Multiple reentrant glass transitions in confined hard-sphere glasses

TL;DR

This study reveals multiple reentrant glass transitions in confined hard-sphere glasses when the wall separation is varied, combining simulations and theoretical predictions, with implications for micro- and nanotechnology applications.

Contribution

It demonstrates the occurrence of multiple reentrant glass transitions in confined hard-sphere fluids, supported by simulations and theoretical models, in a regime relevant for experimental and technological applications.

Findings

Multiple reentrant glass transitions observed with changing wall separation.

Reentrant phenomena persist under constant chemical potential.

Results align with density functional and mode-coupling theory predictions.

Abstract

Glass forming liquids exhibit a rich phenomenology upon confinement. This is often related to the effects arising from wall-fluid interactions. Here we focus on the interesting limit where the separation of the confining walls becomes of the order of a few particle diameters. For a moderately polydisperse, densely packed hard-sphere fluid confined between two smooth hard walls, we show via event-driven molecular dynamics simulations the emergence of a multiple reentrant glass transition scenario upon a variation of the wall separation. Using thermodynamic relations, this reentrant phenomenon is shown to persist also under constant chemical potential. This allows straightforward experimental investigation and opens the way to a variety of applications in micro- and nanotechnology, where channel dimensions are comparable to the size of the contained particles. The results are in-line with theoretical predictions obtained by a combination of density functional theory and the mode-coupling theory of the glass transition.