H-shaped (ABCDE type) quintopolymer via click reaction [3 + 2] strategy

H-shaped quintopolymer containing different five blocks: poly(e-caprolactone) (PCL), polystyrene (PS), poly(ethylene glycol) (PEG), and poly(methyl methacrylate) (PMMA) as side chains and poly(tert-butyl acrylate) (PtBA) as a main chain was simply prepared from a click reaction between azide end-functionalized PCL-PS-PtBA 3-miktoarm star terpolymer and PEG-PMMA-block copolymer with alkyne at the junction point, using Cu(I)/N,N,N′,N″, N″-pentamethyldiethylenetriamine (PMDETA) as a catalyst in DMF at room temperature for 20 h. The H-shaped quintopolymer was obtained with a number-average molecular weight (M_n) around 32,000 and low polydispersity index (M_w/M_n) 1.20 as determined by GPC analysis in THF using PS standards. The click reaction efficiency was calculated to have 60% from ¹H NMR spectroscopy.