Coarsening of bicontinuous structures via nonconserved and conserved dynamics.

Coarsening subsequent to phase separations occurs in many two-phase mixtures. While unique scaled particle size distributions have been determined for highly asymmetric mixtures in which spherical particles form in a matrix, it is not known if a unique scaled structure exists for symmetric mixtures, which yield bicontinuous structures having intricately interpenetrating phase domains. Using large-scale simulations, we have established that unique scaled microstructures exist in symmetric mixtures evolving via nonconserved and conserved dynamics. We characterize their morphologies by the interfacial shape distribution, a counterpart to the particle size distribution, and their topologies by the genus. We find that the two dynamics result in unique, but different, scaled interfacial shape distributions, with conserved dynamics yielding a narrower distribution around zero mean curvature. In contrast, the two scaled structures are topologically similar, having nearly equal values of the scaled genus.