Dielectric virial expansion of polarizable dipolar spheres

Predicting the static dielectric permittivity for composites with polarizable components remains a theoretical challenge. The typical Maxwell-Garnett mixing rule or its variant approximates the composite permittivity with a linear average of inclusion's polarizability, which neglects the inter-particle interactions. A systematic density expansion is developed to predict the composite permittivity that includes the contribution from interactions of multiple polarizable particles. The lowest order term in such expansion reduces to the Maxwell-Garnett rule. Including the second order term results in a parameter-free prediction, which matches the independently measured values for a set of seven polymer-nanoparticle composites.