Fracture phase separation.
Here we report novel phase-separation behavior accompanying mechanical fracture ("fracture phase separation"), which is observed in polymer solutions. Surprisingly, mechanical fracture becomes a dominant coarsening process of the phase separation. The transition from viscoelastic to fracture phase separation corresponds to the "ductile-to-brittle transition" in fracture of materials under shear deformation. The only difference between fracture phase separation and material fracture is whether the deformation is induced internally by phase separation itself or externally by loading. This suggests a general physical scenario of mechanical selection of the kinetic pathway of inhomogeneization of materials under stress.