Coarse-Grained Simulations of Crystallization in Phase-Separated Polymer Blends with Block Copolymer Compatibilizers

We employ coarse-grained molecular dynamics simulations to investigate crystallization in binary blends of phase-separated semicrystalline polymers with and without block copolymer compatibilizers. To mimic realistic semicrystalline polymer blends, we introduce mismatches in monomer sizes of different polymers to avoid artificial cocrystallization. By tuning the intermolecular interactions, we adjust the incompatibility and the width of the interfaces between different polymers. We find that broad interfaces significantly hinder crystallization and crystal stem growth, not due to entanglement constraints, but because of the presence of incompatible species near the interface. The suppression of crystallization extends beyond the interfacial region. Adding block copolymer compatibilizers, which impede disentanglement near the interface, further reduces interfacial crystallinity. While long copolymers can form tie bridges across interfaces and offer potential mechanical reinforcement, they also hinder the formation of entangled loop bridges by reducing crystallization near interfaces.