Facile Synthesis of Amphiphilic Bottlebrush Block Copolymers Bearing Pyridine Pendants via Click Reaction from Protected Alkyne Side Groups

We present the facile synthetic platform for the production of amphiphilic bottlebrush block copolymers bearing pyridine pendants through combination of living anionic polymerization (LAP), ring-opening metathesis polymerization (ROMP), and copper-catalyzed azide-alkyne cycloaddition (CuAAC). omega-Norbornenyl poly( 4-(( trimethylsilyl) ethynyl) styrene) (NBPTMSESt) with controlled molecular weights (M-n = 3-4 kDa) and low dispersity (D = 1.03-1.08) was synthesized by LAP and the subsequent end-capping reaction with exo-N-(n-decyl-10-phenylacrylate)-5-norbornene-2,3-dicarboximide. Well-defined bottlebrush block copolymers (M-n = 134-548 kDa, D = 1.04-1.14) were achieved through sequential ROMP of omega-norbornenyl polystyrene with NBPTMSESt and subsequently deprotected with the clickable alkyne group. Amphiphilic bottlebrush block copolymers were obtained by the click reaction of alkyne and azide functional pyridines in the presence of the organic-soluble catalyst/ligand system of CuBr(PPh3)(3) and N,N,N',N '',N ''-pentamethyldiethylenetriamine. These polymers exhibited the three-dimensional ordered porous films through breath-figure self-assembly.