Eshelby description of highly viscous flow III

TL;DR

This paper extends the Eshelby model to predict different viscosities in stationary and alternating flows, linking structural dynamics with experimental data and enabling estimation of molecular domain sizes.

Contribution

It introduces a new Ansatz connecting barrier density increase with structural alternatives, allowing estimation of Eshelby domain sizes from relaxation and calorimetric data.

Findings

Predicted a factor of two difference in viscosities for different flow types.

Linked barrier density increase to structural complexity via Adam-Gibbs theory.

Provided a method to estimate Eshelby domain size from experimental data.

Abstract

The recent Eshelby description of the highly viscous flow leads to the prediction of a factor of two different viscosities in stationary and alternating flow, in agreement with experimental evidence. The Kohlrausch barrier density increase with increasing barrier height finds a physical justification in the Adam-Gibbs increase of the number of structural alternatives of the Eshelby region with its increasing size. The new Ansatz allows to determine the number of atoms or molecules in the rearranging Eshelby domains from a combination of dynamic shear relaxation and calorimetric data.