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Chaudhuri M, Allahyarov E, Löwen H, Egelhaaf SU, Weitz DA. Triple Junction at the Triple Point Resolved on the Individual Particle Level. PHYSICAL REVIEW LETTERS 2017; 119:128001. [PMID: 29341657 DOI: 10.1103/physrevlett.119.128001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Indexed: 06/07/2023]
Abstract
At the triple point of a repulsive screened Coulomb system, a fcc crystal, a bcc crystal, and a fluid phase coexist. At their intersection, these three phases form a liquid groove, the triple junction. Using confocal microscopy, we resolve the triple junction on a single-particle level in a model system of charged PMMA colloids in a nonpolar solvent. The groove is found to be extremely deep and the incommensurate solid-solid interface to be very broad. Thermal fluctuations hence appear to dominate the solid-solid interface. This indicates a very low interfacial energy. The fcc-bcc interfacial energy is quantitatively determined based on Young's equation and, indeed, it is only about 1.3 times higher than the fcc-fluid interfacial energy close to the triple point.
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Affiliation(s)
- M Chaudhuri
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
- Institute for Theoretical Physics II: Soft Matter, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - E Allahyarov
- Institute for Theoretical Physics II: Soft Matter, Heinrich Heine University, 40225 Düsseldorf, Germany
- Theoretical Department, Joint Institute for High Temperatures, Russian Academy of Sciences (IVTAN), Moscow 125412, Russia
| | - H Löwen
- Institute for Theoretical Physics II: Soft Matter, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - S U Egelhaaf
- Condensed Matter Physics Laboratory, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - D A Weitz
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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Westermeier F, Pennicard D, Hirsemann H, Wagner UH, Rau C, Graafsma H, Schall P, Lettinga MP, Struth B. Connecting structure, dynamics and viscosity in sheared soft colloidal liquids: a medley of anisotropic fluctuations. SOFT MATTER 2016; 12:171-80. [PMID: 26451659 DOI: 10.1039/c5sm01707f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Structural distortion and relaxation are central to any liquid flow. Their full understanding requires simultaneous probing of the mechanical as well as structural and dynamical response. We provide the first full dynamical measurement of the transient structure using combined coherent X-ray scattering and rheology on electrostatically interacting colloidal fluids. We find a stress overshoot during the start-up of shear which is due to the strong anisotropic overstretching and compression of nearest-neighbor distances. The rheological response is reflected in uncorrelated entropy-driven intensity fluctuations. While the structural distortion under steady shear is well described by Smoluchowski theory, we find an increase of the particle dynamics beyond the trivial contribution of flow. After the cessation of shear, the full fluid microstructure and dynamics are restored, both on the structural relaxation timescale. We thus find unique structure-dynamics relations in liquid flow, responsible for the macroscopic rheological behavior of the system.
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Affiliation(s)
- Fabian Westermeier
- Max Planck Institute for the Structure and Dynamics of Matter, CFEL, Luruper Chaussee 149, 22761 Hamburg, Germany.
| | - David Pennicard
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Helmut Hirsemann
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Ulrich H Wagner
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Christoph Rau
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Heinz Graafsma
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Peter Schall
- Van der Waals-Zeeman Institute, University of Amsterdam, POSTBUS 94485, 1090 GL Amsterdam, The Netherlands
| | - M Paul Lettinga
- Forschungszentrum Jülich, Institute of Complex Systems (ICS-3), 52425 Jülich, Germany.
| | - Bernd Struth
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
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Binder K, Virnau P, Statt A. Perspective: The Asakura Oosawa model: A colloid prototype for bulk and interfacial phase behavior. J Chem Phys 2014; 141:140901. [DOI: 10.1063/1.4896943] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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Eberle APR, Martys N, Porcar L, Kline SR, George WL, Kim JM, Butler PD, Wagner NJ. Shear viscosity and structural scalings in model adhesive hard-sphere gels. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:050302. [PMID: 25353728 DOI: 10.1103/physreve.89.050302] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Indexed: 06/04/2023]
Abstract
We present experiments and simulations that show a fundamental scaling for both the rheology and microstructure of flowing gels. Unique flow-SANS measurements demonstrate that the structure orients along both the neutral and compression axis. We quantify the anisotropy using a single parameter, α, that scales by a dimensionless number, M^{'}, that arises from a force balance on a particle. Simulations support the scalings and confirm the results are independent of the shape and range of the potential suggesting a universal for colloidal gels with short-ranged attractions.
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Affiliation(s)
- Aaron P R Eberle
- NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA and Center for Neutron Science and Department of Chemical & Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA
| | - Nicos Martys
- Building and Fire Research Laboratory, NIST, Gaithersburg, Maryland 20899, USA
| | - Lionel Porcar
- Large Scale Structures Group, Institut Laue-Langevin, Grenoble, France
| | - Steven R Kline
- NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
| | - William L George
- NIST Information Technology Laboratory, Gaithersburg, Maryland 20899, USA
| | - Jung M Kim
- Center for Neutron Science and Department of Chemical & Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA
| | - Paul D Butler
- NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
| | - Norman J Wagner
- Center for Neutron Science and Department of Chemical & Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA
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Smith THR, Vasilyev O, Abraham DB, Maciołek A, Schmidt M. Interfaces in driven Ising models: shear enhances confinement. PHYSICAL REVIEW LETTERS 2008; 101:067203. [PMID: 18764496 DOI: 10.1103/physrevlett.101.067203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 06/12/2008] [Indexed: 05/26/2023]
Abstract
We use a phase-separated driven two-dimensional Ising lattice gas to study fluid interfaces exposed to shear flow parallel to the interface. The interface is stabilized by two parallel walls with opposing surface fields, and a driving field parallel to the walls is applied which (i) either acts locally at the walls or (ii) varies linearly with distance across the strip. Using computer simulations with Kawasaki dynamics, we find that the system reaches a steady state in which the magnetization profile is the same as that in equilibrium, but with a rescaled length implying a reduction of the interfacial width. An analogous effect was recently observed in sheared phase-separated colloidal dispersions. Pair correlation functions along the interface decay more rapidly with distance under drive than in equilibrium and for cases of weak drive, can be rescaled to the equilibrium result.
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Affiliation(s)
- Thomas H R Smith
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
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Yethiraj A. Tunable colloids: control of colloidal phase transitions with tunable interactions. SOFT MATTER 2007; 3:1099-1115. [PMID: 32900031 DOI: 10.1039/b704251p] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Systems of spherical colloidal particles mimic the thermodynamics of atomic crystals. Control of interparticle interactions in colloids, which has recently begun to be extensively exploited, gives rise to rich phase behaviours as well as crystal structures with nanoscale and micron-scale lattice spacings. This provides model systems in which to study fundamental problems in condensed matter physics, such as the dynamics of crystal nucleation and melting, and the nature of the glass transition, at experimentally accessible lengthscales and timescales. Tunable control of these interactions provides reversible control. This will enable quantitative studies of phase transition kinetics as well as the creation of advanced materials with switchability of function and properties.
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Affiliation(s)
- Anand Yethiraj
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, Canada.
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