Nonequilibrium thermodynamics and glassy rheology

TL;DR

This paper discusses a nonequilibrium thermodynamic framework for understanding the rheology of glassy and complex fluids, emphasizing the role of an evolving effective disorder temperature in modeling their behavior.

Contribution

It introduces a novel thermodynamic approach using an effective disorder temperature and internal variables to predict rheological responses of glassy systems.

Findings

Effective disorder temperature characterizes structural state.

Internal variables govern energy and entropy flow.

Framework successfully applied to various systems.

Abstract

Mechanically driven glassy systems and complex fluids exhibit a wealth of rheological behaviors that call for theoretical understanding and predictive modeling. A distinct feature of these nonequilibrium systems is their dynamically evolving state of structural disorder, which determines their rheological responses. Here we highlight a recently developed nonequilibrium thermodynamic framework in which the structural state is characterized by an evolving effective disorder temperature that may differ from the ordinary thermal temperature. The specific properties of each physical system of interest are described by a small set of coarse-grained internal state variables and their associated energies and entropies. The dynamics of the internal variables, together with the flow of energy and entropy between the different parts of the driven system, determine continuum-level rheological constitutive laws. We conclude with brief descriptions of several successful applications of this framework.