How a liquid becomes a glass both on cooling and on heating

TL;DR

This study investigates how a silica nanoparticle suspension undergoes glass transitions during both cooling and heating, revealing unique relaxation behaviors and comparing experimental results with theoretical models of attractive glass formation.

Contribution

It provides detailed experimental characterization of dual glass transitions in a model system with attractive interactions, linking observations to recent theoretical predictions.

Findings

Glass transition occurs on both cooling and heating.

Unusual logarithmic relaxation dynamics observed.

Comparison with theoretical models of attractive glasses.

Abstract

The onset of structural arrest and glass formation in a concentrated suspension of silica nanoparticles in a water-lutidine binary mixture near its consolute point is studied by exploiting the near-critical fluid degrees of freedom to control the strength of an attraction between particles and multispeckle x-ray photon correlation spectroscopy to determine the particles' collective dynamics. This model system undergoes a glass transition both on cooling and on heating, and the intermediate liquid realizes unusual logarithmic relaxations. How vitrification occurs for the two different glass transitions is characterized in detail and comparisons are drawn to recent theoretical predictions for glass formation in systems with attractive interactions.