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

Area of Science:

• Polymer Science
• Materials Science
• Computational Chemistry

Background:

• Semicrystalline polymer blends are crucial in materials science.
• Understanding crystallization behavior in these blends is key for property control.
• Phase separation and interfacial effects significantly influence blend performance.

Purpose of the Study:

• To investigate the impact of interface width and compatibilizers on crystallization in binary polymer blends.
• To elucidate the mechanisms hindering crystal growth at and near interfaces.
• To explore the role of block copolymers in modifying interfacial properties and crystallization.

Main Methods:

• Coarse-grained molecular dynamics simulations were employed.
• Monomer size mismatches were introduced to mimic realistic polymer blends and prevent artificial cocrystallization.
• Intermolecular interactions were tuned to control incompatibility and interface width.

Main Results:

• Broad interfaces significantly suppress polymer crystallization and crystal stem growth.
• Incompatible species at the interface, rather than entanglement, are the primary cause of crystallization hindrance.
• The negative impact on crystallization extends beyond the immediate interfacial region.
• Block copolymer addition further reduces interfacial crystallinity, even impeding entangled loop bridge formation.

Conclusions:

• Interface characteristics critically influence crystallization in semicrystalline polymer blends.
• The presence of incompatible polymer segments is a dominant factor in suppressing crystallization.
• Block copolymers, while offering potential for mechanical reinforcement via tie chains, can negatively affect crystallization and entangled structures near interfaces.