Direct observation of molecular cooperativity near the glass transition

  title={Direct observation of molecular cooperativity near the glass transition},
  author={Ezequiel Vidal Russell and Nathan Eli Israeloff},
The increasingly sluggish response of a supercooled liquid as it nears its glass transition (for example, refrigerated honey) is prototypical of glassy dynamics found in proteins, neural networks and superconductors. The notion that molecules rearrange cooperatively has long been postulated to explain diverging relaxation times and broadened (non-exponential) response functions near the glass transition. Recently, cooperativity was observed and analysed in colloid glasses and in simulations of… Expand
The shapes of cooperatively rearranging regions in glass-forming liquids
The cooperative rearrangement of groups of many molecules has long been thought to underlie the dramatic slowing of liquid dynamics on cooling towards the glassy state. For instance, there existsExpand
Molecular cooperativity in the dynamics of glass-forming systems: a new insight.
This work estimates the length scale of molecular cooperativity xi for many glass-forming systems from the collective vibrations (the so-called boson peak) and demonstrates that xi directly correlates to the dependence of the structural relaxation on volume. Expand
Cooperative motions in supercooled liquids and glasses
Why glasses behave like solids in the absence of their having any long range structural order, is a fundamental problem of statistical physics, one that has been actively researched for more than 80Expand
Dynamical heterogeneity of the glassy state.
Dynamical heterogeneities in equilibrated supercooled liquids and in the nonequilibrium glassy state are compared within the framework of the random first order transition theory to explain in a unified way recent experimental observations that have been interpreted as coming from there being two distinct equilibration mechanisms in glasses. Expand
Single molecules reveal the dynamics of heterogeneities in a polymer at the glass transition.
A model for glass dynamics is presented in which each rearrangement in one region causes a random change in the barrier height for subsequent rearrangements in a neighboring region, which reproduces the statistics of the experimentally observed waiting time sequences. Expand
On the mechanism of activated transport in glassy liquids.
It is confirmed that the entropic droplet picture is indeed not only internally consistent but is also fully constructive, consistent with the apparent success of its many quantitative predictions. Expand
Relation between concentration fluctuations and dynamical heterogeneities in binary glass-forming liquids: A molecular dynamics simulation study.
In molecular dynamics simulations of binary glass-forming liquids with high dynamical contrast, the slow species sustains the microphase segregation in the mixture, while the fast component moves along the concentration and mobility gradients, leading to remarkable dynamical features. Expand
Dynamic Heterogeneity and Cooperative Length Scale at Dynamic Glass Transition in Glass Forming Liquids
Understanding the evolution of the cooperative molecular mobility as a function of time and temperature remains an unsolved question in condensed matter research. However, recently great advancesExpand
Theory of structural glasses and supercooled liquids.
We review the random first-order transition theory of the glass transition, emphasizing the experimental tests of the theory. Many distinct phenomena are quantitatively predicted or explained by theExpand
Vibrational dynamics as an indicator of short-time interactions in glass-forming liquids and their possible relation to cooperativity
We report on a vibrational dynamics study of two glass-forming liquids over a wide temperature range including the glassy, supercooled, and molten state. Our aim is to find possible sensitiveExpand


Growing range of correlated motion in a polymer melt on cooling towards the glass transition
Many liquids cooled to low temperatures form glasses (amorphous solids) instead of crystals. As the glass transition is approached, molecules become localized and relaxation times increase by manyExpand
Fragilities of liquids predicted from the random first order transition theory of glasses.
  • X. Xia, P. Wolynes
  • Materials Science, Medicine
  • Proceedings of the National Academy of Sciences of the United States of America
  • 2000
The wide variety of kinetic behavior in liquids of quite disparate chemical nature reflects quantitative rather than qualitative differences in their energy landscapes. Expand
Formation of Glasses from Liquids and Biopolymers
The onset of a sharp change in ddT( is the Debye-Waller factor and T is temperature) in proteins, which is controversially indentified with the glass transition in liquids, is shown to be general for glass formers and observable in computer simulations of strong and fragile ionic liquids, where it proves to be close to the experimental glass transition temperature. Expand
On the Temperature Dependence of Cooperative Relaxation Properties in Glass‐Forming Liquids
A molecular‐kinetic theory, which explains the temperature dependence of relaxation behavior in glass‐forming liquids in terms of the temperature variation of the size of the cooperativelyExpand
Spatially heterogeneous dynamics in supercooled liquids.
  • M. Ediger
  • Materials Science, Medicine
  • Annual review of physical chemistry
  • 2000
Although it has long been recognized that dynamics in supercooled liquids might be spatially heterogeneous, only in the past few years has clear evidence emerged to support this view. As a liquid isExpand
Three-dimensional direct imaging of structural relaxation near the colloidal glass transition
Confocal microscopy was used to directly observe three-dimensional dynamics of particles in colloidal supercooled fluids and colloidal glasses; connected clusters of these mobile particles could be identified; and the cluster size distribution, structure, and dynamics were investigated. Expand
Effect of Free Surfaces on the Glass Transition Temperature of Thin Polymer Films.
The concept of cooperative rearrangement was introduced in an attempt to unify these two views of the glass transition by demonstrating that such cooperativity, coupled with a thermodynamic glass transition, resulted naturally insystem dynamics such as those described by the WLFequation for temperatures near freezing. Expand
Nature of the Non-exponential Primary Relaxation in Structural Glass-formers Probed by Dynamically Selective Experiments
Several experimental methods feature the potential to distinguish between slow and fast contributions to the non-exponential, ensemble averaged primary response in glass-forming materials. Some ofExpand
Nanometer Scale Dielectric Fluctuations at the Glass Transition
Using non-contact scanning probe microscopy (SPM) techniques, dielectric properties were studied on 50 nanometer length scales in poly-vinyl-acetate (PVAc) films in the vicinity of the glassExpand
Geometry of reorientational dynamics in supercooled poly(vinyl acetate) studied by 13C two-dimensional nuclear magnetic resonance echo experiments
A study of the reorientational segmental dynamics in supercooled poly(vinyl acetate) is presented, yielding detailed information about geometry and time scale of the motion close to the glassExpand