Geometrically driven aggregation of unsymmetrical dielectric particles.

Understanding electrostatic interactions among dielectric bodies in the atmosphere and aerosols is central to controlling their aggregation. Polarization effects, which are frequently ignored, are crucial to determine interactions when geometrical anisotropies are present due to surface-induced charge segregation. Here, we adopt a direct integral formulation that accounts for the problem of charged dielectric bodies immersed in a continuum media to explore particle aggregation via geometrical tuning. We show that by breaking the structural symmetry and modifying the close-contact surface between particles of equal charge, it is possible to obtain attractive regimes at short and long distances. We evaluate the electrostatic forces and energy of a set of dimers and trimers composed of spheres, oblates, and prolates in a vacuum, where no counter-ions are present, to construct a phase diagram with the conditions required to form stable aggregates as a function of the geometrical anisotropy. We found that it is possible to direct the aggregation (or dispersion) of two and three positive dielectric particles by adjusting their geometry and controlling the contact surface among them. Our results give insight into a way to control the aggregation of dielectric systems and offer a prospect for directing the assembly of complex particle structures.