Anisotropic self-assembly of soft particles mediated by elliptically polarized AC fields

Abstract

Attractive dipole interactions can be induced between equally charged soft nanoparticles under the influence of AC electric fields. The combination of charge repulsion and dipole attraction, along with different screening responses from an underlying electrolyte, lead to complex aggregations ranging from chain-like formation for linear polarizations to isotropic planar structures in the case of circular polarizations. In this work, we analyze the role of varying field anisotropies in these self-assembled structures. To this end, the formalism previously developed for the coarse-grained interactions of soft particles in the presence of linear [T.~Colla {\it et al.}, ACS Nano {\bf 12}, 4321-4337 (2018)] and circular [M.~Reich {\it et al.}, Soft Matter {\bf 21}, 1516-1528 (2025)] field polarizations is naturally extended to incorporate elliptical polarizations of arbitrary asymmetries. A rich variety of self-assembly formations is found at intermediate field anisotropies, thus bridging the gap between linear and circular field-induced self-assembly scenarios.