Static and dynamic correlation lengths in supercooled polymers

Balbuena, Cristian; Gianetti, Melisa Mariel; Soulé, Ezequiel Rodolfo

doi:10.1063/1.5091682

Cited by 4 publications

(5 citation statements)

References 53 publications

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“…Alternatively, by observing the behavior of incoherent intermediate scattering function, two relaxation mechanisms can be observed for temperatures below T A : the β at short times and the alpha at long times. From our previous work [39] it can be noted that both functions manifest the change in behaviour described above at a temperature close to T A . In what follows, we characterized the heterogeneous dynamics by two functions that are typically used to describe it.…”

Section: Resultssupporting

confidence: 62%

“…In previous works, we have have found, using ICEM, regions where the particles are strongly dynamically connected, as defined by a high value of Pearson's correlation coefficient; these particles also form clusters, but they are not the same than those formed by mobile or immobile particles [38]. In addition, we showed that a dynamic correlation length, defined from the decay of Pearson's correlation coefficient, shows a linear relation with a static correlation length in the whole temperature range, unlike typical fourpoint correlation lengths which display this linearity only for high temper atures [39].…”

Section: Introductionmentioning

confidence: 60%

“…Finally, this can be compared with the number of correlated particles defined from a purely structural or static correlation. To this end, the number of correlated particles calculated with the Point-to-Set (PtS) method is extracted from simulations performed in our previous work [39]. We calculate the number of correlated particles according to the PtS method by calculating: N corr−P tS (T ) = 4/3πρ(T )(ξ P ts (T )) 3 , where ξ P ts (T ) is the static correlation length of a spherical cluster from PtS method.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

See 2 more Smart Citations

An alternative approach to evidence the structural conditioning in the dynamic slowdown in a polymer glass-former

Balbuena¹,

Soulé²

2019

J. Phys.: Condens. Matter

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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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Section: Resultssupporting

confidence: 62%

Section: Introductionmentioning

confidence: 60%

Section: Accepted Manuscriptmentioning

confidence: 99%

See 1 more Smart Citation

An alternative approach to evidence the structural conditioning in the dynamic slowdown in a polymer glass-former

Balbuena¹,

Soulé²

2019

J. Phys.: Condens. Matter

Self Cite

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“…The prevailing methodology to detect spatial correlations in glassy systems is suggested by the random firstorder theory (RFOT) [8][9][10]: pinning a subset of particles in the equilibrium fluid, one examines how the configuration of the rest of particles is influenced [11][12][13][14][15]. While this point-to-set (PTS) protocol is designed to keep the static properties of the system in equilibrium, it represents a strong perturbation of the dynamics [16,17]: The freezing of some particles can be viewed as imposing a zero-temperature region and hence a strong temperature gradient, yet the associated linear-response regime shrinks to zero at the glass transition [18].…”

mentioning

confidence: 99%

Nonmonotonic Dynamical Correlations beneath the Surface of Glass-Forming Liquids

2022

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Collective motion over increasing length scales is a signature of the vitrification process of liquids. We demonstrate how distinct static and dynamic length scales govern the dynamics of vitrifying films. In contrast to a monotonically growing static correlation length, the dynamical correlation length that measures the extent of surface-dynamics acceleration into the bulk, displays a striking non-monotonic temperature evolution that is robust also against changes in detailed interatomic interaction. This non-monotonic change defines a cross-over temperature T * that is distinct from the critical temperature Tc of mode-coupling theory (MCT). We connect this non-monotonic change to a morphological change of cooperative rearrangement regions (CRR) of fast particles, and to the point where the decoupling of fast-particle motion from the bulk relaxation is most sensitive to fluctuations. We propose a rigorous definition of this new cross-over temperature T * within a recent extension of MCT, the stochastic β-relaxation theory (SBR).

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“…The prevailing methodology to detect spatial correlations in glassy systems is suggested by the random first-order theory (RFOT) [10][11][12]: pinning a subset of particles in the equilibrium fluid, one examines how the configuration of the rest of particles is influenced [13][14][15][16]. While this point-to-set (PTS) protocol is designed to keep the static properties of the system in equilibrium, it represents a strong perturbation of the dynamics [17]:…”

mentioning

confidence: 99%

Non-monotonic dynamic correlations beneath the surface of glass-forming liquids

Peng¹,

Liu²,

Voigtmann³

2021

Preprint

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Collective motion over increasing length scales is a signature of the vitrification process of liquids. We demonstrate how distinct static and dynamic length scales govern the dynamics of vitrifying films. In contrast to a monotonically growing static correlation length, the dynamic correlation length that measures the extent of surface-dynamics acceleration into the bulk, displays a striking non-monotonic temperature evolution that is robust also against changes in detailed interatomic interaction. This non-monotonic change defines a cross-over temperature T * that is distinct from the critical temperature Tc of mode-coupling theory (MCT). We connect this non-monotonic change to a cross-over from mean-field like liquid dynamics to glass-like dynamics that is signalled by a morphological change of cooperative rearrangement regions (CRR) of fast particles, and as the point where fast-particle motion decouples from structural relaxation. We propose a rigorous definition of this new cross-over temperature T * within a recent extension of MCT, the stochastic β-relaxation theory (SBR).

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Static and dynamic correlation lengths in supercooled polymers

Cited by 4 publications

References 53 publications

An alternative approach to evidence the structural conditioning in the dynamic slowdown in a polymer glass-former

An alternative approach to evidence the structural conditioning in the dynamic slowdown in a polymer glass-former

Nonmonotonic Dynamical Correlations beneath the Surface of Glass-Forming Liquids

Non-monotonic dynamic correlations beneath the surface of glass-forming liquids

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