AC electrokinetics of the microparticles in electrorheological solids

Under the application of electric fields, the structure of electrorheological (ER) solids can be changed from the body-centered tetragonal lattice (ground state) to other lattices. For a particle in the lattice, we derive its dipole factor by taking into account both the local-field effect arising from all the other particles and the multipolar interaction between two touching particles, through the Ewald–Kornfeld formulation and multiple image method. For simplifying the study, the dipole factors are expressed in the dielectric dispersion spectral representation exactly. It is found that the electrorotation (EOR) spectrum of ER solids can be affected significantly by the structure transformation, and the local-field effect as well as the multipolar interaction. Our results are well understood in the spectral representation theory. Thus, it is possible to monitor the structure of ER solids by detecting the EOR spectrum.  2004 Elsevier B.V. All rights reserved. PACS: 77.22.Ej; 82.70.-y; 83.80.Gv