Effect of interfacial transport on the diffusivity of highly filled polymers

The diffusivity of substances, such as moisture, through polymer composites is often described by an effective macroscopic quantity, even though microscopically the might be far from uniform. In this work, we study theoretical example a permeable matrix containing equal-sized impermeable spheres. We assume that, due to interface effects, in vicinity spheres higher than its bulk diffusivity. Using numerical simulations composite's diffusivity, show that upon formation large clusters highly interfaces, i.e. near percolation spheres, composite rises sharply. For values volume fraction up close-packing limit, decreases increased tortuosity. This effect well analytical solution for