Matrix laminates do not have enough parameters to represent the variety of materials that simultaneously conducts several substances, like heat, electricity, diffusive liquids, or electromagnetic composites. For these problems, we must consider a type of microstructures with more structural parameters.

The more general optimal
microstructures are the sequences of ``coated spheres'' called * multicoated
spheres* (Milton).
These structures consist of sequences of concentric spherical layers
that are filled with two materials in alternating order. The properties of these
isotropic structures are controlled by the relative thickness of the
alternating layers.

Structure of "Multicoated matrix laminates"

The construction of ``multicoated matrices'' combines the anisotropy of matrix laminates and the topological complexity of multicoated spheres.

Structure of "Multicoated spheres"

These structures have been described in [#!Milton:1991:PLG!#,#!Cherkaev:1992:ECB!#] These structures exhibit optimal properties in a problem of extremely coupled effective properties, see [#!Cherkaev:1992:ECB!#].