Topology-Controlled Self-Assembly of Unit-Matched AB Block Copolymers

Molecular architecture provides an additional design parameter for block copolymer self-assembly beyond chemical incompatibility and molecular weight. Here, we investigate the self-assembly of unit-matched AB block copolymers with different chain architectures, including diblock, multiblock, comb-like, and star-like topologies. By constructing each system from the same AB building unit, the effect of chain connectivity can be isolated from changes in composition or local interaction strength.

Coarse-grained molecular simulations show that chain architecture strongly influences the ordering tendency of AB block copolymers. Architectures that connect multiple AB units in a topology compatible with the ordered morphology promote microphase separation by reducing the entropic penalty for ordering. Consequently, the order–disorder transition, composition fluctuations, and morphology development become architecture-dependent even at fixed AB interaction. The role of topology is also discussed in confined self-assembly, where packing frustration and interfacial interactions compete with the intrinsic preference for ordered structures.

These results demonstrate that chain architecture can serve as an independent handle for controlling block copolymer self-assembly. The unit-matched comparison provides guidelines for designing low-χ block copolymer systems with enhanced ordering capability, with potential relevance to nanoscale patterning and directed self-assembly.