Facile Synthesis and Topological Transformation of Multicomponent Miktoarm Star Copolymers.

Multicomponent miktoarm stars (MMSs) comprising at least three kinds of chemically different arm segments are extremely important due to their great potential as multiphase materials to elucidate composition/topology-dependent properties and applications. At present, a "core first" route gives ABC stars, "coupling onto" and combinatorial methods afford ABC and ABCD stars, and modular and iterative approaches enable facile synthesis of MMSs with five or more components. Meanwhile, the introduction of stimuli-labile linkages and couplable groups into star polymers further enriches the family of smart materials. Upon external stimuli, linking reaction, or postpolymerization modification, miktoarm stars are potentially converted into other architectural polymers such as linear, tadpole-like, graft, and dendrimer-like polymers via cleavage and rearrangement in the chain structure. This feature article aims to systematically summarize the synthetic methods and versatile topological transitions of ABC, ABCD, and ABCDE stars. The advantages and limitations of each approach are highlighted, and the future considerations on developments and challenges are discussed.