  The viscous coarsening of a phase separated mixture is studied and the
effects of the viscosity contrast between the phases are investigated. From an
analysis of the microstructure, it appears that for moderate departure from the
perfectly symmetric regime the self-similar bicontinuous regime is robust.
However, the connectivity of one phase decreases when its volume fraction
decreases or when it is becoming less viscous than the complementary phase.
Eventually self-similarity breakdown is observed and characterized.
