Colloidal glass transition observed in confinement

TL;DR

This study demonstrates that confinement induces glassy behavior in colloidal suspensions, with slower particle dynamics and transition onset at larger scales as volume fraction increases, providing insights into glass transitions in confined systems.

Contribution

It provides direct experimental evidence of colloidal glass transition behavior under confinement using confocal microscopy.

Findings

Confinement slows down colloidal particle motion.

Glass transition behavior appears at larger scales with increased volume fraction.

Confocal microscopy enables direct observation of particle dynamics in confined geometries.

Abstract

We study a colloidal suspension confined between two quasi-parallel walls as a model system for glass transitions in confined geometries. The suspension is a mixture of two particle sizes to prevent wall-induced crystallization. We use confocal microscopy to directly observe the motion of colloidal particles. This motion is slower in confinement, thus producing glassy behavior in a sample which is a liquid in an unconfined geometry. For higher volume fraction samples (closer to the glass transition), the onset of confinement effects occurs at larger length scales.