Effects of Particle Polarizability in Their Two-Body and Many-Body Interactions

Electrostatic interactions play a vital role in governing self-assembly of soft matter systems including colloids and nanoparticles. For metallic and dielectric nanoparticle systems stabilized by salts, particle polarizability complicates the way electrical field propagates, which in turn affects in their effective interaction and assembly behavior. In the present study, we investigate the effects of the particle dielectric constant on their two-body and many-body interactions in the presence of multivalent salts. Using coarse-grained modelling and Molecular Dynamics simulation, we show that uncharged metallic particles are purely repulsive, whereas dielectric particles are attractive at short separations and repulsive beyond a certain separation. Such a difference is shown to stem from the interaction between the polarizable particles and the surrounding salt ions. We also demonstrate how the salt ions confined in a superionic crystal of the particles influence the many-body interaction between the particles depending on salt concentration and valency. Overall, our work show that particle polarizability has important influences on their effective interaction, and hence their assembly behavior.