Multipole expansion of the electric field potential in a soft electromagnetic composite

Abstract

'Soft materials' refer to a class of electromagnetic composites consisting of shaped dielectric particles dispersed in a dielectric fluid subjected to an external applied field. It is known that for spherical suspensions, application of an external electric field of sufficient magnitude will produce chain-like agglomerations of particles in the complex fluid parallel to the applied field. This macroscopic characteristic of anisotropic particle-chain formation is a consequence of mutual dielectrophoresis of the particles via particle polarization. When there exists a dielectric mismatch between the particles and the suspension fluid, distortion of the field in the vicinity of the particle results. Interparticle interactions may also contribute to the local field anisotropicity. Existing studies have been directed at the theoretical description of such interparticle interactions pertinent to fluids containing spherical particles, however research on complex fluids having the inclusion of nonspherical particles are rather sparse. The authors consider the theoretical aspects of complex fluids or soft materials containing a suspension of non-spherical particles in order to evaluate the local electric field distributions and interparticle interaction forces when the fluid is subjected to an external electric field.