Dynamical Correlation Length Scales and Dynamical Heterogeneity in Colloidal-Hard-Sphere Systems Approaching the Glass Transition

When: Wednesday, April 03, 2013 at 12:00 pm
Where: EG 306
Speaker: Mackenzie Bennett
Organization: Northeastern University
Sponsor: SPS

In this experiment, micron-sized polystyrene spheres are dispersed in an aqueous KCl solution. The movements of the particles are measured using an electrical current passing through a micro-pore separating two reservoirs of an acrylic cell containing the colloidal suspension. The motion of the particles produces a noisy current. These noise fluctuations are then analyzed in order to determine the size of cooperative clusters through spatial correlation lengths (dependent on volume fraction). Of particular interest is how the cluster size changes as the colloidal glass transition is approached, a behavior that can be used to test competing theoretical models.