Heterophase fluctuations in supercooled liquids and polymers

Fischer, Erhard W.; Bakaı̆, A. S.; Patkowski, A.; Steffen, Werner; Reinhardt, L.

doi:10.1016/s0022-3093(02)01510-7

Cited by 47 publications

(40 citation statements)

References 44 publications

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“…In this formulation of the HPFM [1,3,6], solidlike fluctuons having the averaged SRO and thermodynamic properties are considered. In this case, the order parameters of the liquid are fractions of the solid-like and fluid-like fluctuons, c s and c f , respectively.…”

Section: Glass Transition In Hpfm Modelmentioning

confidence: 99%

“…A model of the cooperative relaxational dynamics of the heterophase liquids was proposed in [2,3]. It is based on a simple physical idea.…”

Section: The Cooperative Relaxational Dynamics Of the Heterophase Liqmentioning

confidence: 99%

“…In [2,3] these equations were successfully used to fit the relaxation rate and its derivatives of salol in the glass transition temperature range. Reliability of the developed α-relaxation model was checked by fitting the experimental data for many other liquids.…”

Section: The Cooperative Relaxational Dynamics Of the Heterophase Liqmentioning

confidence: 99%

“…The heterophase fluctuations model (HPFM) is based on the idea of heterophase structure of glass forming liquids [1][2][3][4][5]. Consecutive consideration shows that in a heterophase state (HPS), molecular clusters (fluctuons) of specified short-range order (SRO) are statistically significant entities rather than single molecules.…”

Section: Introductionmentioning

confidence: 99%

“…The model of the cooperative relaxation dynamics of HPS developed in [2,3] describes the α-relaxation rate in terms of the free energy. The developed theory is a proper base for the analysis of experimental data on thermodynamics, structure and cooperative relaxation of the glass-forming liquids [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

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On the heterophase liquid thermodynamics and cooperative dynamics

Bakai¹

2010

Condens. Matter Phys.

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The thermodynamics and cooperative dynamics of heterophase liquid states is considered taking into account frustration and volumetric interaction of the solid-like fluctuons. It is found that the glass transition temperature range is scaled by difference of the frustration parameter and mean energy of the volumetric interaction. A model of the cooperative relaxation with finite cooperatively rearranging domains is considered. The fictitious Kauzmann and Vogel-Fulcher temperatures are determined. It is found that they are close to a proper accuracy. Correlation of the temperatures of glass transition, Vogel-Fulcher and "ideal" glass transition (as it is determined in the mode coupling model) is considered too.

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Section: Glass Transition In Hpfm Modelmentioning

confidence: 99%

“…A model of the cooperative relaxational dynamics of the heterophase liquids was proposed in [2,3]. It is based on a simple physical idea.…”

Section: The Cooperative Relaxational Dynamics Of the Heterophase Liqmentioning

confidence: 99%

Section: The Cooperative Relaxational Dynamics Of the Heterophase Liqmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the heterophase liquid thermodynamics and cooperative dynamics

Bakai¹

2010

Condens. Matter Phys.

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Fragile Glass Formers: Evidence for a New Paradigm, and a New Relation to Strong Liquids

Angell¹

2012

Structural Glasses and Supercooled Liquids

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The missing parameter in rheology: hidden solid‐like correlations in viscous liquids, polymer melts and glass formers

Noirez

Baroni

Mendil‐Jakani

2009

Polymer International

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BACKGROUND: Determination of dynamic relaxation consists of measuring the viscous and the elastic components of a material by generally applying a small (oscillatory) deformation. The shear stress is transmitted to the material via contact with a substrate. Dating at least back to Stokes, the no‐slip boundary condition between the fluid and the substrate is supposed to be fulfilled during this measurement. We show that the viscoelastic parameters of fluids are usually not determined under no‐slip boundary conditions and do not originate from the first linear regime. Viscous and viscoelastic fluids (entangled and unentangled polymers, glass formers) measured under no‐slip conditions exhibit a fundamentally different response with a dominant terminal solid‐like response. RESULTS: We show that the terminal behaviour of fluids such as liquid polymers or glass formers measured at the sub‐millimetre scale and far above the glass transition is not viscous but solid‐like. Instead of a viscoelastic behaviour scaling as ω and ω2 (ω is the frequency) for the viscous and the elastic moduli, respectively, the dynamic response is simplified; for low gap thickness, both viscous and elastic moduli are invariant with respect to the frequency (with the elastic modulus being larger than the viscous modulus) and enhanced by two to four orders of magnitude compared to the conventional viscoelastic response. Over a critical strain amplitude, the solid‐like response decreases and is progressively replaced by the conventional viscoelastic behaviour. We discuss the implications of this observation and reconsider the assumptions inherent to a rheology measurement. CONCLUSION: The identification of so far neglected macroscopic elasticity in the fluidic state far above the glass transition temperature in entangled and unentangled polymers and glass formers shows that the liquid state is dominated by long range intermolecular interactions. This information is fundamental to understand and to foresee dynamic behaviour; it sheds further light on nonlinear phenomena such as large time scale relaxations, rheo‐thinning, violation of the no‐slip boundary condition and spectacular shear‐induced instabilities (spurt effect, ‘shark‐skin’ instabilities, gross melt fracture, etc.) that are unpredictable in the frame of the conventional viscoelastic approach. It also implies that the viscoelastic times (reptation, Rouse) in polymers are not the longest relaxation times of these materials. Copyright © 2009 Society of Chemical Industry

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Heterophase fluctuations in supercooled liquids and polymers

Cited by 47 publications

References 44 publications

On the heterophase liquid thermodynamics and cooperative dynamics

On the heterophase liquid thermodynamics and cooperative dynamics

Fragile Glass Formers: Evidence for a New Paradigm, and a New Relation to Strong Liquids

The missing parameter in rheology: hidden solid‐like correlations in viscous liquids, polymer melts and glass formers

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