Synthesis of bundle copolymers as an emergent class of copolymer architecture

Copolymers play a central role in soft materials owing to their capacity for diverse molecular designs. While numerous combinations of composition and topology have been explored for the development of copolymers, only four types of basic architecture (random, sequence-controlled, block, and graft) have been synthetically and historically achievable. Herein, we introduce a new class of copolymers— bundle copolymers —comprising multiple different chains interlinked and aligned in a parallel configuration. To exemplify this concept, bundle copolymers are synthesised via nanoconfined polymerisation, in which radical polymerisation of vinyl monomers occurs alongside vinyl-functionalised polydimethylsiloxane within the one-dimensional channels of a metal–organic framework. Unlike conventional copolymers, bundle copolymers feature aligned lateral strands whose proximity can be modulated by the density of covalent junctions. This innovative approach for tying multiple chains opens a new avenue for copolymer design, expanding the landscape of polymer chemistry.