Study on permittivity of composites with core–shell particle

An effective permittivity model of composite with interfacial shell is established. The concentric core–shell ellipsoidal particle randomly mixed with matrix is replaced by solid particle mixed with the same matrix, and the equivalent solid particle has the same radius as the original coating shell. Based on the effective medium theory, the formula for the effective permittivity of two-phase composite with interface is derived, then a simple self-consistent method is applied to modify the formula. With the modified formula, the influence of the structure parameter, the permittivity of the shell, the shape and the volume content of the core on the effective permittivity are investigated. The theoretical results on the effective permittivity of polystyrene–barium titanate composites with interfaces are in agreement with the experimental data.