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Predictive relation for the ?-relaxation time of a coarse-grained polymer melt under steady shear.

ABSTRACT: We examine the influence of steady shear on structural relaxation in a simulated coarse-grained unentangled polymer melt over a wide range of temperature and shear rates. Shear is found to progressively suppress the ?-relaxation process observed in the intermediate scattering function, leading ultimately to a purely inertially dominated ?-relaxation at high shear rates, a trend similar to increasing temperature. On the basis of a scaling argument emphasizing dynamic heterogeneity in cooled liquids and its alteration under material deformation, we deduce and validate a parameter-free scaling relation for both the structural relaxation time ?? from the intermediate scattering function and the "stretching exponent" ? quantifying the extent of dynamic heterogeneity over the entire range of temperatures and shear rates that we can simulate.

SUBMITTER: Giuntoli A

PROVIDER: S-EPMC7182423 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

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Predictive relation for the α-relaxation time of a coarse-grained polymer melt under steady shear.

Giuntoli Andrea A Puosi Francesco F Leporini Dino D Starr Francis W FW Douglas Jack F JF

Science advances 20200424 17

We examine the influence of steady shear on structural relaxation in a simulated coarse-grained unentangled polymer melt over a wide range of temperature and shear rates. Shear is found to progressively suppress the α-relaxation process observed in the intermediate scattering function, leading ultimately to a purely inertially dominated β-relaxation at high shear rates, a trend similar to increasing temperature. On the basis of a scaling argument emphasizing dynamic heterogeneity in cooled liqui ...[more]

PMID: 32494635

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