Particle dynamics in colloidal suspensions above and below the glass-liquid re-entrance transition

¹  Department of Physics, Saint Joseph's University - Philadelphia, PA 19131, USA
²  Department of Physics, Hong Kong University of Science and Technology - Hong Kong
³  Department of Physics and Astronomy, University of Pennsylvania - Philadelphia, PA 19104, USA
⁴  The School of Physics and Astronomy, The University of Edinburgh - Edinburgh, Scotland EH9 3JZ, UK, EU

Corresponding author: phabdas@sju.edu

Received: 12 February 2009
Accepted: 6 May 2009

Abstract

We study colloidal particle dynamics of a model glass system using confocal and fluorescence microscopy as the sample evolves from a hard-sphere glass to a liquid with attractive interparticle interactions. The transition from hard-sphere glass to attractive liquid is induced by short-range depletion forces. The development of liquid-like structure is indicated by particle dynamics. We identify particles which exhibit substantial motional events and characterize the transition using the properties of these motional events. As samples enter the attractive liquid region, particle speed during these motional events increases by about one order of magnitude, and the particles move more cooperatively. Interestingly, colloidal particles in the attractive liquid phase do not exhibit significantly larger displacements than particles in the hard-sphere glass.