Glassy dynamics, spinodal fluctuations, and the kinetic limit of hard-rod nucleation

TL;DR

This paper uses simulations to explore the dynamic regimes and kinetic limits of nucleation in supersaturated hard-rod fluids, revealing how different supersaturation levels lead to various arrested states and phase transitions.

Contribution

It identifies three distinct dynamic regimes in supersaturated hard-rod fluids and elucidates how spinodal fluctuations and glassy dynamics limit nucleation.

Findings

Multiple nucleation regimes identified at different supersaturations

Suppression of smectic phase formation by spinodal instability

Glassy dynamics and spinodal fluctuations constrain nucleation

Abstract

Using simulations we identify three dynamic regimes in supersaturated isotropic fluid states of short hard rods: (i) for moderate supersaturations we observe nucleation of multi-layered crystalline clusters; (ii) at higher supersaturation, we find nucleation of small crystallites which arrange into long-lived locally favored structures that get kinetically arrested, while (iii) at even higher supersaturation the dynamic arrest is due to the conventional cage-trapping glass transition. For longer rods we find that the formation of the (stable) smectic phase out of a supersaturated isotropic state is strongly suppressed by an isotropic-nematic spinodal instability that causes huge spinodal-like orientation fluctuations with nematic clusters diverging in size. Our results show that glassy dynamics and spinodal instabilities set kinetic limits to nucleation in a highly supersaturated hard-rod fluids.