Electrohydrodynamic Structuring of Colloidal Particles on Leaky Dielectric Drops

Abstract

This Master's thesis shows experimentally how colloidal particles in leakydielectric liquid drops are actively structured by applying a DC electric eld.Colloidal particles in small droplets with a diameter of 100 m show similarstructuring to what has previously been observed on bigger drops (1 mm),showing ribbon formation, spinning domains and pupil eects. It is shownhow electrohydrodynamic assembly of colloidal particles on a drop surfacedepends on the electric eld strength, and how this enables fast assembly ofthe particles. The particles used in the experiments are clay particles, layereddouble hydroxides and insulating beads. The layered double hydroxides showsimilar structuring to the clay particles. The results suggest that active con-trol of colloidal particles on leaky-dielectric drops by an electric eld can leadto new ways of producing Janus shells and other 'smart armoured' droplets.