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) (PtBA) side chains: poly(ONB-g-PMMA)-b-poly(ONB-g-PCL) and poly(ONB-g-PtBA)-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 PtBA-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.