness on glass melting and re-entrant solidification in mixtures of soft and hard colloids. J Chem Phys 2021; 155:034901. [PMID: 34293891 DOI: 10.1063/5.0055381] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a systematic investigation of the structure and dynamic properties of model soft-hard colloidal mixtures. Results of a coarse-grained theoretical model are contrasted with rheological data, where the soft and hard colloids are mimicked by large star polymers with high functionality as the soft component and smaller stars with ultrahigh functionality as the hard one. Previous work by us revealed the recovery of the ergodicity of glassy soft star solutions and subsequent arrested phase separation and re-entrant solid transition upon progressive addition of small hard depletants. Here, we use different components to show that a small variation in softness has a significant impact on the state diagram of such mixtures. In particular, we establish that rendering the soft component more penetrable and modifying the size ratio bring about a remarkable shift in both the phase separation region and the glass-melting line so that the region of restored ergodicity can be notably enhanced and extended to much higher star polymer concentrations than for pure systems. We further rationalize our findings by analyzing the features of the depletion interaction induced by the smaller component that result from the interplay between the size ratio and the softness of the large component. These results demonstrate the great sensitivity of the phase behavior of entropic mixtures to small changes in the molecular architecture of the soft stars and point to the importance of accounting for details of the internal microstructure of soft colloidal particles for tailoring the flow properties of soft composites.
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Affiliation(s)
- Daniele Parisi
- FORTH, Institute of Electronic Structure and Laser, 70013 Heraklion, Crete, Greece
| | - Manuel Camargo
- CICBA & FIMEB, Universidad Antonio Nariño-Campus Farallones, Km 18 via Cali-Jamundi, 760030 Cali, Colombia
| | - Kalliopi Makri
- FORTH, Institute of Electronic Structure and Laser, 70013 Heraklion, Crete, Greece
| | - Mario Gauthier
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Christos N Likos
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
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11
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Kim HS, Xu Y, Scheffold F, Mason TG. Self-motion and heterogeneous droplet dynamics in moderately attractive dense emulsions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:175101. [PMID: 33513598 DOI: 10.1088/1361-648x/abe157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
We show that diffusing wave spectroscopy (DWS) is sensitive to the presence of a moderate short-range attraction between droplets in uniform fractionated colloidal emulsions near and below the jamming point associated with monodisperse hard spheres. This moderate interdroplet attraction, induced by micellar depletion, has an energy of about ∼2.4kBT, only somewhat larger than thermal energy. Although changes in the mean free path of optical transport caused by this moderate depletion attraction are small, DWS clearly reveals an additional secondary decay-to-plateau in the intensity autocorrelation function at long times that is not present when droplet interactions are nearly hard. We hypothesize that this secondary decay-to-plateau does not reflect the average self-motion of individual droplets experiencing Brownian excitations, but instead results from heterogeneous dynamics involving a sub-population of droplets that still experience bound motion yet with significantly larger displacements than the average. By effectively removing the contribution of this secondary decay-to-plateau, which is linked to greater local heterogeneity in droplet structure caused by the moderate attraction, we obtain self-motion mean square displacements (MSDs) of droplets that reflect only the initial primary decay-to-plateau. Moreover, we show that droplet self-motion primary plateau MSDs can be interpreted using the generalized Stokes-Einstein relation of passive microrheology, yielding quantitative agreement with plateau elastic shear moduli measured mechanically.
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Affiliation(s)
- Ha Seong Kim
- Department of Chemistry and Biochemistry, University of California- Los Angeles, Los Angeles, CA 90095, United States of America
| | - Yixuan Xu
- Department of Materials Science and Engineering, University of California- Los Angeles, Los Angeles, CA 90095, United States of America
| | - Frank Scheffold
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Thomas G Mason
- Department of Chemistry and Biochemistry, University of California- Los Angeles, Los Angeles, CA 90095, United States of America
- Department of Physics and Astronomy, University of California- Los Angeles, Los Angeles, CA 90095, United States of America
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12
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Gordon MB, Kloxin CJ, Wagner NJ. Structural and rheological aging in model attraction-driven glasses by Rheo-SANS. SOFT MATTER 2021; 17:924-935. [PMID: 33245305 DOI: 10.1039/d0sm01373k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Aging in a model colloidal suspension comprised of particles with a thermoreversible attraction is studied using Rheo-SANS techniques in the attractive-driven glass state. Multiple thermal pathways lead to a common rheological and microstructural aging trajectory, as was observed previously for a thermoreversible gel. SANS measurements of the colloidal glass microstructure as a function of temperature and time during various quench protocols are quantitatively characterized in terms of an effective interaction strength that becomes an order parameter defining the microstructural state of the glass. Using previously validated concepts of a fictive temperature, a semi-empirical, quantitative relationship similar to an Avrami relationship is established between the mechanical aging (elastic modulus) and microstructural aging (order parameter) that is independent of thermal history for the thermal profiles studied herein at long times. Furthermore, shear rejuvenation is studied, and while shear may only partially reduce the degree of structure in the glass, aging upon flow cessation is found to follow a common trajectory when viewed in terms of the microstructural order parameter.
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Affiliation(s)
- Melissa B Gordon
- Department of Chemical and Biomolecular Engineering, Lafayette College, 740 High Street, Easton, PA 18042, USA
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13
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Fullerton CJ, Berthier L. Glassy Behavior of Sticky Spheres: What Lies beyond Experimental Timescales? PHYSICAL REVIEW LETTERS 2020; 125:258004. [PMID: 33416397 DOI: 10.1103/physrevlett.125.258004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/21/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
We use the swap Monte Carlo algorithm to analyze the glassy behavior of sticky spheres in equilibrium conditions at densities where conventional simulations and experiments fail to reach equilibrium, beyond predicted phase transitions and dynamic singularities. We demonstrate the existence of a unique ergodic region comprising all the distinct phases previously reported, except for a phase-separated region at strong adhesion. All structural and dynamic observables evolve gradually within this ergodic region, the physics evolving smoothly from well-known hard sphere glassy behavior at small adhesions and large densities, to a more complex glassy regime characterized by unusually broad distributions of relaxation timescales and length scales at large adhesions.
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Affiliation(s)
- Christopher J Fullerton
- Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, 34095 Montpellier, France
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Ludovic Berthier
- Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, 34095 Montpellier, France
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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14
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Scale invariance in a nonvibrating magnetic granular system. Sci Rep 2020; 10:11474. [PMID: 32651442 PMCID: PMC7351748 DOI: 10.1038/s41598-020-68345-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 06/19/2020] [Indexed: 11/24/2022] Open
Abstract
A nonvibrating magnetic granular system is studied by using a time series approach. The system consists of steel balls confined inside a circular wall that surrounds a glass plate. Kinetic energy is provided to the particles by the application of an external vertical time-dependent magnetic field of different amplitudes. We carried out a characterization of the system dynamics through the measurement of the correlations present in the time series of positions, in the x-direction, of each particle. In particular, by performing Fourier spectral analysis, we find that the time series are fractal and scale invariant, in such a way that the corresponding Fourier power spectra follow a power law \documentclass[12pt]{minimal}
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\begin{document}$$0<\beta <2.5$$\end{document}0<β<2.5. More specifically, we find that the values of \documentclass[12pt]{minimal}
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\begin{document}$$\beta$$\end{document}β, and therefore the strength of the correlations, increase as the magnetic field also increases. In this way, the present system constitutes an experimental model to generate correlated random walks. Additionally, we show how the introduction of a constant magnetic field breaks down this scale invariance property in the positions of each particle. Finally, we confirm the above results by applying detrended fluctuation analysis.
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15
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Zirdehi EM, Voigtmann T, Varnik F. Multiple character of non-monotonic size-dependence for relaxation dynamics in polymer-particle and binary mixtures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:275104. [PMID: 32287041 DOI: 10.1088/1361-648x/ab757c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Adding plasticizers is a well-known procedure to reduce the glass transition temperature in polymers. It has been recently shown that this effect shows a non-monotonic dependence on the size of additive molecules (2019 J. Chem. Phys. 150 024903). In this work, we demonstrate that, as the size of the additive molecules is changed at fixed concentration, multiple extrema emerge in the dependence of the system's relaxation time on the size ratio. The effect occurs on all relevant length scales including single monomer dynamics, decay of Rouse modes and relaxation of the chain's end-to-end vector. A qualitatively similar trend is found within mode-coupling theoretical results for a binary hard-sphere mixture. An interpretation of the effect in terms of local packing efficiency and coupling between the dynamics of minority and majority species is provided.
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Affiliation(s)
- Elias M Zirdehi
- Interdisciplinary Centre for Advanced Materials Simulation (ICAMS), Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
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16
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Ghosh A, Schweizer KS. Microscopic theory of the influence of strong attractive forces on the activated dynamics of dense glass and gel forming fluids. J Chem Phys 2019; 151:244502. [DOI: 10.1063/1.5129941] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Ashesh Ghosh
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois 61801, USA
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois 61801, USA
| | - Kenneth S. Schweizer
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois 61801, USA
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois 61801, USA
- Department of Material Science, University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois 61801, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois 61801, USA
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Marín-Aguilar S, Wensink HH, Foffi G, Smallenburg F. Slowing down supercooled liquids by manipulating their local structure. SOFT MATTER 2019; 15:9886-9893. [PMID: 31799588 DOI: 10.1039/c9sm01746a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Glasses remain an elusive and poorly understood state of matter. It is not clear how we can control the macroscopic dynamics of glassy systems by tuning the properties of their microscopic building blocks. In this paper, we propose a simple directional colloidal model that reinforces the optimal icosahedral local structure of binary hard-sphere glasses. We show that this specific symmetry results in a dramatic slowing down of the dynamics. Our results open the door to controlling the dynamics of dense glassy systems by selectively promoting specific local structural environments.
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Affiliation(s)
- Susana Marín-Aguilar
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France.
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18
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Germain P, Amokrane S. Glass transition and reversible gelation in asymmetric binary mixtures: A study by mode coupling theory and molecular dynamics. Phys Rev E 2019; 100:042614. [PMID: 31770885 DOI: 10.1103/physreve.100.042614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Indexed: 06/10/2023]
Abstract
The glass transition and the binodals of asymmetric binary mixtures are investigated from the effective fluid approach in the mode coupling theory and by molecular dynamics. Motivated by previous theoretical predictions, the hard-sphere mixture and the Asakura-Oosawa models are used to analyze experimental results from the literature, relative to polystyrene spheres mixed either with linear polymers or with dense microgel particles. In agreement with the experimental observations, the specificity of the depletant particles is shown to favor lower density gels. It further favors equilibrium gelation by reducing also the tendency of the system to phase separate. These results are confirmed by a phenomenological modification of the mode coupling theory in which the vertex functions are computed at an effective density lower than the actual one. A model effective potential in asymmetric mixtures of hard particles is used to further check this phenomenological modification against molecular dynamics simulation.
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Affiliation(s)
- Ph Germain
- Physique des Liquides et Milieux Complexes, Faculté des Sciences et Technologie, Université Paris Est (Créteil), 61 Avenue du Général de Gaulle, 94010 Créteil Cedex, France
| | - S Amokrane
- Physique des Liquides et Milieux Complexes, Faculté des Sciences et Technologie, Université Paris Est (Créteil), 61 Avenue du Général de Gaulle, 94010 Créteil Cedex, France
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Mishra CK, Habdas P, Yodh AG. Dynamic Heterogeneities in Colloidal Supercooled Liquids: Experimental Tests of Inhomogeneous Mode Coupling Theory. J Phys Chem B 2019; 123:5181-5188. [PMID: 31132279 DOI: 10.1021/acs.jpcb.9b03419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dynamics in supercooled liquids slow enormously upon approaching the glass transition, albeit without significant change of liquid structure. This empirical observation has stimulated development of many theoretical models which attempt to elucidate microscopic mechanisms in glasses and glass precursors. Here, quasi-two-dimensional colloidal supercooled liquids and glasses are employed to experimentally test predictions of widely used models: mode coupling theory (MCT) and its important extension, inhomogeneous MCT (IMCT). We measure two-point dynamic correlation functions in the glass forming liquids to determine structural relaxation times, τα, and mode coupling exponents, a, b, and γ; these parameters are then used to extract the mode coupling dynamic crossover packing area-fraction, ϕ c. This information, along with our measurements of supercooled liquid spatiotemporal dynamics, permits characterization of dynamic heterogeneities in the samples and facilitates direct experimental tests of the scaling predictions of IMCT. The time scales at which dynamic heterogeneities are largest, and their spatial sizes, exhibit power law growth on approaching ϕ c. Within experimental error, the exponents of the measured power laws are close to the predictions of IMCT.
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Affiliation(s)
- Chandan K Mishra
- Department of Physics and Astronomy , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Piotr Habdas
- Department of Physics , Saint Joseph's University , Philadelphia , Pennsylvania 19131 , United States
| | - A G Yodh
- Department of Physics and Astronomy , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
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20
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Lázaro-Lázaro E, Perera-Burgos JA, Laermann P, Sentjabrskaja T, Pérez-Ángel G, Laurati M, Egelhaaf SU, Medina-Noyola M, Voigtmann T, Castañeda-Priego R, Elizondo-Aguilera LF. Glassy dynamics in asymmetric binary mixtures of hard spheres. Phys Rev E 2019; 99:042603. [PMID: 31108620 DOI: 10.1103/physreve.99.042603] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Indexed: 06/09/2023]
Abstract
We perform a systematic and detailed study of the glass transition in highly asymmetric binary mixtures of colloidal hard spheres, combining differential dynamic microscopy experiments, event-driven molecular dynamics simulations, and theoretical calculations, exploring the whole state diagram and determining the self-dynamics and collective dynamics of both species. Two distinct glassy states involving different dynamical arrest transitions are consistently described, namely, a double glass with the simultaneous arrest of the self-dynamics and collective dynamics of both species, and a single glass of large particles in which the self-dynamics of the small species remains ergodic. In the single-glass scenario, spatial modulations in the collective dynamics of both species occur due to the structure of the large spheres, a feature not observed in the double-glass domain. The theoretical results, obtained within the self-consistent generalized Langevin equation formalism, are in agreement with both simulations and experimental data, thus providing a stringent validation of this theoretical framework in the description of dynamical arrest in highly asymmetric mixtures. Our findings are summarized in a state diagram that classifies the various amorphous states of highly asymmetric mixtures by their dynamical arrest mechanisms.
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Affiliation(s)
- Edilio Lázaro-Lázaro
- Instituto de Física Manuel Sandoval Vallarta, Universidad Autónoma de San Luis Potosí, Alvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí, Mexico
| | - Jorge Adrián Perera-Burgos
- CONACYT-Unidad de Ciencias del Agua, Centro de Investigación Científica de Yucatán A.C. (CICY), Calle 8, No. 39, Mz. 29, S.M. 64, 77524 Cancún, Quintana Roo, Mexico
| | - Patrick Laermann
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Tatjana Sentjabrskaja
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Gabriel Pérez-Ángel
- Departamento de Física Aplicada, Cinvestav, Unidad Mérida, Apartado Postal 73 Cordemex, 97310 Mérida, Yucatán, Mexico
| | - Marco Laurati
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstraße 1, 40225 Düsseldorf, Germany
- Departamento de Ingeniería Física, División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico
| | - Stefan U Egelhaaf
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Magdaleno Medina-Noyola
- Instituto de Física Manuel Sandoval Vallarta, Universidad Autónoma de San Luis Potosí, Alvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí, Mexico
- Departamento de Ingeniería Física, División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico
| | - Thomas Voigtmann
- Department of Physics, Heinrich Heine University, Universitätsstraße 1, 40225 Düsseldorf, Germany
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft-und Raumfahrt (DLR), Linder Höhe 51170, Köln, Germany
| | - 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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Ruiz-Franco J, Gnan N, Zaccarelli E. Rheological investigation of gels formed by competing interactions: A numerical study. J Chem Phys 2019; 150:024905. [DOI: 10.1063/1.5052317] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- José Ruiz-Franco
- Dipartimento di Fisica, Sapienza Univesità di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
| | - Nicoletta Gnan
- Dipartimento di Fisica, Sapienza Univesità di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
- CNR-ISC, UOS Sapiena, 00185 Roma, Italy
| | - Emanuela Zaccarelli
- Dipartimento di Fisica, Sapienza Univesità di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
- CNR-ISC, UOS Sapiena, 00185 Roma, Italy
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22
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Schneider J, Werner M, Bartsch E. New insights into re-entrant melting of microgel particles by polymer-induced aggregation experiments. SOFT MATTER 2018; 14:3811-3817. [PMID: 29717726 DOI: 10.1039/c7sm01922j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
While microgels are in general described as soft particles, polystyrene (PS) microgels can be synthesized in a way that cross-link density has only a minor influence on their physical properties. Even though the particles swell in a good solvent, the imparted slight softness still allows a mapping on hard sphere behaviour for a large range of cross-link densities [Schneider et al., Soft Matter, 2017, 13, 445]. Nevertheless, the hard sphere analogy breaks down as soon as polymer chains are added to these systems. Quantitative differences between PS microgels and true hard sphere systems appear and the differences between stronger and weaker cross-linked PS microgels can be observed. To gain deeper insights into the origin of these deviations from true hard sphere behaviour, this work is addressed to a systematic study of the colloid-polymer interactions in PS microgel-polymer mixtures. We investigated the aggregation behaviour (namely aggregation concentration and cluster structure) as a function of colloid size, cross-link density and colloid-polymer size ratio in very dilute colloidal suspensions. Our results show that the interplay of cross-link density and polymer size is a key parameter for the strength of the colloid-polymer interactions. Furthermore, the centre-to-centre distance of the colloidal particles in the formed clusters decreases if the cross-link density is decreased, allowing for a higher packing density. This may also explain the unusually high fluid packing fractions observed in the re-entry region of the phase diagram of PS microgel-free PS polymer mixtures.
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Affiliation(s)
- Jochen Schneider
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität, D-79104 Freiburg, Germany.
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Padmanabhan P, Zia R. Gravitational collapse of colloidal gels: non-equilibrium phase separation driven by osmotic pressure. SOFT MATTER 2018; 14:3265-3287. [PMID: 29637976 DOI: 10.1039/c8sm00002f] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Delayed gravitational collapse of colloidal gels is characterized by initially slow compaction that gives way to rapid bulk collapse, posing interesting questions about the underlying mechanistic origins. Here we study gel collapse utilizing large-scale dynamic simulation of a freely draining gel of physically bonded particles subjected to gravitational forcing. The hallmark regimes of collapse are recovered: slow compaction, transition to rapid collapse, and long-time densification. Microstructural changes are monitored by tracking particle positions, coordination number, and bond dynamics, along with volume fraction, osmotic pressure, and potential energy. Together these reveal the surprising result that collapse can occur with a fully intact network, where the tipping point arises when particle migration dissolves strands in a capillary-type instability. While it is possible for collapse to rupture a gel network into clusters that then sediment, and hydrodynamic interactions can make interesting contributions, neither is necessary. Rather, we find that the "delay" arises from gravity-enhanced coarsening, which triggers the re-emergence of phase separation. The mechanism of this transition is a leap toward lower potential energy of the gel, driven by bulk negative osmotic pressure that condenses the particle phase: the gel collapses in on itself under negative osmotic pressure allowing the gel, to tunnel through the equilibrium phase diagram to a higher volume fraction "state". Remarkably, collapse stops when condensation stops, when gravitational advection produces a positive osmotic pressure, re-arresting the gel.
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Affiliation(s)
- Poornima Padmanabhan
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA
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24
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Konincks T, Krakoviack V. Dynamics of fluids in quenched-random potential energy landscapes: a mode-coupling theory approach. SOFT MATTER 2017; 13:5283-5297. [PMID: 28677713 DOI: 10.1039/c7sm00984d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Motivated by a number of recent experimental and computational studies of the dynamics of fluids plunged in quenched-disordered external fields, we report on a theoretical investigation of this topic within the framework of the mode-coupling theory, based on the simple model of the hard-sphere fluid in a Gaussian random field. The possible dynamical arrest scenarios driven by an increase of the disorder strength and/or of the fluid density are mapped, and the corresponding evolutions of time-dependent quantities typically used for the characterization of anomalous self-diffusion are illustrated with detailed computations. Overall, a fairly reasonable picture of the dynamics of the system at hand is outlined, which in particular involves a non-monotonicity of the self-diffusion coefficient with fluid density at fixed disorder strength, in agreement with experiments. The disorder correlation length is shown to have a strong influence on the latter feature.
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Affiliation(s)
- Thomas Konincks
- Univ Lyon, ENS de Lyon, CNRS UMR 5182, Université Claude Bernard Lyon 1, Laboratoire de Chimie, F-69342, Lyon, France.
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25
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Li Q, Peng X, McKenna GB. Long-term aging behaviors in a model soft colloidal system. SOFT MATTER 2017; 13:1396-1404. [PMID: 28120996 DOI: 10.1039/c6sm02408d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Colloidal and molecular systems share similar behaviors near to the glass transition volume fraction or temperature. Here, aging behaviors after volume fraction up-jump (induced by performing temperature down-jumps) conditions for a PS-PNIPAM/AA soft colloidal system were investigated using light scattering (diffusing wave spectroscopy, DWS). Both aging responses and equilibrium dynamics were investigated. For the aging responses, long-term experiments (100 000 s) were performed, and both equilibrium and non-equilibrium behaviors of the system were obtained. In the equilibrium state, as effective volume fraction increases (or temperature decreases), the colloidal dispersion displays a transition from the liquid to a glassy state. The equilibrium α-relaxation dynamics strongly depend on both the effective volume fraction and the initial mass concentration for the studied colloidal systems. Compared with prior results from our lab [X. Di, X. Peng and G. B. McKenna, J. Chem. Phys., 2014, 140, 054903], the effective volume fractions investigated spanned a wider range, to deeper into the glassy domain. The results show that the α-relaxation time τα of the samples aged into equilibrium deviate from the classical Vogel-Fulcher-Tammann (VFT)-type expectations and the super-Arrhenius signature disappears above the glass transition volume fraction. The non-equilibrium aging response shows that the time for the structural evolution into equilibrium and the α-relaxation time are decoupled. The DWS investigation of the aging behavior after different volume fraction jumps reveals a different non-equilibrium or aging behavior for the considered colloidal systems compared with either molecular glasses or the macroscopic rheology of a similar colloidal dispersions.
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Affiliation(s)
- Qi Li
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, USA.
| | - Xiaoguang Peng
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, USA.
| | - Gregory B McKenna
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, USA.
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Schneider J, Wiemann M, Rabe A, Bartsch E. On tuning microgel character and softness of cross-linked polystyrene particles. SOFT MATTER 2017; 13:445-457. [PMID: 27905616 DOI: 10.1039/c6sm02007k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Polystyrene (PS) microgel colloids have often been used successfully to model hard sphere behaviour even though the term "gel" invokes inevitably the notion of a more or less soft, deformable object. Here we systematically study the effect of reducing the cross-link density from 1 : 10 (1 cross-link per 10 monomers) to 1 : 100 on particle interactions and "softness". We report on the synthesis and purification of 1 : 10, 1 : 25, 1 : 50, 1 : 75 and 1 : 100 cross-linked PS particles and their characterization in terms of single particle properties, as well as the behaviour of concentrated dispersions. We are able to tune particle softness in the range between soft PNiPAM-microgels and hard PMMA particles while still allowing the mapping of the microgels onto hard sphere behavior with respect to phase diagram and static structure factors. This is mainly due to a rather homogeneous radial distribution of cross-links in contrast to PNiPAM microgels where the cross-link density decreases radially. We find that up to a cross-link density of 1 : 50 particle form factors are perfectly described by a homogeneous sphere model whereas 1 : 75 and 1 : 100 cross-linked spheres are slightly better described as fuzzy spheres. However the fuzziness is rather small compared to typical PNiPAM microgels so that a hard sphere mapping still holds even for these low cross-link densities. Finally, by varying the reaction conditions - changing from batch to semibatch emulsion polymerization and varying the feed rate or by adjusting the monomer to initiator ratio we can tune the fuzziness or significantly alter the inner structure to a more open, star-like architecture.
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Affiliation(s)
- Jochen Schneider
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität, D-79104 Freiburg, Germany.
| | - Malte Wiemann
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität, D-79104 Freiburg, Germany.
| | - Anna Rabe
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität, D-79104 Freiburg, Germany.
| | - Eckhard Bartsch
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität, D-79104 Freiburg, Germany. and Institut für Makromolekulare Chemie, Albert-Ludwigs-Universität, D-79104 Freiburg, Germany
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Roldán-Vargas S, Rovigatti L, Sciortino F. Connectivity, dynamics, and structure in a tetrahedral network liquid. SOFT MATTER 2017; 13:514-530. [PMID: 27935002 DOI: 10.1039/c6sm02282k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report a detailed computational study by Brownian dynamics simulations of the structure and dynamics of a liquid of patchy particles which forms an amorphous tetrahedral network upon decreasing the temperature. The highly directional particle interactions allow us to investigate the system connectivity by discriminating the total set of particles into different populations according to a penta-modal distribution of bonds per particle. With this methodology we show how the particle bonding process is not randomly independent but it manifests clear bond correlations at low temperatures. We further explore the dynamics of the system in real space and establish a clear relation between particle mobility and particle connectivity. In particular, we provide evidence of anomalous diffusion at low temperatures and reveal how the dynamics is affected by the short-time hopping motion of the weakly bounded particles. Finally we widely investigate the dynamics and structure of the system in Fourier space and identify two quantitatively similar length scales, one dynamic and the other static, which increase upon cooling the system and reach distances of the order of few particle diameters. We summarize our findings in a qualitative picture where the low temperature regime of the viscoelastic liquid is understood in terms of an evolving network of long time metastable cooperative domains of particles.
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Affiliation(s)
- Sándalo Roldán-Vargas
- Max Planck Institute for the Physics of Complex Systems, D-01307, Dresden, Germany. and Department of Physics, Sapienza, Università di Roma, Piazzale Aldo Moro 2, I-00185, Roma, Italy
| | - Lorenzo Rovigatti
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria and Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford, OX1 3NP, UK
| | - Francesco Sciortino
- Department of Physics, Sapienza, Università di Roma, Piazzale Aldo Moro 2, I-00185, Roma, Italy
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28
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Tapia-Ignacio C, Garcia-Serrano J, Donado F. Nonvibrating granular model for a glass-forming liquid: Equilibration and aging. Phys Rev E 2016; 94:062902. [PMID: 28085297 DOI: 10.1103/physreve.94.062902] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Indexed: 11/06/2022]
Abstract
We studied experimentally a model of a glass-forming liquid on the basis of a nonvibrating magnetic granular system under an unsteady magnetic field. A sudden quenching was produced that drove the system from a liquid state to a different final state with lower temperature; the latter could be a liquid state or a solid state. We determined the mean-squared displacement in temporal windows to obtain the dynamic evolution of the system, and we determined the radial distribution function to obtain its structural characteristics. The results were analyzed using the intermediate scattering function and the effective potential between two particles. We observed that when quenching drives the system to a final state in the liquid phase far from the glass-transition temperature, equilibration occurs very quickly. When the final state has a temperature far below the glass-transition temperature, the system reaches its equilibrium state very quickly. In contrast, when the final state has an intermediate temperature but is below that corresponding to the glass transition, the system falls into a state that evolves slowly, presenting aging. The system evolves by an aging process toward more ordered states. However, after a waiting time, the dynamic behavior changes. It was observed that some particles get close enough to overpass the repulsive interactions and form small stable aggregates. In the effective potential curves, it was observed that the emergence of a second effective well due to the attraction quickly evolves and results in a deeper well than the initial effective well due to the repulsion. With the increase in time, more particles fall in the attractive well forming inhomogeneities, which produce a frustration in the aging process.
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Affiliation(s)
- C Tapia-Ignacio
- Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Pachuca 42184, Hidalgo, Mexico
| | - J Garcia-Serrano
- Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Pachuca 42184, Hidalgo, Mexico
| | - F Donado
- Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Pachuca 42184, Hidalgo, Mexico
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29
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Capellmann RF, Valadez-Pérez NE, Simon B, Egelhaaf SU, Laurati M, Castañeda-Priego R. Structure of colloidal gels at intermediate concentrations: the role of competing interactions. SOFT MATTER 2016; 12:9303-9313. [PMID: 27801925 DOI: 10.1039/c6sm01822j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Colloidal gels formed by colloid-polymer mixtures with an intermediate volume fraction (ϕc ≈ 0.4) are investigated by confocal microscopy. In addition, we have performed Monte Carlo simulations based on a simple effective pair potential that includes a short-range attractive contribution representing depletion interactions, and a longer-range repulsive contribution describing the electrostatic interactions due to the presence of residual charges. Despite neglecting non-equilibrium effects, experiments and simulations yield similar gel structures, characterised by, e.g., the pair, angular and bond distribution functions. We find that the structure hardly depends on the strength of the attraction if the electrostatic contribution is fixed, but changes significantly if the electrostatic screening is changed. This delicate balance between attractions and repulsions, which we quantify by the second virial coefficient, also determines the location of the gelation boundary.
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Affiliation(s)
- Ronja F Capellmann
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Néstor E Valadez-Pérez
- División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 León, Guanajuato, Mexico.
| | - Benedikt Simon
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Stefan U Egelhaaf
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Marco Laurati
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany and División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 León, Guanajuato, Mexico.
| | - Ramón Castañeda-Priego
- División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 León, Guanajuato, Mexico.
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30
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Chandran S, Begam N, Sprung M, Basu J. Coherent X-ray scattering reveals nature of dynamical transitions in nanoparticle–polymer suspensions. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.07.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gratale MD, Ma X, Davidson ZS, Still T, Habdas P, Yodh AG. Vibrational properties of quasi-two-dimensional colloidal glasses with varying interparticle attraction. Phys Rev E 2016; 94:042606. [PMID: 27841543 DOI: 10.1103/physreve.94.042606] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Indexed: 06/06/2023]
Abstract
We measure the vibrational modes and particle dynamics of quasi-two-dimensional colloidal glasses as a function of interparticle interaction strength. The interparticle attractions are controlled via a temperature-tunable depletion interaction. Specifically, the interparticle attraction energy is increased gradually from a very small value (nearly hard-sphere) to moderate strength (∼4k_{B}T), and the variation of colloidal particle dynamics and vibrations are concurrently probed. The particle dynamics slow monotonically with increasing attraction strength, and the particle motions saturate for strengths greater than ∼2k_{B}T, i.e., as the system evolves from a nearly repulsive glass to an attractive glass. The shape of the phonon density of states is revealed to change with increasing attraction strength, and the number of low-frequency modes exhibits a crossover for glasses with weak compared to strong interparticle attraction at a threshold of ∼2k_{B}T. This variation in the properties of the low-frequency vibrational modes suggests a new means for distinguishing between repulsive and attractive glass states.
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Affiliation(s)
- Matthew D Gratale
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Xiaoguang Ma
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Complex Assemblies of Soft Matter, CNRS-Solvay-UPenn UMI 3254, Bristol, Pennsylvania 19007-3624, USA
| | - Zoey S Davidson
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tim Still
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Piotr Habdas
- Department of Physics, Saint Joseph's University, Philadelphia, Pennsylvania 19131, USA
| | - A G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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32
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Gratale MD, Still T, Matyas C, Davidson ZS, Lobel S, Collings PJ, Yodh AG. Tunable depletion potentials driven by shape variation of surfactant micelles. Phys Rev E 2016; 93:050601. [PMID: 27300818 DOI: 10.1103/physreve.93.050601] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Indexed: 06/06/2023]
Abstract
Depletion interaction potentials between micron-sized colloidal particles are induced by nanometer-scale surfactant micelles composed of hexaethylene glycol monododecyl ether (C_{12}E_{6}), and they are measured by video microscopy. The strength and range of the depletion interaction is revealed to arise from variations in shape anisotropy of the surfactant micelles. This shape anisotropy increases with increasing sample temperature. By fitting the colloidal interaction potentials to theoretical models, we extract micelle length and shape anisotropy as a function of temperature. This work introduces shape anisotropy tuning as a means to control interparticle interactions in colloidal suspensions, and it shows how the interparticle depletion potentials of micron-scale objects can be employed to probe the shape and size of surrounding macromolecules at the nanoscale.
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Affiliation(s)
- Matthew D Gratale
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tim Still
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Caitlin Matyas
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- The Arts Academy at Benjamin Rush, Philadelphia, Pennsylvania 19154, USA
| | - Zoey S Davidson
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Samuel Lobel
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Peter J Collings
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Physics and Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, USA
| | - A G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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33
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de Sousa N, Sáenz JJ, Scheffold F, García-Martín A, Froufe-Pérez LS. Self-diffusion and structural properties of confined fluids in dynamic coexistence. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:135101. [PMID: 26940756 DOI: 10.1088/0953-8984/28/13/135101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Self-diffusion and radial distribution functions are studied in a strongly confined Lennard-Jones fluid. Surprisingly, in the solid-liquid phase transition region, where the system exhibits dynamic coexistence, the self-diffusion constants are shown to present up to three-fold variations from solid to liquid phases at fixed temperature, while the radial distribution function corresponding to both the liquid and the solid phases are essentially indistinguishable.
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Affiliation(s)
- N de Sousa
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain
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Varnik F, Franosch T. Non-monotonic effect of confinement on the glass transition. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:133001. [PMID: 26940539 DOI: 10.1088/0953-8984/28/13/133001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The relaxation dynamics of glass forming liquids and their structure are influenced in the vicinity of confining walls. This effect has mostly been observed to be a monotonic function of the slit width. Recently, a qualitatively new behaviour has been uncovered by Mittal and coworkers, who reported that the single particle dynamics in a hard-sphere fluid confined in a planar slit varies in a non-monotonic way as the slit width is decreased from five to roughly two particle diametres (Mittal et al 2008 Phys. Rev. Lett. 100 145901). In view of the great potential of this effect for applications in those fields of science and industry, where liquids occur under strong confinement (e.g. nano-technology), the number of researchers studying various aspects and consequences of this non-monotonic behaviour has been rapidly growing. This review aims at providing an overview of the research activity in this newly emerging field. We first briefly discuss how competing mechanisms such as packing effects and short-range attraction may lead to a non-monotonic glass transition scenario in the bulk. We then analyse confinement effects on the dynamics of fluids using a thermodynamic route which relates the single particle dynamics to the excess entropy. Moreover, relating the diffusive dynamics to the Widom's insertion probability, the oscillations of the local dynamics with density at moderate densities are fairly well described. At high densities belonging to the supercooled regime, however, this approach breaks down signaling the onset of strongly collective effects. Indeed, confinement introduces a new length scale which in the limit of high densities and small pore sizes competes with the short-range local order of the fluid. This gives rise to a non-monotonic dependence of the packing structure on confinement, with a corresponding effect on the dynamics of structural relaxation. This non-monotonic effect occurs also in the case of a cone-plate type channel, where the degree of confinement varies with distance from the apex. This is a very promising issue for future research with the possibility of uncovering the existence of alternating glassy and liquid-like domains.
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Affiliation(s)
- Fathollah Varnik
- Interdisciplinary Centre for Advanced Materials Simulation (ICAMS), Ruhr-Universität Bochum, Universitätsstraße 150, D-44780 Bochum, Germany
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35
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Discontinuous nature of the repulsive-to-attractive colloidal glass transition. Sci Rep 2016; 6:22725. [PMID: 26940737 PMCID: PMC4778135 DOI: 10.1038/srep22725] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 02/17/2016] [Indexed: 01/02/2023] Open
Abstract
In purely repulsive colloidal systems a glass transition can be reached by increasing the particle volume fraction beyond a certain threshold. The resulting glassy state is governed by configurational cages which confine particles and restrict their motion. A colloidal glass may also be formed by inducing attractive interactions between the particles. When attraction is turned on in a repulsive colloidal glass a re-entrant solidification ensues. Initially, the repulsive glass melts as free volume in the system increases. As the attraction strength is increased further, this weakened configurational glass gives way to an attractive glass in which motion is hindered by the formation of physical bonds between neighboring particles. In this paper, we study the transition from repulsive-to-attractive glasses using three-dimensional imaging at the single-particle level. We show how the onset of cage weakening and bond formation is signalled by subtle changes in local structure. We then demonstrate the discontinuous nature of the solid-solid transition, which is marked by a critical onset at a threshold bonding energy. Finally, we highlight how the interplay between bonding and caging leads to complex and heterogeneous dynamics at the microscale.
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36
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Pandey R, Conrad JC. Gelation in mixtures of polymers and bidisperse colloids. Phys Rev E 2016; 93:012610. [PMID: 26871125 DOI: 10.1103/physreve.93.012610] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Indexed: 06/05/2023]
Abstract
We investigated the effects of varying the volume fraction of large particles (r) on the linear rheology and microstructure of mixtures of polymers and bidisperse colloids, in which the ratio of the small and large particle diameters was α=0.31 or α=0.45. Suspensions formulated at a total volume fraction of ϕ_{T}=0.15 and a constant concentration of polymer in the free volume c/c^{*}≈0.7 contained solid-like gels for small r and fluids or fluids of clusters at large r. The solid-like rheology and microstructure of these suspensions changed little with r when r was small, and fluidized only when r>0.8. By contrast, dense suspensions with ϕ_{T}=0.40 and α=0.31 contained solid-like gels at all concentrations of large particles and exhibited only modest rheological and microstructural changes upon varying the volume fraction of large particles. These results suggest that the effect of particle-size dispersity on the properties of colloid-polymer mixtures are asymmetric in particle size and are most pronounced near a gelation boundary.
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Affiliation(s)
- Rahul Pandey
- Department of Chemical & Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, USA
| | - Jacinta C Conrad
- Department of Chemical & Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, USA
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37
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Kurokawa A, Vidal V, Kurita K, Divoux T, Manneville S. Avalanche-like fluidization of a non-Brownian particle gel. SOFT MATTER 2015; 11:9026-9037. [PMID: 26403168 DOI: 10.1039/c5sm01259g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report on the fluidization dynamics of an attractive gel composed of non-Brownian particles made of fused silica colloids. Extensive rheology coupled to ultrasonic velocimetry allows us to characterize the global stress response together with the local dynamics of the gel during shear startup experiments. In practice, after being rejuvenated by a preshear, the gel is left to age for a time tw before being subjected to a constant shear rate [small gamma, Greek, dot above]. We investigate in detail the effects of both tw and [small gamma, Greek, dot above] on the fluidization dynamics and build a detailed state diagram of the gel response to shear startup flows. The gel may display either transient shear banding towards complete fluidization or steady-state shear banding. In the former case, we unravel that the progressive fluidization occurs by successive steps that appear as peaks on the global stress relaxation signal. Flow imaging reveals that the shear band grows until complete fluidization of the material by sudden avalanche-like events which are distributed heterogeneously along the vorticity direction and correlated to large peaks in the slip velocity at the moving wall. These features are robust over a wide range of tw and [small gamma, Greek, dot above] values, although the very details of the fluidization scenario vary with [small gamma, Greek, dot above]. Finally, the critical shear rate [small gamma, Greek, dot above]* that separates steady-state shear-banding from steady-state homogeneous flow depends on the width of the shear cell and exhibits a nonlinear dependence with tw. Our work brings about valuable experimental data on transient flows of attractive dispersions, highlighting the subtle interplay between shear, wall slip and aging whose modeling constitutes a major challenge that has not been met yet.
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Affiliation(s)
- Aika Kurokawa
- Earthquake Research Institute, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
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38
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Bucciarelli S, Casal-Dujat L, De Michele C, Sciortino F, Dhont J, Bergenholtz J, Farago B, Schurtenberger P, Stradner A. Unusual dynamics of concentration fluctuations in solutions of weakly attractive globular proteins. J Phys Chem Lett 2015; 6:4470-4. [PMID: 26505877 PMCID: PMC4655417 DOI: 10.1021/acs.jpclett.5b02092] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The globular protein γB-crystallin exhibits a complex phase behavior, where liquid-liquid phase separation characterized by a critical volume fraction ϕc = 0.154 and a critical temperature Tc = 291.8 K coexists with dynamical arrest on all length scales at volume fractions around ϕ ≈ 0.3-0.35, and an arrest line that extends well into the unstable region below the spinodal. However, although the static properties such as the osmotic compressibility and the static correlation length are in quantitative agreement with predictions for binary liquid mixtures, this is not the case for the dynamics of concentration fluctuations described by the dynamic structure factor S(q,t). Using a combination of dynamic light scattering and neutron spin echo measurements, we demonstrate that the competition between critical slowing down and dynamical arrest results in a much more complex wave vector dependence of S(q,t) than previously anticipated.
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Affiliation(s)
- Saskia Bucciarelli
- Physical
Chemistry, Department of Chemistry, Lund
University, SE-22100 Lund, Sweden
| | - Lucía Casal-Dujat
- Physical
Chemistry, Department of Chemistry, Lund
University, SE-22100 Lund, Sweden
| | | | - Francesco Sciortino
- Department
of Physics, Università di Roma La
Sapienza, I-00186 Roma, Italy
- CNR-ISC
Uos, Università di Roma La Sapienza, I-00186 Roma, Italy
| | - Jan Dhont
- Forschungszentrum
Jülich, Institute of Complex Systems (ICS), Soft Condensed
Matter (ICS-3), D-52425 Jülich, Germany
- Heinrich-Heine-Universität
Düsseldorf, Department of Physics, D-40225 Düsseldorf, Germany
| | - Johan Bergenholtz
- Physical
Chemistry, Department of Chemistry, Lund
University, SE-22100 Lund, Sweden
- Department
of Chemistry and Molecular Biology, University
of Gothenburg, SE-41296 Göteborg, Sweden
| | - Bela Farago
- Institut
Laue-Langevin, F-38042 Grenoble Cedex 9, France
| | - Peter Schurtenberger
- Physical
Chemistry, Department of Chemistry, Lund
University, SE-22100 Lund, Sweden
| | - Anna Stradner
- Physical
Chemistry, Department of Chemistry, Lund
University, SE-22100 Lund, Sweden
- E-mail:
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39
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Marzi D, Capone B, Marakis J, Merola MC, Truzzolillo D, Cipelletti L, Moingeon F, Gauthier M, Vlassopoulos D, Likos CN, Camargo M. Depletion, melting and reentrant solidification in mixtures of soft and hard colloids. SOFT MATTER 2015; 11:8296-8312. [PMID: 26356800 DOI: 10.1039/c5sm01551k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present extensive experimental and theoretical investigations on the structure, phase behavior, dynamics and rheology of model soft-hard colloidal mixtures realized with large, multiarm star polymers as the soft component and smaller, compact stars as the hard one. The number and length of the arms in star polymers control their softness, whereas the size ratio, the overall density and the composition are additional parameters varied for the mixtures. A coarse-grained theoretical strategy is employed to predict the structure of the systems as well as their ergodicity properties on the basis of mode coupling theory, for comparison with rheological measurements on the samples. We discovered that dynamically arrested star-polymer solutions recover their ergodicity upon addition of colloidal additives. At the same time the system displays demixing instability, and the binodal of the latter meets the glass line in a way that leads, upon addition of a sufficient amount of colloidal particles, to an arrested phase separation and reentrant solidification. We present evidence for a subsequent solid-to-solid transition well within the region of arrested phase separation, attributed to a hard-sphere-mixture type of glass, due to osmotic shrinkage of the stars at high colloidal particle concentrations. We systematically investigated the interplay of star functionality and size ratio with glass melting and demixing, and rationalized our findings by the depletion of the big stars due to the smaller colloids. This new depletion potential in which, contrary to the classic colloid-polymer case, the hard component depletes the soft one, has unique and novel characteristics and allows the calculation of phase diagrams for such mixtures. This work covers a broad range of soft-hard colloidal mixture compositions in which the soft component exceeds the hard one in size and provides general guidelines for controlling the properties of such complex mixtures.
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Affiliation(s)
- Daniela Marzi
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.
| | - Barbara Capone
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.
| | - John Marakis
- FORTH, Institute of Electronic Structure and Laser, Heraklion, Crete 70013, Greece and Department of Materials Science and Technology, University of Crete, Heraklion, Crete 71003, Greece
| | - Maria Consiglia Merola
- FORTH, Institute of Electronic Structure and Laser, Heraklion, Crete 70013, Greece and Dipartimento di Ingegneria Industriale e dell' Informazione, Seconda Università di Napoli, Via Roma 21, 81031 Aversa, Caserta, Italy
| | - Domenico Truzzolillo
- FORTH, Institute of Electronic Structure and Laser, Heraklion, Crete 70013, Greece and Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France
| | - Luca Cipelletti
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France
| | - Firmin Moingeon
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Mario Gauthier
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Dimitris Vlassopoulos
- FORTH, Institute of Electronic Structure and Laser, Heraklion, Crete 70013, Greece and Department of Materials Science and Technology, University of Crete, Heraklion, Crete 71003, Greece
| | - Christos N Likos
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.
| | - Manuel Camargo
- Centro de Investigaciones en Ciencias Básicas y Aplicadas, Universidad Antonio Nariño - Campus Farallones, Km 18 via Cali-Jamundí, 760030 Santiago de Cali, Colombia.
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40
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Iglesias GR, Pirolt F, Tomšič M, Glatter O. Dynamics of liquid-crystalline emulsion droplets arrested in hydrogels: Addressing the multiple scattering problem in turbid systems. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2014.11.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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41
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Mallamace F, Corsaro C, Mallamace D, Chen SH. The fragile-to-strong dynamical crossover and the system viscoelasticity in attractive glass forming colloids. Colloid Polym Sci 2015. [DOI: 10.1007/s00396-015-3713-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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42
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Ndong Mintsa E, Germain P, Amokrane S. Bond lifetime and diffusion coefficient in colloids with short-range interactions. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2015; 38:21. [PMID: 25813606 DOI: 10.1140/epje/i2015-15021-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 02/20/2015] [Accepted: 02/23/2015] [Indexed: 06/04/2023]
Abstract
We use molecular dynamics simulations to study the influence of short-range structures in the interaction potential between hard-sphere-like colloidal particles. Starting from model potentials and effective potentials in binary mixtures computed from the Ornstein-Zernike equations, we investigate the influence of the range and strength of a possible tail beyond the usual core repulsion or the presence of repulsive barriers. The diffusion coefficient and mean "bond" lifetimes are used as indicators of the effect of this structure on the dynamics. The existence of correlations between the variations of these quantities with the physical parameters is discussed to assess the interpretation of dynamics slowing down in terms of long-lived bonds. We also discuss the question of a universal behaviour determined by the second virial coefficient B ((2)) and the interplay of attraction and repulsion. While the diffusion coefficient follows the B ((2)) law for purely attractive tails, this is no longer true in the presence of repulsive barriers. Furthermore, the bond lifetime shows a dependence on the physical parameters that differs from that of the diffusion coefficient. This raises the question of the precise role of bonds on the dynamics slowing down in colloidal gels.
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Affiliation(s)
- E Ndong Mintsa
- Laboratoire "Physique de Liquides et Milieux Complexes", Faculté des Sciences et Technologie, Université Paris-Est, Créteil, 61 avenue du Général de Gaulle, 94010, Créteil Cedex, France
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43
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Oskolkova MZ, Stradner A, Ulama J, Bergenholtz J. Concentration-dependent effective attractions between PEGylated nanoparticles. RSC Adv 2015. [DOI: 10.1039/c5ra00731c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Effective attractions between colloidal particles bearing a grafted PEG layer in water have been studied and, from a quantitative SANS analysis, are found to be concentration dependent.
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Affiliation(s)
- Malin Zackrisson Oskolkova
- Division of Physical Chemistry
- Center of Chemistry and Chemical Engineering
- Lund University
- SE-22100 Lund
- Sweden
| | - Anna Stradner
- Division of Physical Chemistry
- Center of Chemistry and Chemical Engineering
- Lund University
- SE-22100 Lund
- Sweden
| | - Jeanette Ulama
- Department of Chemistry and Molecular Biology
- University of Gothenburg
- SE-41296 Göteborg
- Sweden
| | - Johan Bergenholtz
- Division of Physical Chemistry
- Center of Chemistry and Chemical Engineering
- Lund University
- SE-22100 Lund
- Sweden
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44
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Sánchez-Miranda MJ, Sarmiento-Gómez E, Arauz-Lara JL. Brownian motion of optically anisotropic spherical particles in polymeric suspensions. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2015; 38:3. [PMID: 25618614 DOI: 10.1140/epje/i2015-15003-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/24/2014] [Accepted: 01/08/2015] [Indexed: 06/04/2023]
Abstract
We studied the rotational and translational diffusion of optically anisotropic liquid crystal particles embedded in semidiluted polymer solutions of Poly-Ethylene-Oxide (PEO) at different concentrations and different molecular weights. The polymer radius of gyration was chosen to be similar to the size of the probe particles and the polymer concentrations used are just above the crossover concentration. Thus, the system consists of solid probe particles moving in a sea of overlapping particles of similar size. We found that the behavior of both particle dynamics, rotational and translational, is similar in the range of concentrations considered here. In both cases, two linear diffusive regimes are observed, separated by a subdiffusive time interval. The spatial scale at which this intermediate regime appears shows a dependence on both the polymer concentration and molecular weight, and has a value similar to the thickness of the polymer-depleted layer usually found in this kind of systems. Additionally, we observe that the colloidal dynamic scales with the overlapping degree of the polymer particles.
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Affiliation(s)
- M J Sánchez-Miranda
- Instituto de Física "Manuel Sandoval Vallarta", Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, 78000, San Luis Potosí, SLP, México
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45
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Gnan N, Das G, Sperl M, Sciortino F, Zaccarelli E. Multiple glass singularities and isodynamics in a core-softened model for glass-forming systems. PHYSICAL REVIEW LETTERS 2014; 113:258302. [PMID: 25554913 DOI: 10.1103/physrevlett.113.258302] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Indexed: 06/04/2023]
Abstract
We investigate the slow dynamics of a simple glass former whose interaction potential is the sum of a hard core and a square shoulder repulsion. According to mode coupling theory, the competition between the two repulsive length scales gives rise to a complex dynamic scenario: besides the fluid-glass line, the theory predicts a glass-glass line in the temperature-packing fraction plane with two end points. Interestingly, for critical values of the square-shoulder parameters, such end points can be accessed from the liquid phase. We verify, via extensive numerical simulations, the existence of both points through the observation of an unconventional subdiffusive/logarithmic dynamical behavior. Unexpectedly, we also discover that the simultaneous presence of two end points generates special loci in the state diagram along which the dynamics is identical at all length and time scales.
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Affiliation(s)
- Nicoletta Gnan
- CNR-ISC Uos Sapienza, Piazzale A. Moro 2, I-00185 Roma, Italy
| | - Gayatri Das
- Dipartimento di Fisica, Sapienza Universitá di Roma, Piazzale A. Moro 2, I-00185 Roma, Italy
| | - Matthias Sperl
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft-und Raumfahrt, 51170 Köln, Germany
| | - Francesco Sciortino
- Dipartimento di Fisica, Sapienza Universitá di Roma, Piazzale A. Moro 2, I-00185 Roma, Italy
| | - Emanuela Zaccarelli
- CNR-ISC Uos Sapienza, Piazzale A. Moro 2, I-00185 Roma, Italy and Dipartimento di Fisica, Sapienza Universitá di Roma, Piazzale A. Moro 2, I-00185 Roma, Italy
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46
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47
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Palberg T. Crystallization kinetics of colloidal model suspensions: recent achievements and new perspectives. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:333101. [PMID: 25035303 DOI: 10.1088/0953-8984/26/33/333101] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Colloidal model systems allow studying crystallization kinetics under fairly ideal conditions, with rather well-characterized pair interactions and minimized external influences. In complementary approaches experiment, analytic theory and simulation have been employed to study colloidal solidification in great detail. These studies were based on advanced optical methods, careful system characterization and sophisticated numerical methods. Over the last decade, both the effects of the type, strength and range of the pair-interaction between the colloidal particles and those of the colloid-specific polydispersity have been addressed in a quantitative way. Key parameters of crystallization have been derived and compared to those of metal systems. These systematic investigations significantly contributed to an enhanced understanding of the crystallization processes in general. Further, new fundamental questions have arisen and (partially) been solved over the last decade: including, for example, a two-step nucleation mechanism in homogeneous nucleation, choice of the crystallization pathway, or the subtle interplay of boundary conditions in heterogeneous nucleation. On the other hand, via the application of both gradients and external fields the competition between different nucleation and growth modes can be controlled and the resulting microstructure be influenced. The present review attempts to cover the interesting developments that have occurred since the turn of the millennium and to identify important novel trends, with particular focus on experimental aspects.
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Affiliation(s)
- Thomas Palberg
- Institut für Physik, Johannes Gutenberg Universität Mainz, 55099 Mainz, Germany
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Franke M, Golde S, Schöpe HJ. Solidification of a colloidal hard sphere like model system approaching and crossing the glass transition. SOFT MATTER 2014; 10:5380-5389. [PMID: 24926966 DOI: 10.1039/c4sm00653d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We investigated the process of vitrification and crystallization in a model system of colloidal hard spheres. The kinetics of the solidification process was measured using time resolved static light scattering, while the time evolution of the dynamic properties was determined using time resolved dynamic light scattering. By performing further analysis we confirm that solidification of hard sphere colloids is mediated by precursors. Analyzing the dynamic properties we can show that the long time dynamics and thus the shear rigidity of the metastable melt is highly correlated with the number density of solid clusters (precursors) nucleated. In crystallization these objects convert into highly ordered crystals whereas in the case of vitrification this conversion is blocked and the system is (temporarily) locked in the metastable precursor state. From the early stages of solidification one cannot clearly conclude whether the melt will crystallize or vitrify. Furthermore our data suggests that colloidal hard sphere glasses can crystallize via homogeneous nucleation.
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Affiliation(s)
- Markus Franke
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
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Sánchez-Díaz LE, Lázaro-Lázaro E, Olais-Govea JM, Medina-Noyola M. Non-equilibrium dynamics of glass-forming liquid mixtures. J Chem Phys 2014; 140:234501. [DOI: 10.1063/1.4882356] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Burger S, Bartsch E. Influence of the polymer size on depletion attraction—induced gel and glass transitions of microgel colloids. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2013.05.060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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