Assembly and dynamics of propelling ferromagnetic colloids

Abstract

Active colloids is a growing field of research that studies the emergent phenomena exhibited in systems of self-propelling particles as a result of the interactions between them that could not be observed if these components were isolated. These phenomena can be observed in a wide variety of systems. In this work, I show how a collection of oscillating colloidal rotors, or simply, shakers, immersed in a viscoelastic fluid, specifically, a solution of polyacrylamide (PAAM), can display this behaviour, forming complex zig-zag dynamic bands that grow linearly in time. I have investigated the dynamics of this band growth for two different PAAM concentrations, as well as the hydrodynamic flow around these shakers for both cases. This helps understanding the complex dynamics of these fluids, having implications in soft matter physics and microfluidics and in biophysics