One-Shot Synthesis and Melt Self-Assembly of Bottlebrush Copolymers with a Gradient Compositional Profile.

Morphological control plays a central role in soft materials design. Herein, we report the synthesis of a gradient bottlebrush architecture and its role in directing molecular packing in the solid state. Bottlebrush copolymers with gradient interfaces were prepared via one-shot ring-opening metathesis polymerization of exo- and endo-norbornene-capped macromonomers. Kinetic studies revealed a gradient compositional profile separating the two blocks along the backbone. Side-chain symmetric gradient bottlebrush copolymers exhibited a strong tendency to assemble into cylindrical microstructures, in contrast to their block copolymer analogs with sharp interfaces. Such exquisite architectural control of the interfacial composition affords a delicate handle to direct macromolecular assembly.