Slow dynamics in cylindrically confined colloidal suspensions

TL;DR

This study investigates how confinement within cylindrical microcapillaries affects the dynamics of colloidal suspensions, revealing that particles slow down near walls and in narrower tubes, indicating interfacial effects influence glassy behavior.

Contribution

It provides experimental evidence that confinement geometry and wall proximity significantly alter particle dynamics in colloidal suspensions, highlighting interfacial effects on glass transition behavior.

Findings

Particles move slower in narrower tubes.

Mobility decreases near the tube walls.

Confinement induces a gradient in particle mobility.

Abstract

We study bidisperse colloidal suspensions confined within glass microcapillary tubes to model the glass transition in confined cylindrical geometries. We use high speed three-dimensional confocal microscopy to observe particle motions for a wide range of volume fractions and tube radii. Holding volume fraction constant, we find that particles move slower in thinner tubes. The tube walls induce a gradient in particle mobility: particles move substantially slower near the walls. This suggests that the confinement-induced glassiness may be due to an interfacial effect.