Block‐brush copolymers via ROMP and sequential double click reaction strategy

We report an efficient way, sequential double click reactions, for the preparation of brush copolymers with AB block‐brush architectures containing polyoxanorbornene (poly (ONB)) backbone and poly(ε‐caprolactone) (PCL), poly(methyl methacrylate) (PMMA) or poly( tert ‐butyl acrylate) (P t BA) side chains: poly(ONB‐ g ‐PMMA)‐ b ‐poly(ONB‐ g ‐PCL) and poly(ONB‐ g ‐P t BA)‐ b ‐poly(ONB‐ g ‐PCL). The living ROMP of ONB affords the synthesis of well‐defined poly(ONB‐anthracene) 20 ‐ b ‐poly (ONB‐azide) 5 block copolymer with anthryl and azide pendant groups. Subsequently, well‐defined linear alkyne end‐functionalized PCL (PCL‐alkyne), maleimide end‐functionalized PMMA (PMMA‐MI) and P t BA‐MI were introduced onto the block copolymer via sequential azide‐alkyne and Diels‐Alder click reactions, thus yielding block‐brush copolymers. The molecular weight of block‐brush copolymers was measured via triple detection GPC (TD‐GPC) introducing the experimentally calculated dn / dc values to the software.