Slow dynamics of dense colloidal suspensions in two and three dimensions

Abstract

We develop computer codes to efficiently & accurately locate and track particles in 2D & 3D images obtained from confocal microscopy. We prepare 2D & 3D colloidal systems with area/volume fractions (phi) close to the glass transition and compare their properties, behaviour and dynamics in this regime. These dynamics are characterised by structural quantities such as mean square displacement, pair correlation function, bond orientational order & intermediate scattering function. We show that our 3D systems have strong icosahedral order with very weak tendencies towards HCP and FCC orders, and that these structures do not change with phi. We quantify characteristic spatial and bond angle relaxation times, in order to compare their behaviours as we approach glass transition in 2D & 3D. Similarly, we describe how to quantify a dynamic correlation length for our systems.