Relaxation Processes in Liquids and Glass-Forming Systems: What Can We Learn by Comparing Neutron Scattering and Dielectric Spectroscopy Results?

Arbe, Arantxa; Colmenero, Juan

doi:10.1007/978-3-319-72706-6_8

Cited by 2 publications

(2 citation statements)

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“…The meaning of the Q * is not yet fully understood. In the case of a simple diffusive process, a simple approach based on molecular hydrodynamics and a molecular treatment of dielectric results allowed expressing Q * in terms of a many-body magnitudea generalized Kirkwood parameterand a single-molecule magnitudethe hydrodynamic radius. , The generalization to the case of polymeric materials showing anomalous diffusion is not straightforward, as recently shown . A connection of Q * with structural parameters like the position of the inter-main-chain correlation peak of the structure factor, Q max was also explored in that work.…”

Section: Discussionmentioning

confidence: 99%

“…23,24 The generalization to the case of polymeric materials showing anomalous diffusion is not straightforward, as recently shown. 39 A connection of Q* with structural parameters like the position of the inter-mainchain correlation peak of the structure factor, Q max was also explored in that work. Main-chain polymers (without side groups) or polymers with only methyl groups as side groups present rather similar values of Q* ≈ 0.9 Å −1 independently of the value of Q max .…”

Section: ■ Discussionmentioning

confidence: 99%

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Applying Polymer Blend Dynamics Concepts to a Simplified Industrial System. A Combined Effort by Dielectric Spectroscopy and Neutron Scattering

et al. 2018

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In this work we apply the methodology and concepts developed over the last years for the study of segmental dynamics on miscible polymer blends to the investigation of a blend made of styrene-butadiene rubber (SBR) and an oligomer of polystyrene (PS), as an example of simplified industrial system. In this way we obtain detailed information about the segmental dynamics of both components within the blend. To this end, a judicious combination of broad-band dielectric spectroscopy (BDS) and quasi-elastic neutron scattering (QENS) results on deuterium-labelled blends was required. Difficulties on the comparison between isotopically different samples arose due to changes in polymer microstructure associated with the obtention of deuterated polymers. Nevertheless, the strategy for data analysis developed in this work made it possible to readily resolve the components' segmental dynamics of the investigated mixtures. It was found that Gaussian distributions of the components' effective glass-transition temperatures provide a very good description of all the experimental data collected in the SBR/PS (50/50 wt%) mixtures over the whole accessible temperature range, not only by BDS and QENS but also those obtained by differential scanning calorimetry and by neutron elastic-fixed-window-scans experiments.

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Section: Discussionmentioning

confidence: 99%

Section: ■ Discussionmentioning

confidence: 99%

Applying Polymer Blend Dynamics Concepts to a Simplified Industrial System. A Combined Effort by Dielectric Spectroscopy and Neutron Scattering

et al. 2018

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Experimental evidence of mosaic structure in strongly supercooled molecular liquids

et al. 2021

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When a liquid is cooled to produce a glass its dynamics, dominated by the structural relaxation, become very slow, and at the glass-transition temperature Tg its characteristic relaxation time is about 100 s. At slightly elevated temperatures (~1.2 Tg) however, a second process known as the Johari-Goldstein relaxation, βJG, decouples from the structural one and remains much faster than it down to Tg. While it is known that the βJG-process is strongly coupled to the structural relaxation, its dedicated role in the glass-transition remains under debate. Here we use an experimental technique that permits us to investigate the spatial and temporal properties of the βJG relaxation, and give evidence that the molecules participating in it are highly mobile and spatially connected in a system-spanning, percolating cluster. This correlation of structural and dynamical properties provides strong experimental support for a picture, drawn from theoretical studies, of an intermittent mosaic structure in the deeply supercooled liquid phase.

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Relaxation Processes in Liquids and Glass-Forming Systems: What Can We Learn by Comparing Neutron Scattering and Dielectric Spectroscopy Results?

Cited by 2 publications

References 99 publications

Applying Polymer Blend Dynamics Concepts to a Simplified Industrial System. A Combined Effort by Dielectric Spectroscopy and Neutron Scattering

Applying Polymer Blend Dynamics Concepts to a Simplified Industrial System. A Combined Effort by Dielectric Spectroscopy and Neutron Scattering

Experimental evidence of mosaic structure in strongly supercooled molecular liquids

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