Synthesis and Characterization of Core‐Shell Bottlebrush Polymers via Controllable Polymerization

Abstract This research was focused on the synthesis of well‐defined bottlebrush polymers (BBPs) comprising of polynorbornene (PNB) backbones and side‐chains of the polylactide (PLA)‐b‐polystyrene (PS). The PNB backbones were synthesized via ring‐opening metathesis polymerization of norbornene, and then L‐lactide (LA) was first grafted to the backbones to form PLA side‐chains by ring‐opening polymerization. Afterwards, styrene was further grafted to the PLA cantilever with triothiocarbonate modification via reversible addition‐fragmentation chain transfer polymerization to form PLA‐b‐PS side‐chains. Controllable polymerization was achieved by introducing each block in stages. A novel structure with PLA and PS block arranged in tandem was constructed, and their morphologies of self‐assembly in bulk were investigated by transmission electron microscopy imaging. The results demonstrated that the compositions and molecular weight of the side‐chains in the BBPs affected the self‐assembling morphologies of the BBPs significantly, and revealed that the polymers were with core‐shell structures.