Emergence of Connected Binary Spherical Structures from the Self-assembly of an AB<sub>2</sub>C Four-Arm Star Terpolymer
Luyang Li, Zhanwen Xu, Weihua Li
Abstract
We have investigated the self-assembly of the AB2C terpolymer using self-consistent field theory, focusing on the formation of novel “connected” binary spherical phases. Our results reveal that the AB2C four-arm star terpolymer exhibits significantly different phase behaviors from those of the conventional ABC star terpolymer. Specifically, some polygon-tiling patterns, which are the usual stable phases of the ABC star, do not appear in the phase diagram of the AB2C four-arm star, while the ZnS and NaCl binary spherical phases exhibit large stable regions instead. The volume fractions of the binary spherical domains reach so high that they are severely deformed from being spherical. Interestingly, the binary spheres in ZnS and NaCl structures are in close contact due to the star architecture and thus constitute single diamond and single plumber’s nightmare networks, respectively. Our further calculations indicate that the ZnS structure with a largely tunable volume fraction can be used to generate the template of three-dimensional photonic crystals that have large-sized band gaps. Our work not only deepens the understanding of ABC multi-arm star copolymers but may also promote relevant experimental studies.