Morphology control of polymer blends by a chemical pinning of spinodal decomposition

The ordering dynamics of polymer blends were investigated at the early-to-late stage of spinodal decomposition. The blends studied were 50/50 wt/wt mixtures of polyisoprene and styrene-butadiene random copolymer containing 15 wt% styrene which undergo a very slow ordering process via spinodal decomposition. We succeeded in chemical pinning of a slowly growing phase-separated domain-structure by crosslinking the polymers with a peroxide at various stages of spinodal decomposition. The chemical pinning locks-in the phase-separating domain structures of a certain spatial scale and amplitude of the concentration fluctuations.