Heterograft brush copolymers via romp and triple click reaction strategies involving CuAAC, diels-alder, and nitroxide radical coupling reactions

In this study, an equimolar mixture of oxanorbornenyl-anthracene (ONB-anthracene), oxanorbornenyl-bromide (ONB-Br), and oxanorbornenyl tosylate (ONB-OTs) was polymerized via ring opening metathesis polymerization using the first generation Grubbs' catalyst in CH₂Cl₂ at room temperature to form poly(ONB-anthracene-co-ONB-Br-co-ONB-OTs)₁₀ copolymer as a main backbone. Next, this main backbone was sequentially clicked with a furan protected maleimide-terminated poly(methyl methacrylate), 2,2,6,6-tetramethyl-1-piperidinyloxy-terminated poly(ethylene glycol), and alkyne-terminated poly(ε-caprolactone) (PCL₂₀-alkyne) via Diels-Alder, nitroxide radical coupling, and copper-catalyzed azide-alkyne cycloaddition, respectively, to yield a poly(ONB-g-PMMA-co-ONB-g-PEG-co-ONB-g- PCL)₁₀ heterograft brush copolymer