(523g) Directed Assembly of Binary Structures of Ellipsiods

Directed assembly of colloidal particles has applications in photonic materials, anti-fouling surfaces, and tunable materials. Technological applications require packed structures composed of particles that respond and relax differently to the external field. However, there are limited models available to account for the interactions of binary systems consisting of particles with different shapes and material properties. Our approach implements the ellipsoid-dipole model in a Monte Carlo algorithm to analyze the directed assembly of binary suspension of anisotropic ellipsoids and spheres in a two-dimensional confinement. The binary suspensions are composed of diamagnetic ellipsoids and paramagnetic spheres suspended in a ferrofluid medium. The analysis includes varying the ellipsoid aspect ratio, the number ratio between ellipsoids and spheres, and the relative permeability of the medium. We analyze the main features of the phases due to the competing interactions at different conditions. Simulation results show triangular structures at low permeabilities and low number sphere-to-ellipsoid ratios. The opposite trend is observed at higher permeabilities, with ordered configurations at a high number sphere to ellipsoid ratio. Furthermore, simulation results of systems with similar permeabilities show side-to-side chains of ellipsoids linked together by spheres. The simulation results show the relevance of the competing interactions between the components in binary suspensions to generate tunable structures.