Sedimentation and diffusion in an experimental hard-sphere-plus-dipolar colloidal system

Abstract

Laser scanning confocal microscopy was used to image a thin sediment of a Brownian colloidal suspension of PMMA spheres in a decalin/TCE solvent. The sediment is imaged in its entirety in 3-dimensions, as well as with 2-dimensional time-series captured incrementally throughout the sediment. The structure and dynamics are analysed and compared to a hard-sphere system. AC electric fields are applied parallel to gravity to attempt to induce a dipolar interaction in the colloidal spheres. If the system is confirmed to be hard-sphere like, then this allows comparison of the system with applied fields to a hard-sphere-plus-dipolar system.