COMPARISON BETWEEN THE TORQUATO-RINTOUL BOUNDS FOR THE INTERFACE EFFECT IN COMPOSITE MEDIA AND ELEMENTARY RESULTS

We show that the interface effect on the properties of composite media recently proposed by Torquato and Rintoul equally follows from taking the limit in the dipolar polarizability of a coated sphere: the criti cal values are simply those that make the dipolar polarizability vanis h. We also show that the Torquato-Rintoul bounds are either close to t he Clausius-Mossotti relation or provide poor estimates. Finally, we n otice that their bounds do not agree particularly well with experiment al data.