Particle tracking and analysis of depletion induced self assembly of colloidal rods

Abstract

To get a good understanding of the depletion interaction acting on hard rods we present the tracking and analysing on the single particle level of the self assembly of silica rods made attractive using a depletant. Silica rods and spheres were successfully synthesised. Sediments with different volume fraction of these particles were made and imaged. Using a rod tracking code the locations and orientations of the rods were determined. By analysing this data we obtained the amount of order achieved within different samples. We saw that optima in depletion % (v/v) and pressure can be found. Also the amount of depletant needed depends on the size ratio rods:depletant. The dynamics of the system have also been studied showing the timescale on which the depletant interaction acts, after five minutes clustered particles were visible.