Waiting-time dependent non-equilibrium phase diagram of simple glass- and gel-forming liquids

TL;DR

This paper develops a theoretical framework to define and predict non-equilibrium phase diagrams of glass- and gel-forming liquids, accounting for aging and time-dependent properties using a novel non-equilibrium statistical mechanics approach.

Contribution

It introduces a new kinetic theory-based method to characterize and predict non-stationary phases and aging processes in amorphous materials from molecular interactions.

Findings

Successfully describes transient dynamic arrest in a simple model fluid.

Predicts non-equilibrium phases and aging behavior.

Provides a theoretical basis for non-stationary phase diagrams.

Abstract

Under many circumstances many soft and hard materials are present in a puzzling wealth of non-equilibrium amorphous states, whose properties are not stationary and depend on preparation. They are often summarized in unconventional "phase diagrams" that exhibit new "phases" and/or "transitions", in which the time, however, is an essential variable. This work proposes a solution to the problem of theoretically defining and predicting these non-equilibrium phases and their time-evolving phase diagrams, given the underlying molecular interactions. We demonstrate that these non-equilibrium phases and the corresponding non-stationary (i.e., aging) phase diagrams can indeed be defined and predicted using the kinetic perspective of a novel non-equilibrium statistical mechanical theory of irreversible processes. This is illustrated with the theoretical description of the transient process of dynamic arrest into non-equilibrium amorphous solid phases, of an instantaneously-quenched simple model fluid involving repulsive hard-sphere plus attractive square well pair interactions.