If you can express the surface (aka, boundary) between your materials as one or more parametric surfaces, you should be able to insert that surface (aka, boundary) into the geometry. Once those surfaces are there, you should be able specify material properties of the resulting domains in the usual way.
From the Comsol Reference Guide:
A parametric surface is a surface in 3D where you use two parameters to define the
coordinates of the surface... To create a parametric surface, right-click a 3D geometry and
select More Primitives>Parametric Surface( ). Then enter the properties of the parametric surface.."
From the Comsol Reference Guide:
A parametric surface is a surface in 3D where you use two parameters to define the
coordinates of the surface... To create a parametric surface, right-click a 3D geometry and
select More Primitives>Parametric Surface( ). Then enter the properties of the parametric surface.."
