1
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Nouri B, Chen CY, Lin JM, Chen HL. Phase Control of Colloid-like Block Copolymer Micelles by Tuning Size Distribution via Thermal Processing. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Babak Nouri
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chun-Yu Chen
- Experimental Facility Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Jhih-Min Lin
- Experimental Facility Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Hsin-Lung Chen
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
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2
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Singh PK, Pacholski ML, Gu J, Go YK, Singhal G, Leal C, Braun PV, Patankar KA, Drumright R, Rogers SA, Schroeder CM. Designing Multicomponent Polymer Colloids for Self-Stratifying Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11160-11170. [PMID: 36053575 DOI: 10.1021/acs.langmuir.2c00855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Aqueous polymer colloids known as latexes are widely used in coating applications. Multicomponent latexes comprised of two incompatible polymeric species organized into a core-shell particle morphology are a promising system for self-stratifying coatings that spontaneously partition into multiple layers, thereby yielding complex structured coatings requiring only a single application step. Developing new materials for self-stratifying coatings requires a clear understanding of the thermodynamic and kinetic properties governing phase separation and polymeric species transport. In this work, we study phase separation and self-stratification in polymer films based on multicomponent acrylic (shell) and acrylic-silicone (core) latex particles. Our results show that the molecular weight of the shell polymer and heat aging conditions of the film critically determine the underlying transport phenomena, which ultimately controls phase separation in the film. Unentangled shell polymers result in efficient phase separation within hours with heat aging at reasonable temperatures, whereas entangled shell polymers effectively inhibit phase separation even under extensive heat aging conditions over a period of months due to kinetic limitations. Transmission electron microscopy is used to track morphological changes as a function of thermal aging. Interestingly, our results show that the rheological properties of the latex films are highly sensitive to morphology, and linear shear rheology is used to understand morphological changes. Overall, these results highlight the importance of bulk rheology as a simple and effective tool for understanding changes in morphology in multicomponent latex films.
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Affiliation(s)
| | | | - Junsi Gu
- The Dow Chemical Company, Collegeville, Pennsylvania 19426-2914, United States
| | | | | | | | | | | | - Ray Drumright
- The Dow Chemical Company, Midland, Michigan 48667, United States
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3
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Carugno G, Neri I, Vivo P. Instabilities of complex fluids with partially structured and partially random interactions. Phys Biol 2022; 19. [PMID: 35172289 DOI: 10.1088/1478-3975/ac55f9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 02/16/2022] [Indexed: 11/12/2022]
Abstract
We develop a theory for thermodynamic instabilities of complex fluids composed of many interacting chemical species organised in families. This model includes partially structured and partially random interactions and can be solved exactly using tools from random matrix theory. The model exhibits three kinds of fluid instabilities: one in which the species form a condensate with a local density that depends on their family (family condensation); one in which species demix in two phases depending on their family (family demixing); and one in which species demix in a random manner irrespective of their family (random demixing). We determine the critical spinodal density of the three types of instabilities and find that the critical spinodal density is finite for both family condensation and family demixing, while for random demixing the critical spinodal density grows as the square root of the number of species. We use the developed framework to describe phase-separation instability of the cytoplasm induced by a change in pH.
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Affiliation(s)
- Giorgio Carugno
- Mathematics, King's College London, Strand, London, WC2R 2LS, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Izaak Neri
- Mathematics, King's College London, Strand, London, WC2R 2LS, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Pierpaolo Vivo
- King's College London School of Natural and Mathematical Sciences, Strand, London, WC2R 2LS, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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4
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Huang DE, Zia RN. Toward a flow-dependent phase-stability criterion: Osmotic pressure in sticky flowing suspensions. J Chem Phys 2021; 155:134113. [PMID: 34624990 DOI: 10.1063/5.0058676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Equilibrium phase instability of colloids is robustly predicted by the Vliegenthart-Lekkerkerker (VL) critical value of the second virial efficient, but no such general criterion has been established for suspensions undergoing flow. A transition from positive to negative osmotic pressure is one mechanical hallmark of a change in phase stability in suspensions and provides a natural extension of the equilibrium osmotic pressure encoded in the second virial coefficient. Here, we propose to study the non-Newtonian rheology of an attractive colloidal suspension using the active microrheology framework as a model for focusing on the pair trajectories that underlie flow stability. We formulate and solve a Smoluchowski relation to understand the interplay between attractions, hydrodynamics, Brownian motion, and flow on particle microstructure in a semi-dilute suspension and utilize the results to study the viscosity and particle-phase osmotic pressure. We find that an interplay between attractions and hydrodynamics leads to dramatic changes in the nonequilibrium microstructure, which produces a two-stage flow-thinning of viscosity and leads to pronounced flow-induced negative osmotic pressure. We summarize these findings with an osmotic pressure heat map that predicts where hydrodynamic enhancement of attractive bonds encourages flow-induced aggregation or phase separation. We identify a critical isobar-a flow-induced critical pressure consistent with phase instability and a nonequilibrium extension of the VL criterion.
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Affiliation(s)
- Derek E Huang
- Department of Chemical Engineering, Stanford University, Stanford, California 94302, USA
| | - Roseanna N Zia
- Department of Chemical Engineering, Stanford University, Stanford, California 94302, USA
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5
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Yao LD, Chen HY, Shi Y, Liang Y, Zhang TH. Synchronized fractionation and phase separation in binary colloids. SOFT MATTER 2020; 16:9042-9046. [PMID: 32914805 DOI: 10.1039/d0sm00751j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Fractionation is necessary for self-assembly in multicomponent mixtures. Here, reversible fractionation and crystallization are realized and studied in two-dimensional binary colloids which are supersaturated by enhancing the attraction between colloidal particles. As a deep and fast supersaturation results in gels with a uniform distribution of binary particles, a gradual quasistatic supersaturation process leads to a two-step crystallization in which small particles and large particles are fractionated as coexisting crystal and liquid phases respectively. Fractionation occurs as well in the quasistatic melting of gels. We show that the synchronized fractionation and phase separation arises from the competition between the size-dependent repulsion and the tunable attraction. The results in this study demonstrate a robust mechanism of fractionation via phase separation, and have important implication in understanding the reversible formation of membraneless organelles in living cells.
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Affiliation(s)
- Lian Dan Yao
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou, 215006, P. R. China.
| | - Hong Yu Chen
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou, 215006, P. R. China.
| | - Yan Shi
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou, 215006, P. R. China.
| | - Ying Liang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou, 215006, P. R. China.
| | - Tian Hui Zhang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou, 215006, P. R. China. and School of Physical Science and Technology, Soochow University, Suzhou, 215006, P. R. China
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6
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Schaertl N, Botin D, Palberg T, Bartsch E. Formation of Laves phases in buoyancy matched hard sphere suspensions. SOFT MATTER 2018; 14:5130-5139. [PMID: 29881859 DOI: 10.1039/c7sm02348k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Colloidal Laves phases (LPs) are promising precursors for photonic materials. Laves phases have not yet been observed to form in experiments on colloidal suspensions of hard spheres (HS), even though they have been reported in computer simulations. LP formation so far has been achieved only for binary mixtures of colloidal charged spheres or ligand-stabilized nano-particles after drying. Using static light scattering, we monitored LP formation and annealing in a binary mixture of buoyant hard sphere approximants (size ratio Γ = 0.77, number or molar fraction of small spheres xS = 0.76) for volume fractions in the fluid-crystal coexistence regions. All samples spontaneously formed MgZn2 type LPs on the time scale of weeks to months via bulk nucleation and growth. Irrespective of the initial suspension volume fractions, the LP volume fraction at coexistence is ΦCOEX = 0.59 which is significantly below the close packing limit ΦMAX = 0.615 and remarkably close to the expectation from simulation. At low volume fractions, crystals anneal to high quality during coarsening which is in line with recent theoretical expectations for the thermodynamic stability of different LP types. At large volume fractions, however, the diffractograms evolve towards a more MgCu2-like appearance which we attribute to the formation of randomly stacked LPs. Such structures are not known from atomic systems.
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Affiliation(s)
- N Schaertl
- Institut für Makromolekulare Chemie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany.
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7
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Lindquist BA, Jadrich RB, Truskett TM. Communication: From close-packed to topologically close-packed: Formation of Laves phases in moderately polydisperse hard-sphere mixtures. J Chem Phys 2018; 148:191101. [DOI: 10.1063/1.5028279] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Beth A. Lindquist
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712,
USA
| | - Ryan B. Jadrich
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712,
USA
| | - Thomas M. Truskett
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712,
USA
- Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA
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8
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Heckendorf D, Mutch KJ, Egelhaaf SU, Laurati M. Size-Dependent Localization in Polydisperse Colloidal Glasses. PHYSICAL REVIEW LETTERS 2017; 119:048003. [PMID: 29341743 DOI: 10.1103/physrevlett.119.048003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Indexed: 06/07/2023]
Abstract
We have investigated concentrated suspensions of polydisperse hard spheres and have determined the dynamics and sizes of individual particles using confocal microscopy. With increasing concentration, the dynamics of the small and large particles start to differ. The large particles exhibit slower dynamics and stronger localization. Moreover, as the particle size increases, the local volume fraction ϕ_{loc} also increases. In the glass state, the localization length significantly decreases beyond ϕ_{loc}≈0.67. This suggests a link between local crowding and dynamical heterogeneities. However dynamical arrest of subpopulations seems not directly linked to a large value of ϕ_{loc}, indicating the importance of collective effects.
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Affiliation(s)
- D Heckendorf
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - K J Mutch
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - S U Egelhaaf
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - M Laurati
- Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico
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9
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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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10
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de Castro P, Sollich P. Phase separation dynamics of polydisperse colloids: a mean-field lattice-gas theory. Phys Chem Chem Phys 2017; 19:22509-22527. [DOI: 10.1039/c7cp04062h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Strong theoretical evidence shows that dense colloidal mixtures phase-separate in two stages and the denser phase contains long-lived composition heterogeneities.
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Affiliation(s)
- Pablo de Castro
- Disordered Systems Group
- Department of Mathematics
- King's College London
- London
- UK
| | - Peter Sollich
- Disordered Systems Group
- Department of Mathematics
- King's College London
- London
- UK
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11
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Herlach DM, Palberg T, Klassen I, Klein S, Kobold R. Overview: Experimental studies of crystal nucleation: Metals and colloids. J Chem Phys 2016; 145:211703. [DOI: 10.1063/1.4963684] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Dieter M. Herlach
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
| | - Thomas Palberg
- Institut für Physik, Johannes Gutenberg Universität Mainz, 55099 Mainz, Germany
| | - Ina Klassen
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
- Projektträger Jülich, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Stefan Klein
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
| | - Raphael Kobold
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
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12
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Hwang J, Kim J, Sung BJ. Dynamics of highly polydisperse colloidal suspensions as a model system for bacterial cytoplasm. Phys Rev E 2016; 94:022614. [PMID: 27627367 DOI: 10.1103/physreve.94.022614] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Indexed: 11/07/2022]
Abstract
There are various kinds of macromolecules in bacterial cell cytoplasm. The size polydispersity of the macromolecules is so significant that the crystallization and the phase separation could be suppressed, thus stabilizing the liquid state of bacterial cytoplasm. On the other hand, recent experiments suggested that the macromolecules in bacterial cytoplasm should exhibit glassy dynamics, which should be also affected significantly by the size polydispersity of the macromolecules. In this work, we investigate the anomalous and slow dynamics of highly polydisperse colloidal suspensions, of which size distribution is chosen to mimic Escherichia coli cytoplasm. We find from our Langevin dynamics simulations that the diffusion coefficient (D_{tot}) and the displacement distribution functions (P(r,t)) averaged over all colloids of different sizes do not show anomalous and glassy dynamic behaviors until the system volume fraction ϕ is increased up to 0.82. This indicates that the intrinsic polydispersity of bacterial cytoplasm should suppress the glass transition and help maintain the liquid state of the cytoplasm. On the other hand, colloids of each kind show totally different dynamic behaviors depending on their size. The dynamics of colloids of different size becomes non-Gaussian at a different range of ϕ, which suggests that a multistep glass transition should occur. The largest colloids undergo the glass transition at ϕ=0.65, while the glass transition does not occur for smaller colloids in our simulations even at the highest value of ϕ. We also investigate the distribution (P(θ,t)) of the relative angles of displacement for macromolecules and find that macromolecules undergo directionally correlated motions in a sufficiently dense system.
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Affiliation(s)
- Jiye Hwang
- Department of Chemistry, Sogang University, Seoul 121-742, Republic of Korea
| | - Jeongmin Kim
- Department of Chemistry, Sogang University, Seoul 121-742, Republic of Korea
| | - Bong June Sung
- Department of Chemistry, Sogang University, Seoul 121-742, Republic of Korea
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13
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Palberg T, Wette P, Herlach DM. Equilibrium fluid-crystal interfacial free energy of bcc-crystallizing aqueous suspensions of polydisperse charged spheres. Phys Rev E 2016; 93:022601. [PMID: 26986371 DOI: 10.1103/physreve.93.022601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Indexed: 06/05/2023]
Abstract
The interfacial free energy is a central quantity in crystallization from the metastable melt. In suspensions of charged colloidal spheres, nucleation and growth kinetics can be accurately measured from optical experiments. In previous work, from these data effective nonequilibrium values for the interfacial free energy between the emerging bcc nuclei and the adjacent melt in dependence on the chemical potential difference between melt phase and crystal phase were derived using classical nucleation theory (CNT). A strictly linear increase of the interfacial free energy was observed as a function of increased metastability. Here, we further analyze these data for five aqueous suspensions of charged spheres and one binary mixture. We utilize a simple extrapolation scheme and interpret our findings in view of Turnbull's empirical rule. This enables us to present the first systematic experimental estimates for a reduced interfacial free energy, σ(0,bcc), between the bcc-crystal phase and the coexisting equilibrium fluid. Values obtained for σ(0,bcc) are on the order of a few k(B)T. Their values are not correlated to any of the electrostatic interaction parameters but rather show a systematic decrease with increasing size polydispersity and a lower value for the mixture as compared to the pure components. At the same time, σ(0) also shows an approximately linear correlation to the entropy of freezing. The equilibrium interfacial free energy of strictly monodisperse charged spheres may therefore be still greater.
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Affiliation(s)
- Thomas Palberg
- Institut für Physik, Johannes Gutenberg Universität Mainz, 55099 Mainz, Germany
| | - Patrick Wette
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51147 Köln, Germany
- Space Administration, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 53227 Bonn, Germany
| | - Dieter M Herlach
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51147 Köln, Germany
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14
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Karmakar S, Dasgupta C, Sastry S. Length scales in glass-forming liquids and related systems: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:016601. [PMID: 26684508 DOI: 10.1088/0034-4885/79/1/016601] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The central problem in the study of glass-forming liquids and other glassy systems is the understanding of the complex structural relaxation and rapid growth of relaxation times seen on approaching the glass transition. A central conceptual question is whether one can identify one or more growing length scale(s) associated with this behavior. Given the diversity of molecular glass-formers and a vast body of experimental, computational and theoretical work addressing glassy behavior, a number of ideas and observations pertaining to growing length scales have been presented over the past few decades, but there is as yet no consensus view on this question. In this review, we will summarize the salient results and the state of our understanding of length scales associated with dynamical slow down. After a review of slow dynamics and the glass transition, pertinent theories of the glass transition will be summarized and a survey of ideas relating to length scales in glassy systems will be presented. A number of studies have focused on the emergence of preferred packing arrangements and discussed their role in glassy dynamics. More recently, a central object of attention has been the study of spatially correlated, heterogeneous dynamics and the associated length scale, studied in computer simulations and theoretical analysis such as inhomogeneous mode coupling theory. A number of static length scales have been proposed and studied recently, such as the mosaic length scale discussed in the random first-order transition theory and the related point-to-set correlation length. We will discuss these, elaborating on key results, along with a critical appraisal of the state of the art. Finally we will discuss length scales in driven soft matter, granular fluids and amorphous solids, and give a brief description of length scales in aging systems. Possible relations of these length scales with those in glass-forming liquids will be discussed.
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Affiliation(s)
- Smarajit Karmakar
- TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad 500075, India
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15
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Beyer R, Franke M, Schöpe HJ, Bartsch E, Palberg T. From nuclei to micro-structure in colloidal crystallization: Investigating intermediate length scales by small angle laser light scattering. J Chem Phys 2015; 143:064903. [DOI: 10.1063/1.4928370] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Richard Beyer
- Institut für Physik, Johannes Gutenberg Universität, D-55099 Mainz, Germany
| | - Markus Franke
- Institut für Physik, Johannes Gutenberg Universität, D-55099 Mainz, Germany
| | | | - Eckhard Bartsch
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität, D-79104 Freiburg, Germany
| | - Thomas Palberg
- Institut für Physik, Johannes Gutenberg Universität, D-55099 Mainz, Germany
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16
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Zhang TH, Kuipers BWM, Tian WD, Groenewold J, Kegel WK. Polydispersity and gelation in concentrated colloids with competing interactions. SOFT MATTER 2015; 11:297-302. [PMID: 25407503 DOI: 10.1039/c4sm02273d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In colloids with competing short-range attractions and long-range repulsions, microcrystalline gels are experimentally formed under conditions where computer simulations point to a lamellar phase as the ground state. Here, upon applying a low-frequency alternating electric field, we bring the system from an initial gel state to a columnar-like state. While molecular dynamics simulations on monodisperse colloids reveal that a columnar structure spontaneously evolves towards a lamellar phase, the columnar-like state in experiments relaxes back to the initial disordered gel state once the electric field is switched off. Similarly, a columnar phase in molecular dynamics simulations decomposes into finite-size crystalline clusters as the relative polydispersity of the colloids is around 1.0%. We conclude that the experimentally observed melting of the columnar structure is driven by polydispersity. Moreover, further simulations reveal that the critical polydispersity required to destabilize a long-range ordered structure increases with the attraction range, pointing to the possibility of observing periodic structures in experiments if the attraction range is sufficiently long compared to the polydispersity of the colloids.
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Affiliation(s)
- Tian Hui Zhang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou, 215006, P. R. China.
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17
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Kozina A, Díaz-Leyva P, Palberg T, Bartsch E. Crystallization kinetics of colloidal binary mixtures with depletion attraction. SOFT MATTER 2014; 10:9523-9533. [PMID: 25354340 DOI: 10.1039/c4sm02193b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this work the crystallization kinetics of colloidal binary mixtures with attractive interaction potential (Asakura-Oosawa) has been addressed. Parameters such as fraction of crystals, linear crystal dimension and crystal packing have been quantified in order to understand how the crystal formation is driven in terms of the depth of the attractive potential and the composition of the binary mixture (described by the number ratio). It was found that inside the eutectic triangle, crystallization is mainly governed by nucleation and the crystal packing is close to the close-packing of hard spheres. Moving out from the eutectic triangle towards small component results in the crystallization of small spheres. Enrichment of the eutectic mixture with large component results in the crystallization of both large and small spheres, however, the kinetics are completely different from those of the eutectic composition. Crosslinked polystyrene microgels with nearly hard sphere interactions were used as model systems. Attraction was introduced by addition of linear polystyrene. The time evolution of crystallization has been followed by static light scattering.
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Affiliation(s)
- Anna Kozina
- Institut für Makromolekulare Chemie, Albert-Ludwigs-Universität Freiburg, Stefan-Meier-Str. 31, 79104 Freiburg, Germany.
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18
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Williamson JJ, Evans RML. Measuring local volume fraction, long-wavelength correlations, and fractionation in a phase-separating polydisperse fluid. J Chem Phys 2014; 141:164901. [PMID: 25362335 DOI: 10.1063/1.4897560] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- J. J. Williamson
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets, N.W., Washington, D.C. 20057, USA
| | - R. M. L. Evans
- School of Mathematics, University of Leeds, Leeds LS2 9JT, United Kingdom
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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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20
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Blanco MA, Sahin E, Robinson AS, Roberts CJ. Coarse-grained model for colloidal protein interactions, B(22), and protein cluster formation. J Phys Chem B 2013; 117:16013-28. [PMID: 24289039 DOI: 10.1021/jp409300j] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Reversible protein cluster formation is an important initial step in the processes of native and non-native protein aggregation, but involves relatively long time and length scales for detailed atomistic simulations and extensive mapping of free energy landscapes. A coarse-grained (CG) model is presented to semiquantitatively characterize the thermodynamics and key configurations involved in the landscape for protein oligomerization, as well as experimental measures of interactions such as the osmotic second virial coefficient (B22). Based on earlier work (Grüenberger et al., J. Phys. Chem. B 2013, 117, 763), this CG model treats proteins as rigid bodies composed of one bead per amino acid, with each amino acid having specific parameters for its size, hydrophobicity, and charge. The net interactions are a combination of steric repulsions, short-range attractions, and screened long-range charge-charge interactions. Model parametrization was done by fitting simulation results against experimental value of B22 as a function of solution ionic strength for α-chymotrypsinogen A and γD-Crystallin (gD-Crys). The CG model is applied to characterize the pairwise interactions and dimerization of gD-Crys and the dependence on temperature, protein concentration, and ionic strength. The results illustrate that at experimentally relevant conditions where stable dimers do not form, the entropic contributions are predominant in the free-energy of protein cluster formation and colloidal protein interactions, arguing against interpretations that treat B22 primarily from energetic considerations alone. Additionally, the results suggest that electrostatic interactions help to modulate the population of the different stable configurations for protein nearest-neighbor pairs, while short-range attractions determine the relative orientations of proteins within these configurations. Finally, simulation results are combined with Principal Component Analysis to identify those amino-acids/surface patches that form interprotein contacts at conditions that favor dimerization of gD-Crys. The resulting regions agree with previously found aggregation-prone sites, as well as suggesting new ones that may be important.
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Affiliation(s)
- Marco A Blanco
- Department of Chemical and Biomolecular Engineering and Center for Molecular and Engineering Thermodynamics, University of Delaware , Newark, Delaware 19176, United States
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21
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Jacobs WM, Frenkel D. Predicting phase behavior in multicomponent mixtures. J Chem Phys 2013; 139:024108. [DOI: 10.1063/1.4812461] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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22
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Leocmach M, Russo J, Tanaka H. Importance of many-body correlations in glass transition: An example from polydisperse hard spheres. J Chem Phys 2013; 138:12A536. [DOI: 10.1063/1.4769981] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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van der Linden MN, van Blaaderen A, Dijkstra M. Effect of size polydispersity on the crystal-fluid and crystal-glass transition in hard-core repulsive Yukawa systems. J Chem Phys 2013; 138:114903. [DOI: 10.1063/1.4794918] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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24
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Wiemann M, Willenbacher N, Bartsch E. Effect of cross-link density on re-entrant melting of microgel colloids. Colloids Surf A Physicochem Eng Asp 2012. [DOI: 10.1016/j.colsurfa.2011.11.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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25
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Williamson JJ, Evans RML. Spinodal fractionation in a polydisperse square-well fluid. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:011405. [PMID: 23005415 DOI: 10.1103/physreve.86.011405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Indexed: 06/01/2023]
Abstract
Using kinetic Monte Carlo simulation, we model gas-liquid spinodal decomposition in a size-polydisperse square well fluid, representing a "near-monodisperse" colloidal dispersion. We find that fractionation (demixing) of particle sizes between the phases begins asserting itself shortly after the onset of phase ordering. Strikingly, the direction of size fractionation can be reversed by a seemingly trivial choice between two interparticle potentials which, in the monodisperse case, are identical--we rationalize this in terms of a perturbative, equilibrium theory of polydispersity. Furthermore, our quantitative results show that kinetic Monte Carlo simulation can provide detailed insight into the role of fractionation in real colloidal systems.
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Affiliation(s)
- J J Williamson
- Soft Matter Group, School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, England, United Kingdom
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26
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Ogarko V, Luding S. Equation of state and jamming density for equivalent bi- and polydisperse, smooth, hard sphere systems. J Chem Phys 2012; 136:124508. [DOI: 10.1063/1.3694030] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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27
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von der Heydt A, Müller M, Zippelius A. Three-phase coexistence with sequence partitioning in symmetric random block copolymers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:051131. [PMID: 21728514 DOI: 10.1103/physreve.83.051131] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 01/10/2011] [Indexed: 05/31/2023]
Abstract
We inquire into the possible coexistence of macroscopic and microstructured phases in random Q-block copolymers built of incompatible monomer types A and B with equal average concentrations. In our microscopic model, one block comprises M identical monomers. The block-type sequence distribution is Markovian and characterized by the correlation λ. Upon increasing the incompatibility χ (by decreasing temperature) in the disordered state, the known ordered phases form: for λ>λ(c), two coexisting macroscopic A- and B-rich phases, for λ<λ(c), a microstructured (lamellar) phase with wave number k(λ). In addition, we find a fourth region in the λ-χ plane where these three phases coexist, with different, non-Markovian sequence distributions (fractionation). Fractionation is revealed by our analytically derived multiphase free energy, which explicitly accounts for the exchange of individual sequences between the coexisting phases. The three-phase region is reached, either from the macroscopic phases, via a third lamellar phase that is rich in alternating sequences, or, starting from the lamellar state, via two additional homogeneous, homopolymer-enriched phases. These incipient phases emerge with zero volume fraction. The four regions of the phase diagram meet in a multicritical point (λ(c),χ(c)), at which A-B segregation vanishes. The analytical method, which for the lamellar phase assumes weak segregation, thus proves reliable particularly in the vicinity of (λ(c),χ(c)). For random triblock copolymers, Q=3, we find the character of this point and the critical exponents to change substantially with the number M of monomers per block. The results for Q=3 in the continuous-chain limit M→∞ are compared to numerical self-consistent field theory (SCFT), which is accurate at larger segregation.
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Affiliation(s)
- Alice von der Heydt
- Institut für Theoretische Physik, Georg-August-Universität Göttingen, Göttingen, Germany.
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28
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Colombo J, Dijkstra M. Effect of quenched size polydispersity on the fluid-solid transition in charged colloidal suspensions. J Chem Phys 2011; 134:154504. [DOI: 10.1063/1.3580284] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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29
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Filion L, Hermes M, Ni R, Dijkstra M. Crystal nucleation of hard spheres using molecular dynamics, umbrella sampling, and forward flux sampling: A comparison of simulation techniques. J Chem Phys 2010; 133:244115. [DOI: 10.1063/1.3506838] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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30
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Wilding NB, Sollich P. Phase behavior of polydisperse spheres: Simulation strategies and an application to the freezing transition. J Chem Phys 2010; 133:224102. [DOI: 10.1063/1.3510534] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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31
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Yiannourakou M, Economou IG, Bitsanis IA. Structural and dynamical analysis of monodisperse and polydisperse colloidal systems. J Chem Phys 2010; 133:224901. [DOI: 10.1063/1.3506576] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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Martinez VA, Bryant G, van Megen W. Aging dynamics of colloidal hard sphere glasses. J Chem Phys 2010; 133:114906. [DOI: 10.1063/1.3478542] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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33
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Fernández LA, Martín-Mayor V, Seoane B, Verrocchio P. Separation and fractionation of order and disorder in highly polydisperse systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:021501. [PMID: 20866812 DOI: 10.1103/physreve.82.021501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 05/07/2010] [Indexed: 05/29/2023]
Abstract
We study a polydisperse soft-spheres model for colloids by means of microcanonical Monte Carlo simulations. We consider a polydispersity as high as 24%. Although solidification occurs, neither a crystal nor an amorphous state are thermodynamically stable. A finite size scaling analysis reveals that in the thermodynamic limit: (a) the fluid-solid transition is rather a crystal-amorphous phase-separation, (b) such phase-separation is preceded by the dynamic glass transition, and (c) small and big particles arrange themselves in the two phases according to a complex pattern not predicted by any fractionation scenario.
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Affiliation(s)
- L A Fernández
- Departamento de Física Teórica I, Universidad Complutense, Madrid, Spain
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34
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Kurita R, Weeks ER. Experimental study of random-close-packed colloidal particles. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:011403. [PMID: 20866616 DOI: 10.1103/physreve.82.011403] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2010] [Indexed: 05/29/2023]
Abstract
A collection of spherical particles can be packed tightly together into an amorphous packing known as "random close packing" (RCP). This structure is of interest as a model for the arrangement of molecules in simple liquids and glasses, as well as the arrangement of particles in sand piles. We use confocal microscopy to study the arrangement of colloidal particles in an experimentally realized RCP state. We image a large volume containing more than 450,000 particles with a resolution of each particle position to better than 0.02 particle diameters. While the arrangement of the particles satisfies multiple criteria for being random, we also observe a small fraction (less than 3%) of tiny crystallites (4 particles or fewer). These regions pack slightly better and are thus associated with locally higher densities. The structure factor of our sample at long length scales is nonzero, S(0)=0.049±0.008, suggesting that there are long wavelength density fluctuations in our sample. These may be due to polydispersity or tiny crystallites. Our results suggest that experimentally realizable RCP systems may be different from simulated RCP systems, in particular, with the presence of these long wavelength density fluctuations.
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Affiliation(s)
- Rei Kurita
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
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35
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Kawasaki T, Tanaka H. Structural origin of dynamic heterogeneity in three-dimensional colloidal glass formers and its link to crystal nucleation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:232102. [PMID: 21393759 DOI: 10.1088/0953-8984/22/23/232102] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The physical understanding of glass transition remains a major challenge of physics and materials science. Among various glass-forming liquids, a colloidal liquid interacting with hard-core repulsion is now regarded as one of the most ideal model systems. Here we study the structure and dynamics of three-dimensional polydisperse colloidal liquids by Brownian dynamics simulations. We reveal that medium-range crystalline bond orientational order of the hexagonal close packed structure grows in size and lifetime with increasing packing fraction. We show that dynamic heterogeneity may be a direct consequence of this transient structural ordering, which suggests its origin is thermodynamic rather than kinetic. We also reveal that nucleation of crystals preferentially occurs in regions of high medium-range order, reflecting the low crystal-liquid interfacial energy there. These findings may shed new light not only on the fundamental nature of the glass transition, but also the mechanism of crystal nucleation.
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Affiliation(s)
- Takeshi Kawasaki
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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36
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Byelov DV, Mourad MCD, Snigireva I, Snigirev A, Petukhov AV, Lekkerkerker HNW. Experimental observation of fractionated crystallization in polydisperse platelike colloids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:6898-6901. [PMID: 20392119 DOI: 10.1021/la100993k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We have discovered that the long-term aging of the hexagonal columnar liquid-crystal phase of polydisperse gibbsite platelets leads to fractionated crystallization, that is, to the formation of coexisting columnar crystals with different periods. This process was revealed by microradian X-ray diffraction demonstrating the splitting of the Bragg intercolumnar reflections into sequences of sharper reflections. The fractionated crystallization was observed in a number of samples of sterically stabilized as well as charge-stabilized polydisperse gibbsite platelets.
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Affiliation(s)
- D V Byelov
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands.
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37
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Sollich P, Wilding NB. Crystalline phases of polydisperse spheres. PHYSICAL REVIEW LETTERS 2010; 104:118302. [PMID: 20366504 DOI: 10.1103/physrevlett.104.118302] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Indexed: 05/29/2023]
Abstract
We use specialized Monte Carlo simulation methods and moment free energy calculations to provide conclusive evidence that dense polydisperse spheres at equilibrium demix into coexisting fcc phases, with more phases appearing as the spread of diameters increases. We manage to track up to four coexisting phases. Each of these is fractionated: it contains a narrower distribution of particle sizes than is present in the system overall. We also demonstrate that, surprisingly, demixing transitions can be nearly continuous, accompanied by fluctuations in local particle size correlated over many lattice spacings.
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Affiliation(s)
- Peter Sollich
- King's College London, Department of Mathematics, Strand, London WC2R 2LS, United Kingdom
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38
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Hermes M, Dijkstra M. Thermodynamic signature of the dynamic glass transition in hard spheres. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:104114. [PMID: 21389448 DOI: 10.1088/0953-8984/22/10/104114] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We use extensive event-driven molecular dynamics simulations to study the thermodynamic, structural and dynamic properties of hard-sphere glasses. We determine the equation of state of the metastable fluid branch for hard spheres with a size polydispersity of 10%. Our results show a clear jump in the slope of the isothermal compressibility. The observation of a thermodynamic signature at the transition from a metastable fluid to a glassy state is analogous to the abrupt change in the specific heat or thermal expansion coefficient as observed for molecular liquids at the glass transition. The dynamic glass transition becomes more pronounced and shifts to higher densities for longer equilibration times.
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Affiliation(s)
- Michiel Hermes
- Soft Condensed Matter Group, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
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39
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Pusey PN, Zaccarelli E, Valeriani C, Sanz E, Poon WCK, Cates ME. Hard spheres: crystallization and glass formation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2009; 367:4993-5011. [PMID: 19933124 DOI: 10.1098/rsta.2009.0181] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Motivated by old experiments on colloidal suspensions, we report molecular dynamics simulations of assemblies of hard spheres, addressing crystallization and glass formation. The simulations cover wide ranges of polydispersity s (standard deviation of the particle size distribution divided by its mean) and particle concentration. No crystallization is observed for s>0.07. For 0.02<s<0.07, we find that increasing the polydispersity at a given concentration slows down crystal nucleation. The main effect here is that polydispersity reduces the supersaturation since it tends to stabilize the fluid but to destabilize the crystal. At a given polydispersity (<0.07), we find three regimes of nucleation: standard nucleation and growth at concentrations in and slightly above the coexistence region; 'spinodal nucleation', where the free-energy barrier to nucleation appears to be negligible, at intermediate concentrations; and, at the highest concentrations, a new mechanism, still to be fully understood, which only requires small rearrangement of the particle positions. The cross-over between the second and third regimes occurs at a concentration, approximately 58 per cent by volume, where the colloid experiments show a marked change in the nature of the crystals formed and the particle dynamics indicate an 'ideal' glass transition.
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Affiliation(s)
- P N Pusey
- SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK.
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40
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Yiannourakou M, Economou IG, Bitsanis IA. Phase equilibrium of colloidal suspensions with particle size dispersity: A Monte Carlo study. J Chem Phys 2009; 130:194902. [DOI: 10.1063/1.3131691] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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41
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Wilding NB. Solid-liquid coexistence of polydisperse fluids via simulation. J Chem Phys 2009; 130:104103. [DOI: 10.1063/1.3081141] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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42
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Iacopini S, Palberg T, Schöpe HJ. Crystallization kinetics of polydisperse hard-sphere-like microgel colloids: Ripening dominated crystal growth above melting. J Chem Phys 2009; 130:084502. [DOI: 10.1063/1.3078310] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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43
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Iacopini S, Palberg T, Schöpe HJ. Ripening-dominated crystallization in polydisperse hard-sphere-like colloids. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:010601. [PMID: 19256993 DOI: 10.1103/physreve.79.010601] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 11/06/2008] [Indexed: 05/27/2023]
Abstract
We report on the crystal growth scenario in gravity-matched, polydisperse hard-sphere-like colloids at increasing particle concentration. In the fluid-crystal coexistence region, the crystal size as a function of time shows two separate regimes corresponding to crystal growth and crystal ripening. At higher supersaturation the crystal size grows according to the same power law through the whole experimental window of a few days: crystal growth and ripening merge together. We show that our observations cannot be explained by considering the slowing down of single-particle dynamics due to increasing volume fraction. We suggest that size fractionation occurring at the crystal-fluid interface is the dominant mechanism.
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Affiliation(s)
- Sara Iacopini
- Institut für Physik, Johannes Gutenberg Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
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44
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Norman AI, Manvilla BA, Frank EL, Niamke JN, Smith GD, Greer SC. Partitioning of Poly(ethylene oxide), Poly(ethylene imide), and Bovine Serum Albumin in Isobutyric Acid + Water. Macromolecules 2008. [DOI: 10.1021/ma071711l] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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45
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Schöpe HJ, Bryant G, van Megen W. Effect of polydispersity on the crystallization kinetics of suspensions of colloidal hard spheres when approaching the glass transition. J Chem Phys 2007; 127:084505. [PMID: 17764267 DOI: 10.1063/1.2760207] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a comprehensive study of the solidification scenario in suspensions of colloidal hard spheres for three polydispersities between 4.8% and 5.8%, over a range of volume fractions from near freezing to near the glass transition. From these results, we identify four stages in the crystallization process: (i) an induction stage where large numbers of precursor structures are observed, (ii) a conversion stage as precursors are converted to close packed structures, (iii) a nucleation stage, and (iv) a ripening stage. It is found that the behavior is qualitatively different for volume fractions below or above the melting volume fraction. The main effect of increasing polydispersity is to increase the duration of the induction stage, due to the requirement for local fractionation of particles of larger or smaller than average size. Near the glass transition, the nucleation process is entirely frustrated, and the sample is locked into a compressed crystal precursor structure. Interestingly, neither polydispersity nor volume fraction significantly influences the precursor stage, suggesting that the crystal precursors are present in all solidifying samples. We speculate that these precursors are related to the dynamical heterogeneities observed in a number of dynamical studies.
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Affiliation(s)
- Hans Joachim Schöpe
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
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46
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Fernández LA, Martín-Mayor V, Verrocchio P. Phase diagram of a polydisperse soft-spheres model for liquids and colloids. PHYSICAL REVIEW LETTERS 2007; 98:085702. [PMID: 17359112 DOI: 10.1103/physrevlett.98.085702] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Revised: 12/06/2006] [Indexed: 05/14/2023]
Abstract
The phase diagram of soft spheres with size dispersion is studied by means of an optimized Monte Carlo algorithm which allows us to equilibrate below the kinetic glass transition for all size distributions. The system ubiquitously undergoes a first-order freezing transition. While for a small size dispersion the frozen phase has a crystalline structure, large density inhomogeneities appear in the highly disperse systems. Studying the interplay between the equilibrium phase diagram and the kinetic glass transition, we argue that the experimentally found terminal polydispersity of colloids is a purely kinetic phenomenon.
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Affiliation(s)
- L A Fernández
- Departamento de Física Teórica I, Universidad Complutense, 28040 Madrid, Spain
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47
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Schöpe HJ, Bryant G, van Megen W. Small changes in particle-size distribution dramatically delay and enhance nucleation in hard sphere colloidal suspensions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:060401. [PMID: 17280031 DOI: 10.1103/physreve.74.060401] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Indexed: 05/13/2023]
Abstract
We present hard-sphere crystallization kinetics for three samples with small differences in polydispersity. We show that an increase in polydispersity of 1% is sufficient to cause dramatic changes in the crystallization kinetics: crystallization is delayed by almost one decade in time and quantitative and qualitative changes in the crystallization scenario are observed. Surprisingly the nucleation rate density is enhanced by almost a factor of 10. We interpret these results in terms of polydispersity limited growth, where local fractionation processes lead to a delayed but faster nucleation.
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Affiliation(s)
- Hans Joachim Schöpe
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
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48
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Fantoni R, Gazzillo D, Giacometti A, Sollich P. Phase behavior of weakly polydisperse sticky hard spheres: Perturbation theory for the Percus-Yevick solution. J Chem Phys 2006; 125:164504. [PMID: 17092102 DOI: 10.1063/1.2358136] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We study the effects of size polydispersity on the gas-liquid phase behavior of mixtures of sticky hard spheres. To achieve this, the system of coupled quadratic equations for the contact values of the partial cavity functions of the Percus-Yevick solution [R. J. Baxter, J. Chem. Phys. 49, 2770 (1968)] is solved within a perturbation expansion in the polydispersity, i.e., the normalized width of the size distribution. This allows us to make predictions for various thermodynamic quantities which can be tested against numerical simulations and experiments. In particular, we determine the leading order effects of size polydispersity on the cloud curve delimiting the region of two-phase coexistence and on the associated shadow curve; we also study the extent of size fractionation between the coexisting phases. Different choices for the size dependence of the adhesion strengths are examined carefully; the Asakura-Oosawa model [J. Chem. Phys. 22, 1255 (1954)] of a mixture of polydisperse colloids and small polymers is studied as a specific example.
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Affiliation(s)
- Riccardo Fantoni
- Istituto Nazionale per la Fisica della Materia and Dipartimento di Chimica Fisica, Università Ca' Foscari di Venezia, Santa Marta DD 2137, I-30123 Venezia, Italy.
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Wilding NB, Sollich P, Fasolo M, Buzzacchi M. Phase behavior and particle size cutoff effects in polydisperse fluids. J Chem Phys 2006; 125:014908. [PMID: 16863334 DOI: 10.1063/1.2208358] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We report a joint simulation and theoretical study of the liquid-vapor phase behavior of a fluid in which polydispersity in the particle size couples to the strength of the interparticle interactions. Attention is focused on the case in which the particle diameters are distributed according to a fixed Schulz form with degree of polydispersity delta = 14%. The coexistence properties of this model are studied using grand canonical ensemble Monte Carlo simulations and moment free energy calculations. We obtain the cloud and shadow curves as well as the daughter phase density distributions and fractional volumes along selected isothermal dilution lines. In contrast to the case of size-independent interaction [N. B. Wilding et al., J. Chem. Phys. 121, 6887 (2004)], the cloud and shadow curves are found to be well separated, with the critical point lying significantly below the cloud curve maximum. For densities below the critical value, we observe that the phase behavior is highly sensitive to the choice of upper cutoff on the particle size distribution. We elucidate the origins of this effect in terms of extremely pronounced fractionation effects and discuss the likely appearance of new phases in the limit of very large values of the cutoff.
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Affiliation(s)
- Nigel B Wilding
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom.
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Chaudhuri P, Karmakar S, Dasgupta C, Krishnamurthy HR, Sood AK. Equilibrium glassy phase in a polydisperse hard-sphere system. PHYSICAL REVIEW LETTERS 2005; 95:248301. [PMID: 16384428 DOI: 10.1103/physrevlett.95.248301] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Indexed: 05/05/2023]
Abstract
The phase diagram of a polydisperse hard-sphere system is examined by numerical minimization of a discretized form of the Ramakrishnan-Yussouff free-energy functional. Crystalline and glassy local minima of the free energy are located and the phase diagram in the density-polydispersity plane is mapped out by comparing the free energies of different local minima. The crystalline phase disappears and the glass becomes the equilibrium phase beyond a "terminal" value of the polydispersity. A crystal-to-glass transition is also observed as the density is increased at high polydispersity. The phase diagram obtained in our study is qualitatively similar to that of hard spheres in a quenched random potential.
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Affiliation(s)
- Pinaki Chaudhuri
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India
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