(474d) Aggregation in a Suspension of Self-Propelled Magnetic Colloidal Particles Studied Via Brownian Dynamics Simulations

Ferrocolloids interacting via dipole-dipole interactions subject to an external magnetic field form aggregates of various sizes at different time scales. Inserting self-propulsion ability to these particles promises significant benefits in the development of novel materials. It is well understood that by enhancing diffusion, in this case by self-propulsion, the time scale for particle interactions is reduced to an extent of forming aggregates much faster.  It is unclear, however, the effect of self-propulsion of these particles, particularly at very high propulsion speeds, to cluster size formation in relation to the applied magnetic field and interparticle interactions. In this work, we propose a simple colloidal model consisting of a monodisperse suspension of self-propelled magnetic particles immersed in a Newtonian fluid subject to a constant external magnetic field. Using Brownian dynamics simulation, we interrogate the suspension over time by measuring cluster properties, such as mean squared radius of gyration, mean cluster mass, number of clusters and cluster diffusivities. All these properties are then compared for various particle speeds, magnetic field strengths, and dipolar coupling constants.