51
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Zhang H, Qiao K, Han Y. Power laws in pressure-induced structural change of glasses. Nat Commun 2020; 11:2005. [PMID: 32332710 PMCID: PMC7181815 DOI: 10.1038/s41467-020-15583-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 03/08/2020] [Indexed: 11/27/2022] Open
Abstract
Many glasses exhibit fractional power law (FPL) between the mean atomic volume va and the first diffraction peak position q1, i.e. \documentclass[12pt]{minimal}
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\begin{document}$$v_{\mathrm{a}} \propto q_1^{ - d}$$\end{document}va∝q1−d with d ≃ 2.5 deviating from the space dimension D = 3, under compression or composition change. What structural change causes such FPL and whether the FPL and d are universal remain controversial. Here our simulations show that the FPL holds in both two- and three-dimensional glasses under compression when the particle interaction has two length scales which can induce nonuniform local deformations. The exponent d is not universal, but varies linearly with the deformable part of soft particles. In particular, we reveal an unexpected crossover regime with d > D from crystal behavior (d = D) to glass behavior (d < D). The results are explained by two types of bond deformation. We further discover FPLs in real space from the radial distribution functions, which correspond to the FPLs in reciprocal space. A puzzle in metallic glass research is the existence of the fractional power law in reciprocal space, whilst its origin remains controversial. Zhang et al. show that nonuniform local deformations under compression induce this phenomenon and quantify the power law exponent at both two and three dimensions.
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Affiliation(s)
- Huijun Zhang
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Kaiyao Qiao
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Yilong Han
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
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52
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Paret J, Jack RL, Coslovich D. Assessing the structural heterogeneity of supercooled liquids through community inference. J Chem Phys 2020; 152:144502. [DOI: 10.1063/5.0004732] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Joris Paret
- Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, Montpellier, France
| | - Robert L. Jack
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom
| | - Daniele Coslovich
- Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, Montpellier, France
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53
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Drewitt JWE, Turci F, Heinen BJ, Macleod SG, Qin F, Kleppe AK, Lord OT. Structural Ordering in Liquid Gallium under Extreme Conditions. PHYSICAL REVIEW LETTERS 2020; 124:145501. [PMID: 32338984 DOI: 10.1103/physrevlett.124.145501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/20/2020] [Indexed: 06/11/2023]
Abstract
The atomic-scale structure, melting curve, and equation of state of liquid gallium has been measured to high pressure (p) and high temperature (T) up to 26 GPa and 900 K by in situ synchrotron x-ray diffraction. Ab initio molecular dynamics simulations up to 33.4 GPa and 1000 K are in excellent agreement with the experimental measurements, providing detailed insight at the level of pair distribution functions. The results reveal an absence of dimeric bonding in the liquid state and a continuous increase in average coordination number n[over ¯]_{Ga}^{Ga} from 10.4(2) at 0.1 GPa approaching ∼12 by 25 GPa. Topological cluster analysis of the simulation trajectories finds increasing fractions of fivefold symmetric and crystalline motifs at high p-T. Although the liquid progressively resembles a hard-sphere structure towards the melting curve, the deviation from this simple description remains large (≥40%) across all p-T space, with specific motifs of different geometries strongly correlating with low local two-body excess entropy at high p-T.
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Affiliation(s)
- James W E Drewitt
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom
| | - Francesco Turci
- H H Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - Benedict J Heinen
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom
| | - Simon G Macleod
- Atomic Weapons Establishment, Aldermaston, Reading RG7 4PR, United Kingdom
- SUPA, School of Physics and Astronomy, and Centre for Science at Extreme Conditions, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - Fei Qin
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom
| | - Annette K Kleppe
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Chilton OX11 0DE, United Kingdom
| | - Oliver T Lord
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom
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54
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Roberts RC, Marioni N, Palmer JC, Conrad JC. Dynamics of polydisperse hard-spheres under strong confinement. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1728407] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Ryan C. Roberts
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, USA
| | - Nico Marioni
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, USA
| | - Jeremy C. Palmer
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, USA
| | - Jacinta C. Conrad
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, USA
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55
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Fiorucci G, Coli GM, Padding JT, Dijkstra M. The effect of hydrodynamics on the crystal nucleation of nearly hard spheres. J Chem Phys 2020; 152:064903. [DOI: 10.1063/1.5137815] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Giulia Fiorucci
- Soft Condensed Matter, Debye Institute for Nanomaterials Science, Department of Physics, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Gabriele M. Coli
- Soft Condensed Matter, Debye Institute for Nanomaterials Science, Department of Physics, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Johan T. Padding
- Process and Energy Department, TU Delft, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
| | - Marjolein Dijkstra
- Soft Condensed Matter, Debye Institute for Nanomaterials Science, Department of Physics, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
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56
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Balbuena C, Soulé ER. An alternative approach to evidence the structural conditioning in the dynamic slowdown in a polymer glass-former. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:045401. [PMID: 31577994 DOI: 10.1088/1361-648x/ab4a67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Dynamic slowdown of liquids, leading to a breakdown of Arrhenius behavior of relaxation and Stokes-Einstein relationship (SER), as the glass transition is approached, is still not fully understood despite decades of study. They are usually associated to the emergence of dynamic heterogeneity, that is, regions or clusters of particles that have high or low mobilities. But the physical origin of these dynamic heterogeneity, and in particular, the question whether they have a structural origin or they are a purely dynamical phenomenon, is still under debate. In this work we study through molecular dynamics simulations in a polymer model the dynamic slowdown and the breakdown of SER, in connection with dynamic susceptibility calculated for an isoconfigurational ensemble, such that the effects of structure on dynamics can be discriminated. The onset of structure effects on dynamical behavior is found to be coincident with the onset of slow dynamics and SER breakdown.
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Affiliation(s)
- Cristian Balbuena
- Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), J. B. Justo 4302, 7600 Mar del Plata, Argentina
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57
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Ryu CW, Dmowski W, Kelton KF, Lee GW, Park ES, Morris JR, Egami T. Curie-Weiss behavior of liquid structure and ideal glass state. Sci Rep 2019; 9:18579. [PMID: 31819088 PMCID: PMC6901545 DOI: 10.1038/s41598-019-54758-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 11/12/2019] [Indexed: 12/02/2022] Open
Abstract
We present the results of a structural study of metallic alloy liquids from high temperature through the glass transition. We use high energy X-ray scattering and electro-static levitation in combination with molecular dynamics simulation and show that the height of the first peak of the structure function, S(Q) - 1, follows the Curie-Weiss law. The structural coherence length is proportional to the height of the first peak, and we suggest that its increase with cooling may be related to the rapid increase in viscosity. The Curie temperature is negative, implying an analogy with spin-glass. The Curie-Weiss behavior provides a pathway to an ideal glass state, a state with long-range correlation without lattice periodicity, which is characterized by highly diverse local structures, reminiscent of spin-glass.
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Affiliation(s)
- C W Ryu
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996, USA
- Research Institute of Advanced Materials, Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - W Dmowski
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996, USA
| | - K F Kelton
- Department of Physics and Institute of Materials Science and Engineering, Washington University, St. Louis, MO, 63130, USA
| | - G W Lee
- Korea Research Institute of Standards and Science, Daejon, 34113, Republic of Korea
- Department of Nano Science, University of Science and Technology, Daejon, 34113, Republic of Korea
| | - E S Park
- Research Institute of Advanced Materials, Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - J R Morris
- Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Ames Laboratory, Ames, IA, 50011, USA
| | - T Egami
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996, USA.
- Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA.
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58
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Tong H, Tanaka H. Structural order as a genuine control parameter of dynamics in simple glass formers. Nat Commun 2019; 10:5596. [PMID: 31811143 PMCID: PMC6898187 DOI: 10.1038/s41467-019-13606-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/13/2019] [Indexed: 11/13/2022] Open
Abstract
Glass transition is characterised by drastic dynamical slowing down upon cooling, accompanied by growing spatial heterogeneity. Its rationalisation by subtle changes in the liquid structure has been long debated but remains elusive, due to intrinsic difficulty in detecting the underlying complex structural ordering. Here we report that structural order parameter characterising local packing capability can well describe the glassy dynamics not only macroscopically but also microscopically, no matter whether it is driven by temperature or density. A Vogel-Fulcher-Tammann (VFT)-like relation is universally identified between the structural relaxation time and the order parameter for supercooled liquids with isotropic interactions. More importantly, we find such an intriguing VFT-like relation to be statistically valid even at a particle level, between spatially coarse-grained structural order and microscopic particle-level dynamics. Such a unified description of glassy dynamics based solely on structural order is expected to contribute to the ultimate understanding of the long-standing glass-transition problem. The glass-forming materials exhibit dynamical slowing down together with spatial heterogeneity at microscales, but their origin remains debated. Tong and Tanaka show that this phenomenon can be unified based on a structural order parameter capable of detecting subtle ordering in instantaneous liquid states.
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Affiliation(s)
- Hua Tong
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan
| | - Hajime Tanaka
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.
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59
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Klongvessa N, Ginot F, Ybert C, Cottin-Bizonne C, Leocmach M. Nonmonotonic behavior in dense assemblies of active colloids. Phys Rev E 2019; 100:062603. [PMID: 31962398 DOI: 10.1103/physreve.100.062603] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Indexed: 06/10/2023]
Abstract
We study experimentally a sediment of self-propelled Brownian particles with densities ranging from dilute to ergodic supercooled to nonergodic glass to nonergodic polycrystal. In a companion paper, we observe a nonmonotonic response to activity of relaxation of the nonergodic glass state: a dramatic slowdown when particles become weakly self-propelled, followed by a speedup at higher activities. Here we map ergodic supercooled states to standard passive glassy physics, provided a monotonic shift of the glass packing fraction and the replacement of the ambient temperature by the effective temperature. However, we show that this mapping fails beyond glass transition. This failure is responsible for the nonmonotonic response. Furthermore, we generalize our finding by examining the dynamical response of another class of nonergodic systems: polycrystals. We observe the same nonmonotonic response to activity. To explain this phenomenon, we measure the size of domains where particles move in the same direction. This size also shows a nonmonotonic response, with small lengths corresponding to slow relaxation. This suggests that the failure of the mapping of nonergodic active states to a passive situation is general and is linked to anisotropic relaxation mechanisms specific to active matter.
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Affiliation(s)
- Natsuda Klongvessa
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, VILLEURBANNE, France
| | - Félix Ginot
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, VILLEURBANNE, France
| | - Christophe Ybert
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, VILLEURBANNE, France
| | - Cécile Cottin-Bizonne
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, VILLEURBANNE, France
| | - Mathieu Leocmach
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, VILLEURBANNE, France
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60
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Zhang W, Douglas JF, Starr FW. What does the instantaneous normal mode spectrum tell us about dynamical heterogeneity in glass-forming fluids? J Chem Phys 2019; 151:184904. [PMID: 31731864 DOI: 10.1063/1.5127821] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We examine the instantaneous normal mode spectrum of model metallic and polymeric glass-forming liquids. We focus on the localized modes in the unstable part of the spectrum [unstable localized (UL) modes] and find that the particles making the dominant contribution to the participation ratio form clusters that grow upon cooling in a fashion similar to the dynamical heterogeneity in glass-forming fluids, i.e., highly mobile (or immobile) particles form clusters that grow upon cooling; however, a comparison of the UL mode clusters to the mobile and immobile particle clusters indicates that they are distinct entities. We also show that the cluster size provides an alternate method to distinguish localized and delocalized modes, offering a significant practical advantage over the finite-size scaling approach. We examine the trajectories of particles contributing most to the UL modes and find that they have a slightly enhanced mobility compared to the average, and we determine a characteristic time quantifying the persistence time of this excess mobility. This time scale is proportional to the structural relaxation time τα of the fluid, consistent with a prediction by Zwanzig [Phys. Rev. 156, 190 (1967)] for the lifetime of collective excitations in cooled liquids. Evidently, these collective excitations serve to facilitate relaxation but do not actually participate in the motion associated with barrier crossing events governing activated transport. They also serve as a possible concrete realization of the "facilitation" clusters postulated in previous modeling of glass-forming liquids.
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Affiliation(s)
- Wengang Zhang
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Francis W Starr
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
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61
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Ravinder R, Garg P, Krishnan NMA. Glass Transition and Crystallization in Hexagonal Boron Nitride: Crucial Role of Orientational Order. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- R. Ravinder
- Department of Civil EngineeringIndian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
| | - Prateet Garg
- Department of Civil EngineeringIndian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
| | - N. M. Anoop Krishnan
- Department of Civil EngineeringIndian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
- Department of Materials Science and EngineeringIndian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
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62
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Shankaraiah N, Sengupta S, Menon GI. Orientational correlations in fluids with quenched disorder. J Chem Phys 2019; 151:124501. [PMID: 31575199 DOI: 10.1063/1.5116734] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Snapshots of colloidal particles moving on disordered two-dimensional substrates can be used to extract equal-time many-body correlations in their positions. To understand the systematics of these correlations, we perform Monte Carlo simulations of a two-dimensional model fluid placed in a quenched disordered background. We use configurations generated from these simulations to compute translational and orientational two-point correlations at equal time, concentrating on correlations in local orientational order as a function of density and disorder strength. We calculate both the disorder averaged version of conventional two-point correlation functions for orientational order, as well as the disorder averaged version of a novel correlation function of time-averaged disorder-induced inhomogeneities in local orientation analogous to the Edwards-Anderson correlation function in spin systems. We demonstrate that these correlations can exhibit interesting nonmonotonic behavior in proximity to the underlying fluid-solid transition and suggest that this prediction should be experimentally accessible.
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Affiliation(s)
- N Shankaraiah
- TIFR Centre for Interdisciplinary Sciences, 36/p Gopanpally, Hyderabad 500107, India
| | - Surajit Sengupta
- TIFR Centre for Interdisciplinary Sciences, 36/p Gopanpally, Hyderabad 500107, India
| | - Gautam I Menon
- The Institute of Mathematical Sciences, C.I.T Campus, Taramani, Chennai 600113, India
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63
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Chandran S, Baschnagel J, Cangialosi D, Fukao K, Glynos E, Janssen LMC, Müller M, Muthukumar M, Steiner U, Xu J, Napolitano S, Reiter G. Processing Pathways Decide Polymer Properties at the Molecular Level. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01195] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
| | - Jörg Baschnagel
- Institut Charles Sadron, Université de Strasbourg & CNRS, 23 rue du Loess, 67034 Cedex, Strasbourg, France
| | - Daniele Cangialosi
- Centro de Física de Materiales CFM (CSIC-UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 San Sebastin, Spain
| | - Koji Fukao
- Department of Physics, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Emmanouil Glynos
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, P.O.
Box 1385, 711 10 Heraklion, Crete, Greece
| | - Liesbeth M. C. Janssen
- Theory of Polymers and Soft Matter, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, The Netherlands
| | - Marcus Müller
- Institute for Theoretical Physics, Georg-August-Universität, Göttingen, Germany
| | - Murugappan Muthukumar
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Ullrich Steiner
- Adolphe Merkle Institute, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Jun Xu
- Advanced Materials Laboratory of Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Simone Napolitano
- Laboratory of Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics, Faculté des Sciences, Université libre de Bruxelles (ULB), CP223, Boulevard du Triomphe, Bruxelles 1050, Belgium
| | - Günter Reiter
- Institute of Physics, University of Freiburg, Freiburg 79104, Germany
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64
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Balbuena C, Gianetti MM, Soulé ER. Static and dynamic correlation lengths in supercooled polymers. J Chem Phys 2019; 150:234508. [PMID: 31228894 DOI: 10.1063/1.5091682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A key point to understand the glass transition is the relationship between structural and dynamic behavior experienced by a glass former when it approaches Tg. In this work, the relaxation in a simple bead-spring polymer system in the supercooled regime near its glass transition temperature was investigated with molecular dynamic simulations. We develop a new manner to look at the dynamic length scales in a supercooled polymeric system, focusing on correlated motion of particles in an isoconfigurational ensemble (that is, associated with the structure), as measured by Pearson's correlation coefficient. We found that while the usual dynamic four-point correlation length deviates from the structural (mosaic or point-to-set) length scale at low temperatures, Pearson's length behaves similarly to the static length in the whole temperature range. The results lead to a consensus of similar scaling of structural and dynamical length scales, reinforcing the idea of the theories of Adam-Gibbs and random first order transition.
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Affiliation(s)
- Cristian Balbuena
- Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), J. B. Justo 4302, 7600 Mar del Plata, Argentina
| | - Melisa M Gianetti
- Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), J. B. Justo 4302, 7600 Mar del Plata, Argentina
| | - Ezequiel R Soulé
- Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), J. B. Justo 4302, 7600 Mar del Plata, Argentina
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65
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Yang X, Tong H, Wang WH, Chen K. Emergence and percolation of rigid domains during the colloidal glass transition. Phys Rev E 2019; 99:062610. [PMID: 31330594 DOI: 10.1103/physreve.99.062610] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Indexed: 06/10/2023]
Abstract
Using video microscopy, we measure local spatial constraints in disordered binary colloidal samples, ranging from dilute fluids to jammed glasses, and probe their spatial and temporal correlations to local dynamics during the glass transition. We observe the emergence of significant correlations between constraints and local dynamics within the Lindemann criterion, which coincides with the onset of glassy dynamics in supercooled liquids. Rigid domains in fluids are identified based on local constraints and demonstrate a percolation transition near the glass transition, accompanied by the emergence of dynamical heterogeneities. Our results show that spatial constraint instead of the geometry of amorphous structures is the key that connects the complex spatial-temporal correlations in disordered materials.
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Affiliation(s)
- Xiunan Yang
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Hua Tong
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Wei-Hua Wang
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Ke Chen
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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66
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Tang X, Chen W, Li L. The Tough Journey of Polymer Crystallization: Battling with Chain Flexibility and Connectivity. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02725] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Xiaoliang Tang
- National Synchrotron Radiation Lab, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Wei Chen
- National Synchrotron Radiation Lab, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Liangbin Li
- National Synchrotron Radiation Lab, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China
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67
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A universal state and its relaxation mechanisms of long-range interacting polygons. Nat Commun 2019; 10:1737. [PMID: 30988297 PMCID: PMC6465257 DOI: 10.1038/s41467-019-09795-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 03/31/2019] [Indexed: 11/08/2022] Open
Abstract
Using polygonal magnetic particles, we conduct experiments to explore the space-filling properties of anisotropic blocks with long-range interactions. In contrast to previous studies, we obtain the surprising finding that our systems' structures do not depend on the shape of building blocks: a single state, the hexagonal plastic crystal, appears as a universal attractor for a wide range of different polygons. This robust particle-shape independency appears as the interactions go beyond nearest neighbors. Particle shape plays an essential role in system relaxation, and determines the basic relaxation dynamics through a microscopic control parameter, internal roughness, produced by particle vertices. Thus our study reveals a new pattern-forming paradigm, in which particle shape plays little role in the static structure but determines the essential relaxation dynamics. Due to the ubiquity of long-range interactions and anisotropic building blocks, our discovery may shed new light on diverse problems involving structure formation, self-assembly, and packing.
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68
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Azizi I, Rabin Y. Identity ordering and metastable clusters in fluids with random interactions. J Chem Phys 2019; 150:134502. [PMID: 30954053 DOI: 10.1063/1.5083218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We use Langevin dynamics simulations to study dense two-dimensional systems of particles where all binary interactions are different in the sense that each interaction parameter is characterized by a randomly chosen number. We compare two systems that differ by the probability distributions from which the interaction parameters are drawn: uniform (U) and exponential (E). Both systems undergo neighborhood identity ordering and form metastable clusters in the fluid phase near the liquid-solid transition, but the effects are much stronger in E than in U systems. Possible implications of our results for the control of the structure of multicomponent alloys are discussed.
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Affiliation(s)
- Itay Azizi
- Department of Physics, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Yitzhak Rabin
- Department of Physics, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
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69
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Qing L, Li Y, Tang W, Zhang D, Han Y, Zhao S. Dynamic Adsorption of Ions into Like-Charged Nanospace: A Dynamic Density Functional Theory Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:4254-4262. [PMID: 30839219 DOI: 10.1021/acs.langmuir.9b00088] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The adsorption processes of ions into charged nanospace are associated with many practical applications. Whereas a large number of microporous materials have been prepared toward efficient adsorption of ions from solutions, theoretical models that allow for capturing the characteristics of ion dynamic adsorption into like-charged nanopores are still few. The difficulty originates from the overlapping of electric potentials inside the pores. Herein, a theoretical model is proposed by incorporating dynamic density functional theory with modified Poisson equation for investigating the dynamic adsorption of ions into like-charged nanoslits. This model is rationalized by comparing the theoretical predictions with corresponding simulation results. Afterward, by analyzing the adsorption dynamics, we show that the overlapping effect is associated with the pore size, ion bulk concentration, and surface charge density, and it plays a dominant role in the coupling between the total adsorption amount of ions and total adsorption time. Specifically, with weak overlapping effect, the total adsorption amount is intuitively proportional to the total adsorption time; however, when the overlapping effect is strong, the total adsorption amount may be inversely proportional to the total adsorption time, indicating that both high adsorption amount and short adsorption time can be achieved simultaneously. This work provides a meaningful insight toward the rational design and optimization of microporous materials for efficient ion adsorption.
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Affiliation(s)
- Leying Qing
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
| | - Yu Li
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
| | - Weiqiang Tang
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
| | - Duo Zhang
- Ecole Nationale Supérieure des Ingénieurs en Arts Chimiques et Technologiques de Toulouse , Toulouse 31030 , France
| | - Yongsheng Han
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering , Chinese Academy of Sciences , 100190 Beijing , China
- School of Chemical Engineering , University of Chinese Academy of Sciences , 100049 Beijing , China
| | - Shuangliang Zhao
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
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70
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Evidence of a two-dimensional glass transition in graphene: Insights from molecular simulations. Sci Rep 2019; 9:4517. [PMID: 30872750 PMCID: PMC6418284 DOI: 10.1038/s41598-019-41231-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 03/05/2019] [Indexed: 11/23/2022] Open
Abstract
Liquids exhibit a sudden increase in viscosity when cooled fast enough, avoiding thermodynamically predicted route of crystallization. This phenomenon, known as glass transition, leads to the formation of non-periodic structures known as glasses. Extensive studies have been conducted on model materials to understand glass transition in two dimensions. However, despite the synthesis of disordered/amorphous single-atom thick structures of carbon, little attention has been given to glass transition in realistic two-dimensional materials such as graphene. Herein, using molecular dynamics simulation, we demonstrate the existence of glass transition in graphene leading to a realistic two-dimensional glassy structure, namely glassy graphene. We show that the resulting glassy structure exhibits excellent agreement with experimentally realized disordered graphene. Interestingly, this glassy graphene exhibits a wrinkled but stable structure, with reduced thermal vibration in comparison to its crystalline counterpart. We suggest that the topological disorder induced by glass transition governs the unique properties of this structure.
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71
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Debot A, White RP, Lipson JEG, Napolitano S. Experimental Test of the Cooperative Free Volume Rate Model under 1D Confinement: The Interplay of Free Volume, Temperature, and Polymer Film Thickness in Driving Segmental Mobility. ACS Macro Lett 2019; 8:41-45. [PMID: 35619409 DOI: 10.1021/acsmacrolett.8b00844] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We show that the Cooperative Free Volume (CFV) rate model, successful at modeling pressure-dependent dynamics, can be employed to describe the temperature and thickness dependence of the segmental time of polymers confined in thin films (1D confinement). The CFV model is based on an activation free energy that increases with the number of cooperating segments, which is determined by the system's free volume. Here, we apply the CFV model to new experimental results on the segmental relaxation of 1D confined poly(4-chlorostyrene), P4ClS, and find remarkable agreement over the whole temperature and thickness ranges investigated. This work further validates the robustness of the CFV model, which relates the effects of confinement on dynamics to pressure changes in the bulk, and supports the idea that confinement effects originate from local perturbations in density.
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Affiliation(s)
- Alice Debot
- Polymer and Soft Matter Dynamics, Faculté des Sciences, Université libre de Bruxelles (ULB), Brussels, Belgium
| | - Ronald P. White
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Jane E. G. Lipson
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Simone Napolitano
- Polymer and Soft Matter Dynamics, Faculté des Sciences, Université libre de Bruxelles (ULB), Brussels, Belgium
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72
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Wojnarowska Z, Tajber L, Paluch M. Density Scaling in Ionic Glass Formers Controlled by Grotthuss Conduction. J Phys Chem B 2019; 123:1156-1160. [DOI: 10.1021/acs.jpcb.8b09396] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Z. Wojnarowska
- Institute of Physics, University of Silesia, SMCEBI, 75 Pulku Piechoty 1A, Chorzow 41-500, Poland
- School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, College Green, Dublin 2, Ireland
| | - L. Tajber
- School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, College Green, Dublin 2, Ireland
| | - M. Paluch
- Institute of Physics, University of Silesia, SMCEBI, 75 Pulku Piechoty 1A, Chorzow 41-500, Poland
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73
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Zhang W, Yan Q, Ye K, Zhang Q, Chen W, Meng L, Chen X, Wang D, Li L. The effect of water absorption on stretch-induced crystallization of poly(ethylene terephthalate): An in-situ synchrotron radiation wide angle X-ray scattering study. POLYMER 2019. [DOI: 10.1016/j.polymer.2018.12.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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74
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Zong Y, Chen K, Mason TG, Zhao K. Vibrational Modes and Dynamic Heterogeneity in a Near-Equilibrium 2D Glass of Colloidal Kites. PHYSICAL REVIEW LETTERS 2018; 121:228003. [PMID: 30547612 DOI: 10.1103/physrevlett.121.228003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 09/04/2018] [Indexed: 06/09/2023]
Abstract
Using video microscopy and particle-tracking techniques developed for dense Brownian systems of polygons, we study the structure-dynamics relationship in a near-equilibrium 2D glass consisting of anisotropic Penrose kite-shaped colloids. Detailed vibrational properties of kite glasses, both translational and rotational, are obtained using covariance matrix techniques. Different from other colloidal glasses of spheres and ellipsoids, the vibrational modes of kite glasses at low frequencies show a strong translational character with spatially localized rotational modes and extended translational modes. Low-frequency quasilocalized soft modes commonly found in sphere glasses are absent in the translational phonon modes of kite glasses. Soft modes are observed predominantly in the rotational vibrations and correlate well with the spatial distribution of Debye-Waller factors. The local structural entropy field shows a strong correlation with the observed dynamic heterogeneity.
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Affiliation(s)
- Yiwu Zong
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
| | - Ke Chen
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Thomas G Mason
- Department of Physics and Astronomy, University of California-Los Angeles, Los Angeles, California 90095, USA
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, USA
| | - Kun Zhao
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
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75
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Godfrin PD, Falus P, Porcar L, Hong K, Hudson SD, Wagner NJ, Liu Y. Dynamic properties of different liquid states in systems with competing interactions studied with lysozyme solutions. SOFT MATTER 2018; 14:8570-8579. [PMID: 30320333 DOI: 10.1039/c8sm01678j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Recent studies of colloidal systems with a short-range attraction and long-range repulsion (SALR) have been demonstrated to have a generalized phase diagram with multiple liquid states defined by their structures. In this paper, we identify the different liquid states of previous experimentally studied lysozyme samples within this proposed generalized state diagram and explore the dynamic properties of each liquid state. We show that most lysozyme samples studied here and previously at low and intermediate concentrations are dispersed fluids while a few high concentration samples are randomly percolated liquids. In the dispersed fluid region, the short-time diffusion coefficient measured by neutron spin echo agrees well with the long time diffusion coefficient estimated with the solution viscosity. This dynamic feature is maintained even for some samples in the random percolated region. However, the short-time and long-time diffusion coefficients of random percolated fluids deviate at larger concentration and attraction strength. At high enough concentrations, the mean square displacement can be as slow as those of many glassy colloidal systems at time scales near the characteristic diffusion time even though these lysozyme samples remain in liquid states at the long-time limit. We thus identify the region in the generalized phase diagram where these equilibrium states with extremely slow local dynamics exist relative to bulk percolation and kinetic arrest (gel and glassy) transitions.
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Affiliation(s)
- P D Godfrin
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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76
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Das T, Douglas JF. Quantifying structural dynamic heterogeneity in a dense two-dimensional equilibrium liquid. J Chem Phys 2018; 149:144504. [DOI: 10.1063/1.5037282] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Tamoghna Das
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA and Maryland Nanocenter, University of Maryland, College Park, Maryland 20742, USA
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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77
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Liu L, Yu Z, Jin W, Yuan Y, Li S. Uniform and decoupled shape effects on the maximally dense random packings of hard superellipsoids. POWDER TECHNOL 2018. [DOI: 10.1016/j.powtec.2018.06.033] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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78
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Asai M, Cacciuto A, Kumar SK. Surface Fluctuations Dominate the Slow Glassy Dynamics of Polymer-Grafted Colloid Assemblies. ACS CENTRAL SCIENCE 2018; 4:1179-1184. [PMID: 30276251 PMCID: PMC6161052 DOI: 10.1021/acscentsci.8b00352] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Indexed: 05/16/2023]
Abstract
Colloids grafted with a corona layer of polymers show glassy behavior that covers a wide range of fragilities, with this behavior being tunable through variations in grafting density and grafting chain length. We find that the corona roughness, which is maximized for long chain lengths and sparse grafting, is directly correlated to the concentration-dependence of the system relaxation time (fragility). Relatively rougher colloids result in stronger liquids because their rotational motions become orientationally correlated across the whole system even at low particle loadings leading to an essentially Arrhenius-like concentration-dependence of the relaxation times near the glass transition. The smoother colloids do not show as much orientational correlation except at higher densities leading to fragile behavior. We therefore propose that these materials are an ideal model to study the physical properties of the glass transition.
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Affiliation(s)
- Makoto Asai
- Department
of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Angelo Cacciuto
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Sanat K. Kumar
- Department
of Chemical Engineering, Columbia University, New York, New York 10027, United States
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79
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Direct determination of structural heterogeneity in metallic glasses using four-dimensional scanning transmission electron microscopy. Ultramicroscopy 2018; 195:189-193. [PMID: 30384139 DOI: 10.1016/j.ultramic.2018.09.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 09/04/2018] [Accepted: 09/12/2018] [Indexed: 11/22/2022]
Abstract
We report the first direct quantification of the structural heterogeneity in metallic glasses using intensity variance and angular correlation analyses of the 4-dimensional (4-D) scanning transmission electron microscopy (STEM) data. We demonstrate that the real-space reconstruction and analyses of the 4-D nanodiffraction data acquired using a pixelated fast STEM detector enables quantitative determination of the details of local structural heterogeneity, including the type, size, volume fraction and spatial distribution of local ordering at the nano- to meso-scale, beyond the limits of the previous measurements using conventional detectors. We show that different types of local ordering are present in Zr55Co25Al20 glass, leading to a high degree of structural heterogeneity, with the total volume of locally ordered regions making up to ∼14% of the entire volume. These findings are significant, as the structure-property relationship in metallic glasses and other amorphous materials has been difficult to establish because of the lack of detailed structural information from experiments.
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80
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Royall CP, Turci F, Tatsumi S, Russo J, Robinson J. The race to the bottom: approaching the ideal glass? JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:363001. [PMID: 29972145 DOI: 10.1088/1361-648x/aad10a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Key to resolving the scientific challenge of the glass transition is to understand the origin of the massive increase in viscosity of liquids cooled below their melting temperature (avoiding crystallisation). A number of competing and often mutually exclusive theoretical approaches have been advanced to describe this phenomenon. Some posit a bona fide thermodynamic phase to an 'ideal glass', an amorphous state with exceptionally low entropy. Other approaches are built around the concept of the glass transition as a primarily dynamic phenomenon. These fundamentally different interpretations give equally good descriptions of the data available, so it is hard to determine which-if any-is correct. Recently however this situation has begun to change. A consensus has emerged that one powerful means to resolve this longstanding question is to approach the putative thermodynamic transition sufficiently closely, and a number of techniques have emerged to meet this challenge. Here we review the results of some of these new techniques and discuss the implications for the existence-or otherwise-of the thermodynamic transition to an ideal glass.
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Affiliation(s)
- C Patrick Royall
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom. School of Chemistry, University of Bristol, Cantock Close, Bristol, BS8 1TS, United Kingdom. Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol, BS8 1FD, United Kingdom
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81
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Balbuena C, Gianetti MM, Soulé ER. Looking at the dynamical heterogeneity in a supercooled polymer system through isoconfigurational ensemble. J Chem Phys 2018; 149:094506. [DOI: 10.1063/1.5039644] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Cristian Balbuena
- Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), J. B. Justo 4302, 7600 Mar del Plata, Argentina
| | - Melisa M. Gianetti
- Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), J. B. Justo 4302, 7600 Mar del Plata, Argentina
| | - Ezequiel R. Soulé
- Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), J. B. Justo 4302, 7600 Mar del Plata, Argentina
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82
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Chen Z, Qi W, Bowles RK. Glass forming phase diagram and local structure of Kob-Andersen binary Lennard-Jones nanoparticles. J Chem Phys 2018; 149:094502. [PMID: 30195318 DOI: 10.1063/1.5047465] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Molecular dynamics simulation is used to study glass formation in Kob-Andersen binary Lennard-Jones nanoparticles and determine the glass forming phase diagram for the system as a function of composition. The radial distribution function, a Steinhardt bond-orientational order parameter, and favored local structure analysis are used to distinguish between glassy and ordered systems. We find that surface enrichment of the large atoms alters the nanoparticle core composition, leading to an overall shift of the glass forming region to lower small atom mole fractions, relative to the bulk system. At small atom mole fraction, xB = 0.1, the nanoparticles form a solid with an amorphous core, enriched with the small atoms, surrounded by a partially ordered surface region, enriched with the large atom component. The most disordered glass nanoparticles occur at xB ≈ 0.3, but the surface-core enrichment leads to the crystallization of the nanoparticle to the CsCl crystal above xB ≈ 0.35, which is lower than observed in the bulk. The glass transition temperatures of the nanoparticles are also significantly reduced. This allows the liquid to remain dynamic to low temperatures and sample the low energy inherent structure minima on the potential energy surface containing a high abundance of favoured local structures.
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Affiliation(s)
- Zhongquan Chen
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Weikai Qi
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Richard K Bowles
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
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83
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Klochko L, Baschnagel J, Wittmer JP, Semenov AN. Long-range stress correlations in viscoelastic and glass-forming fluids. SOFT MATTER 2018; 14:6835-6848. [PMID: 30091783 DOI: 10.1039/c8sm01055b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A simple and rigorous approach to obtain stress correlations in viscoelastic liquids (including supercooled liquid and equilibrium amorphous systems) is proposed. The long-range dynamical correlations of local shear stress are calculated and analyzed in 2-dimensional space. It is established how the long-range character of the stress correlations gradually emerges as the relevant dynamical correlation length l grows in time. The correlation range l is defined by momentum propagation due to acoustic waves and vorticity diffusion which are the basic mechanisms for transmission of shear stress perturbations. We obtain the general expression defining the time- and distance-dependent stress correlation tensor in terms of material functions (generalized relaxation moduli). The effect of liquid compressibility is quantitatively analyzed; it is shown to be important at large distances and/or short times. The revealed long-range stress correlation effect is shown to be dynamical in nature and unconnected with static structural correlations in liquids (correlation length ξs). Our approach is based on the assumption that ξs is small enough as reflected in weak wave-number dependencies of the generalized relaxation moduli. We provide a simple physical picture connecting the elucidated long-range fluctuation effect with anisotropic correlations of the (transient) inherent stress field, and discuss its implications.
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Affiliation(s)
- L Klochko
- Institut Charles Sadron, CNRS - UPR 22, Université de Strasbourg, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
| | - J Baschnagel
- Institut Charles Sadron, CNRS - UPR 22, Université de Strasbourg, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
| | - J P Wittmer
- Institut Charles Sadron, CNRS - UPR 22, Université de Strasbourg, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
| | - A N Semenov
- Institut Charles Sadron, CNRS - UPR 22, Université de Strasbourg, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
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84
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Tah I, Sengupta S, Sastry S, Dasgupta C, Karmakar S. Glass Transition in Supercooled Liquids with Medium-Range Crystalline Order. PHYSICAL REVIEW LETTERS 2018; 121:085703. [PMID: 30192617 DOI: 10.1103/physrevlett.121.085703] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Indexed: 05/17/2023]
Abstract
The origin of the rapid dynamical slowdown in glass forming liquids in the growth of static length scales, possibly associated with identifiable structural ordering, is a much debated issue. Growth of medium range crystalline order (MRCO) has been observed in various model systems to be associated with glassy behavior. Such observations raise the question of whether molecular mechanisms for the glass transition in liquids with and without MRCO are the same. In this study we perform extensive molecular dynamics simulations of a number of glass forming liquids and show that the static and dynamic properties of glasses with MRCO are different from those of other glass forming liquids with no predominant local order. We also resolve an important issue regarding the so-called point-to-set method for determining static length scales, and demonstrate it to be a robust method for determining static correlation lengths in glass formers.
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Affiliation(s)
- Indrajit Tah
- Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500107, India
| | - Shiladitya Sengupta
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, Japan
| | - Srikanth Sastry
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Chandan Dasgupta
- Department of Physics, Indian Institute of Science, Bangalore, 560012, India
- International Centre for Theoretical Sciences, Bangalore 560089, India
| | - Smarajit Karmakar
- Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500107, India
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85
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Hallett JE, Turci F, Royall CP. Local structure in deeply supercooled liquids exhibits growing lengthscales and dynamical correlations. Nat Commun 2018; 9:3272. [PMID: 30115905 PMCID: PMC6095888 DOI: 10.1038/s41467-018-05371-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 07/02/2018] [Indexed: 11/17/2022] Open
Abstract
Glasses are among the most widely used of everyday materials, yet the process by which a liquid's viscosity increases by 14 decades to become a glass remains unclear, as often contradictory theories provide equally good descriptions of the available data. Knowledge of emergent lengthscales and higher-order structure could help resolve this, but this requires time-resolved measurements of dense particle coordinates-previously only obtained over a limited time interval. Here we present an experimental study of a model colloidal system over a dynamic window significantly larger than previous measurements, revealing structural ordering more strongly linked to dynamics than previously found. Furthermore we find that immobile regions and domains of local structure grow concurrently with density, and that these regions have low configurational entropy. We thus show that local structure plays an important role at deep supercooling, consistent with a thermodynamic interpretation of the glass transition rather than a principally dynamic description.
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Affiliation(s)
- James E Hallett
- H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol, BS8 1TL, UK
- Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol, BS8 1FD, UK
| | - Francesco Turci
- H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol, BS8 1TL, UK
- Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol, BS8 1FD, UK
| | - C Patrick Royall
- H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol, BS8 1TL, UK.
- Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol, BS8 1FD, UK.
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
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86
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Abstract
The assembly of materials from building blocks has been in the core of a wide range of applications from catalysis to photonics and electronics. External electric fields enable the interactions between building blocks to be controlled via induced dipoles. Dipolar interactions were used so far to obtain one-dimensional chains or three-dimensional non-close-packed lattices. However, complex colloidal assemblies and clusters of simple spherical particles are rare. Here we demonstrate a novel self-assembly approach enabling the formation of regular axially symmetric clusters, an array of colloidal assemblies as per design of posts, and hierarchical complex assemblies by using posts and dipolar interactions or combining them. Regulating the polarization of the particles from positive to negative allows us to control the interparticle interactions from attractive to repulsive at the poles or equator of the particles. Therefore, such particle-particle interactions enable switching between Saturn ring-like and candle-flame-like axially symmetric assemblies, which could potentially be exploited for display applications.
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Affiliation(s)
- Ahmet F Demirörs
- Complex Materials, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
| | - Lauriane Alison
- Complex Materials, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
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87
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Liu WH, Sun BA, Gleiter H, Lan S, Tong Y, Wang XL, Hahn H, Yang Y, Kai JJ, Liu CT. Nanoscale Structural Evolution and Anomalous Mechanical Response of Nanoglasses by Cryogenic Thermal Cycling. NANO LETTERS 2018; 18:4188-4194. [PMID: 29869884 DOI: 10.1021/acs.nanolett.8b01007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
One of the central themes in the amorphous materials research is to understand the nanoscale structural responses to mechanical and thermal agitations, the decoding of which is expected to provide new insights into the complex amorphous structural-property relationship. For common metallic glasses, their inherent atomic structural inhomogeneities can be rejuvenated and amplified by cryogenic thermal cycling, thus can be decoded from their responses to mechanical and thermal agitations. Here, we reported an anomalous mechanical response of a new kind of metallic glass (nanoglass) with nanoscale interface structures to cryogenic thermal cycling. As compared to those metallic glasses by liquid quenching, the Sc75Fe25 (at. %) nanoglass exhibits a decrease in the Young's modulus but a significant increase in the yield strength after cryogenic cycling treatments. The abnormal mechanical property change can be attributed to the complex atomic rearrangements at the short- and medium- range orders due to the intrinsic nonuniformity of the nanoglass architecture. The present work gives a new route for designing high-performance metallic glassy materials by manipulating their atomic structures and helps for understanding the complex atomic structure-property relationship in amorphous materials.
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Affiliation(s)
- Wei-Hong Liu
- Centre for Advanced Structural Materials, Department of Mechanical and Biomechanical Engineering , City University of Hong Kong , Hong Kong , PR China
| | - B A Sun
- Institute of Physics , Chinese Academy of Sciences , 100190 Beijing , PR China
| | - Herbert Gleiter
- Senior member of the Institute for Advanced Study , City University of Hong Kong , Hong Kong , PR China
- Institute of Nanotechnology , Karlsruhe Institute of Technology (KIT) , 76021 Karlsruhe , Germany
| | - Si Lan
- Department of Physics and Material Science , City University of Hong Kong , Hong Kong , PR China
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering , Nanjing University of Science and Technology , 200 Xiaolingwei Avenue , Nanjing , PR China
| | - Yang Tong
- Centre for Advanced Structural Materials, Department of Mechanical and Biomechanical Engineering , City University of Hong Kong , Hong Kong , PR China
- Division of Materials Science and Technology , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , USA
| | - Xun-Li Wang
- Department of Physics and Material Science , City University of Hong Kong , Hong Kong , PR China
| | - Horst Hahn
- Institute of Nanotechnology , Karlsruhe Institute of Technology (KIT) , 76021 Karlsruhe , Germany
| | - Yong Yang
- Centre for Advanced Structural Materials, Department of Mechanical and Biomechanical Engineering , City University of Hong Kong , Hong Kong , PR China
| | - Ji-Jung Kai
- Centre for Advanced Structural Materials, Department of Mechanical and Biomechanical Engineering , City University of Hong Kong , Hong Kong , PR China
| | - C T Liu
- Centre for Advanced Structural Materials, Department of Mechanical and Biomechanical Engineering , City University of Hong Kong , Hong Kong , PR China
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88
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Jenkinson T, Crowther P, Turci F, Royall CP. Weak temperature dependence of ageing of structural properties in atomistic model glassformers. J Chem Phys 2018; 147:054501. [PMID: 28789533 DOI: 10.1063/1.4994836] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ageing phenomena are investigated from a structural perspective in two binary Lennard-Jones glassformers, the Kob-Andersen and Wahnström mixtures. In both, the geometric motif assumed by the glassformer upon supercooling, the locally favoured structure (LFS), has been established. The Kob-Andersen mixture forms bicapped square antiprisms; the Wahnström model forms icosahedra. Upon ageing, we find that the structural relaxation time has a time-dependence consistent with a power law. However, the LFS population and potential energy increase and decrease, respectively, in a logarithmic fashion. Remarkably, over the time scales investigated, which correspond to a factor of 104 change in relaxation times, the rate at which these quantities age appears almost independent of temperature. Only at temperatures far below the Vogel-Fulcher-Tamman temperature do the ageing dynamics slow.
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Affiliation(s)
- Thomas Jenkinson
- H. H. Wills Physics Laboratory, Tyndall Avenue, Bristol, United Kingdom
| | - Peter Crowther
- H. H. Wills Physics Laboratory, Tyndall Avenue, Bristol, United Kingdom
| | - Francesco Turci
- H. H. Wills Physics Laboratory, Tyndall Avenue, Bristol, United Kingdom
| | - C Patrick Royall
- H. H. Wills Physics Laboratory, Tyndall Avenue, Bristol, United Kingdom
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89
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Configuration correlation governs slow dynamics of supercooled metallic liquids. Proc Natl Acad Sci U S A 2018; 115:6375-6380. [PMID: 29866833 DOI: 10.1073/pnas.1802300115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The origin of dramatic slowing down of dynamics in metallic glass-forming liquids toward their glass transition temperatures is a fundamental but unresolved issue. Through extensive molecular dynamics simulations, here we show that, contrary to the previous beliefs, it is not local geometrical orderings extracted from instantaneous configurations but the intrinsic correlation between configurations that captures the structural origin governing slow dynamics. More significantly, it is demonstrated by scaling analyses that it is the correlation length extracted from configuration correlation rather than dynamic correlation lengths that is the key to determine the drastic slowdown of supercooled metallic liquids. The key role of the configuration correlation established here sheds important light on the structural origin of the mysterious glass transition and provides an essential piece of the puzzle for the development of a universal theoretical understanding of glass transition in glasses.
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90
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Pinney R, Liverpool TB, Royall CP. Yielding of a model glass former: An interpretation with an effective system of icosahedra. Phys Rev E 2018; 97:032609. [PMID: 29776085 DOI: 10.1103/physreve.97.032609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Indexed: 11/07/2022]
Abstract
We consider the yielding under simple shear of a binary Lennard-Jones glass former whose super-Arrhenius dynamics are correlated with the formation of icosahedral structures. We recast this glass former as an effective system of icosahedra [Pinney et al., J. Chem. Phys. 143, 244507 (2015)JCPSA60021-960610.1063/1.4938424]. Looking at the small-strain region of sheared simulations, we observe that shear rates affect the shear localization behavior particularly at temperatures below the glass transition as defined with a fit to the Vogel-Fulcher-Tamman equation. At higher temperature, shear localization starts immediately on shearing for all shear rates. At lower temperatures, faster shear rates can result in a delayed start in shear localization, which begins close to the yield stress. Building from a previous work which considered steady-state shear [Pinney et al., J. Chem. Phys. 143, 244507 (2015)JCPSA60021-960610.1063/1.4938424], we interpret the response to shear and the shear localization in terms of a local effective temperature with our system of icosahedra. We find that the effective temperatures of the regions undergoing shear localization increase significantly with increasing strain (before reaching a steady-state plateau).
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Affiliation(s)
- Rhiannon Pinney
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom.,Bristol Centre for Complexity Science, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Tanniemola B Liverpool
- School of Mathematics, University of Bristol, Bristol BS8 1TW, United Kingdom.,BrisSynBio, Tyndall Avenue, Bristol BS8 1TQ, United Kingdom
| | - C Patrick Royall
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom.,School of Chemistry, University of Bristol, Cantock Close, Bristol BS8 1TS, United Kingdom.,Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol BS8 1FD, United Kingdom
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91
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Hung JH, Mangalara JH, Simmons DS. Heterogeneous Rouse Model Predicts Polymer Chain Translational Normal Mode Decoupling. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00135] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Jui-Hsiang Hung
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, United States
| | - Jayachandra Hari Mangalara
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, United States
| | - David S. Simmons
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, United States
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92
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Wang W, Lin JT, Su YS, I L. Micro-structure and motion of two-dimensional dense short spherocylinder liquids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:125102. [PMID: 29437153 DOI: 10.1088/1361-648x/aaaf03] [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
We numerically investigate the micro-structure and motion of 2D liquids composed of dense short spherocylinders, by reducing the shape aspect ratio from 3. It is found that reducing shape aspect ratio from 3 causes a smooth transition from heterogeneous structures composed of crystalline ordered domains with good tetratic alignment order to those with good hexagonal bond-orientational order at an aspect ratio equaling 1.35. In the intermediate regime, both structural orders are strongly deteriorated, and the translational hopping rate reaches a maximum due to the poor particle interlocking of the disordered structure. Shortening rod length allows easier rotation, induces monotonic increase of rotational hopping rates, and resumes the separation of rotational and translational hopping time scales at the small aspect ratio end, after the crossover of their rates in the intermediate regime. At the large shape aspect ratio end, the poor local tetratic order has the same positive effects on facilitating local rotational and translational hopping. In contrast, at the small shape aspect ratio end, the poor local bond orientational order has the opposite effects on facilitating local rotational and translational hopping.
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Affiliation(s)
- Wen Wang
- Department of Physics and Center for Complex Systems, National Central University, Jhongli, Taiwan 32001, Republic of China. Molecular Science and Technology, Taiwan International Graduate Program, Academia Sinica, National Central University, Jhongli, Taiwan 32001, Republic of China
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93
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Wang L, Xu N, Wang WH, Guan P. Revealing the Link between Structural Relaxation and Dynamic Heterogeneity in Glass-Forming Liquids. PHYSICAL REVIEW LETTERS 2018; 120:125502. [PMID: 29694097 DOI: 10.1103/physrevlett.120.125502] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 01/12/2018] [Indexed: 06/08/2023]
Abstract
Despite the use of glasses for thousands of years, the nature of the glass transition is still mysterious. On approaching the glass transition, the growth of dynamic heterogeneity has long been thought to play a key role in explaining the abrupt slowdown of structural relaxation. However, it still remains elusive whether there is an underlying link between structural relaxation and dynamic heterogeneity. Here, we unravel the link by introducing a characteristic time scale hiding behind an identical dynamic heterogeneity for various model glass-forming liquids. We find that the time scale corresponds to the kinetic fragility of liquids. Moreover, it leads to scaling collapse of both the structural relaxation time and dynamic heterogeneity for all liquids studied, together with a characteristic temperature associated with the same dynamic heterogeneity. Our findings imply that studying the glass transition from the viewpoint of dynamic heterogeneity is more informative than expected.
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Affiliation(s)
- Lijin Wang
- Beijing Computational Science Research Center, Beijing 100193, People's Republic of China
| | - Ning Xu
- CAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - W H Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Pengfei Guan
- Beijing Computational Science Research Center, Beijing 100193, People's Republic of China
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94
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Furukawa A. Growing length scale accompanying vitrification: A perspective based on nonsingular density fluctuations. Phys Rev E 2018; 97:022615. [PMID: 29548253 DOI: 10.1103/physreve.97.022615] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Indexed: 11/07/2022]
Abstract
A model for describing growing length scale accompanying the vitrification is introduced, in which we assume that in a subsystem whose density is above a certain threshold value, ρ_{c}, due to steric constraints, particle rearrangements are highly suppressed for a sufficiently long time period (∼structural relaxation time). We regard such a subsystem as a glassy cluster. With this assumption and without introducing any complicated thermodynamic arguments, we predict that with compression (increasing average density ρ) at a fixed temperature T in supercooled states, the characteristic length of the clusters, ξ, diverges as ξ∼(ρ_{c}-ρ)^{-2/d}, where d is the spatial dimensionality. This ξ measures the average persistence length of the steric constraints in blocking the rearrangement motions and is determined by the subsystem density. Additionally, with decreasing T at a fixed ρ, the length scale diverges in the same manner as ξ∼(T-T_{c})^{-2/d}, for which ρ is identical to ρ_{c} at T=T_{c}. The exponent describing the diverging length scale is the same as the one predicted by some theoretical models and indeed has been observed in some simulations and experiments. However, the basic mechanism for this divergence is different; that is, we do not invoke thermodynamic anomalies associated with the thermodynamic phase transition as the origin of the growing length scale. We further present arguements for the cooperative properties of the structural relaxation based on the clusters.
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Affiliation(s)
- Akira Furukawa
- Institute of Industrial Science, University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
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95
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96
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Švajdlenková H, Arrese-Igor S, Nógellová Z, Alegría A, Bartoš J. Molecular dynamic heterogeneity in relation to free volume and relaxation dynamics in organic glass-formers: oligomeric cis-1,4-poly(isoprene). Phys Chem Chem Phys 2018; 19:15215-15226. [PMID: 28561833 DOI: 10.1039/c7cp00446j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Herein, a combined study of the molecular rotation dynamics and free volume in cis-1,4-poly(isoprene) using two external probing techniques via ESR and PALS together with relaxation dynamics of the host medium via BDS is presented. The spectral evolution of the spin probe TEMPO from simulations over a wide range from 100 K up to 300 K exhibits three different regions of its correlation time consisting of a slow regime at low temperatures followed by the molecular dynamic heterogeneity zone from T = T = 155 K = 0.82 × T up to Tc ≅ 236 K = 1.26 × T and ending with a fast regime at high temperatures with the further characteristic ESR temperatures, T = 186 K ≅ T and T = 260 K. These are in close coincidence with four characteristic PALS temperatures: T = 160 K, T = 190 K, T = 227 K, and T = 263 K. Finally, using BDS, we revealed that the high-frequency features of the structural relaxation of 1,4-PIP 0.8k were related to the observed effects in the ESR and PALS response of the liquid state.
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Affiliation(s)
- H Švajdlenková
- Department of Structure and Physical Properties, Polymer Institute of SAS, Dúbravská cesta 9, SK-845 41 Bratislava, Slovakia.
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97
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Higler R, Krausser J, van der Gucht J, Zaccone A, Sprakel J. Linking slow dynamics and microscopic connectivity in dense suspensions of charged colloids. SOFT MATTER 2018; 14:780-788. [PMID: 29302676 DOI: 10.1039/c7sm01781b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The quest to unravel the nature of the glass transition, where the viscosity of a liquid increases by many orders of magnitude, while its static structure remains largely unaffected, remains unresolved. While various structural and dynamical precursors to vitrification have been identified, a predictive and quantitative description of how subtle changes at the microscopic scale give rise to the steep growth in macroscopic viscosity is missing. It was recently proposed that the presence of long-lived bonded structures within the liquid may provide the long-sought connection between local structure and global dynamics. Here we directly observe and quantify the connectivity dynamics in liquids of charged colloids en route to vitrification using three-dimensional confocal microscopy. We determine the dynamic structure from the real-space van Hove correlation function and from the particle trajectories, providing upper and lower bounds on connectivity dynamics. Based on these data, we extend Dyre's model for the glass transition to account for particle-level structural dynamics; this results in a microscopic expression for the slowing down of relaxations in the liquid that is in quantitative agreement with our experiments. These results indicate how vitrification may be understood as a dynamical connectivity transition with features that are strongly reminiscent of rigidity percolation scenarios.
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Affiliation(s)
- Ruben Higler
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, Wageningen, The Netherlands.
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98
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Wong K, Krishnan RP, Chen C, Du Q, Yu D, Lu Z, Samwer K, Chathoth SM. The role of local-geometrical-orders on the growth of dynamic-length-scales in glass-forming liquids. Sci Rep 2018; 8:2025. [PMID: 29386575 PMCID: PMC5792601 DOI: 10.1038/s41598-018-20470-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/17/2018] [Indexed: 11/09/2022] Open
Abstract
The precise nature of complex structural relaxation as well as an explanation for the precipitous growth of relaxation time in cooling glass-forming liquids are essential to the understanding of vitrification of liquids. The dramatic increase of relaxation time is believed to be caused by the growth of one or more correlation lengths, which has received much attention recently. Here, we report a direct link between the growth of a specific local-geometrical-order and an increase of dynamic-length-scale as the atomic dynamics in metallic glass-forming liquids slow down. Although several types of local geometrical-orders are present in these metallic liquids, the growth of icosahedral ordering is found to be directly related to the increase of the dynamic-length-scale. This finding suggests an intriguing scenario that the transient icosahedral connectivity could be the origin of the dynamic-length-scale in metallic glass-forming liquids.
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Affiliation(s)
- Kaikin Wong
- Department of Physics, City University of Hong Kong, Kowloon Tong, Hong Kong, P. R. China
| | - Rithin P Krishnan
- Department of Physics, City University of Hong Kong, Kowloon Tong, Hong Kong, P. R. China
| | - Changjiu Chen
- Department of Physics, City University of Hong Kong, Kowloon Tong, Hong Kong, P. R. China
| | - Qing Du
- State Key Laboratory for Advanced Metals and Materials, University of Science and Technology, Beijing, 100083, P. R. China
| | - Dehong Yu
- Australian Nuclear Science and Technology Organization, Lucas Height, 2234, Australia
| | - Zhaoping Lu
- State Key Laboratory for Advanced Metals and Materials, University of Science and Technology, Beijing, 100083, P. R. China
| | - K Samwer
- I. Physik Institute, University of Goettingen, Goettingen, Germany
| | - Suresh M Chathoth
- Department of Physics, City University of Hong Kong, Kowloon Tong, Hong Kong, P. R. China.
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99
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Measurements of growing surface tension of amorphous-amorphous interfaces on approaching the colloidal glass transition. Nat Commun 2018; 9:397. [PMID: 29374262 PMCID: PMC5786034 DOI: 10.1038/s41467-018-02836-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 01/03/2018] [Indexed: 11/18/2022] Open
Abstract
There is mounting evidence indicating that relaxation dynamics in liquids approaching their glass transition not only become increasingly cooperative, but the relaxing regions also become more compact in shape. Of the many theories of the glass transition, only the random first-order theory—a thermodynamic framework—anticipates the surface tension of relaxing regions to play a role in deciding both their size and morphology. However, owing to the amorphous nature of the relaxing regions, even the identification of their interfaces has not been possible in experiments hitherto. Here, we devise a method to directly quantify the dynamics of amorphous–amorphous interfaces in bulk supercooled colloidal liquids. Our procedure also helped unveil a non-monotonic evolution in dynamical correlations with supercooling in bulk liquids. We measure the surface tension of the interfaces and show that it increases rapidly across the mode-coupling area fraction. Our experiments support a thermodynamic origin of the glass transition. The existence of interfaces, separating distinct relaxing regions, has been predicted in glass theory, but a direct proof remains challenging due to the amorphous nature of glasses. Ganapathi et al. identify and measure the surface tension of these interfaces in bulk supercooled colloidal liquids.
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100
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Ingebrigtsen TS, Tanaka H. Structural predictor for nonlinear sheared dynamics in simple glass-forming liquids. Proc Natl Acad Sci U S A 2018; 115:87-92. [PMID: 29247052 PMCID: PMC5776798 DOI: 10.1073/pnas.1711655115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glass-forming liquids subjected to sufficiently strong shear universally exhibit striking nonlinear behavior; for example, a power-law decrease of the viscosity with increasing shear rate. This phenomenon has attracted considerable attention over the years from both fundamental and applicational viewpoints. However, the out-of-equilibrium and nonlinear nature of sheared fluids have made theoretical understanding of this phenomenon very challenging and thus slower to progress. We find here that the structural relaxation time as a function of the two-body excess entropy, calculated for the extensional axis of the shear flow, collapses onto the corresponding equilibrium curve for a wide range of pair potentials ranging from harsh repulsive to soft and finite. This two-body excess entropy collapse provides a powerful approach to predicting the dynamics of nonequilibrium liquids from their equilibrium counterparts. Furthermore, the two-body excess entropy scaling suggests that sheared dynamics is controlled purely by the liquid structure captured in the form of the two-body excess entropy along the extensional direction, shedding light on the perplexing mechanism behind shear thinning.
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Affiliation(s)
- Trond S Ingebrigtsen
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, Tokyo 153-8505, Japan
| | - Hajime Tanaka
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, Tokyo 153-8505, Japan
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