One-Pot Synthesis of PS-b-PEO-b-PtBA Triblock Copolymers via Combination of SET-LRP and Click Chemistry Using Copper(0)/PMDETA as Catalyst System

Triblock copolymers of polystyrene-block-poly(ethylene oxide)-block-poly(tert-butyl acrylate) (PS-b-PEO-b-PtBA) were prepared via combination of single electron transfer living radical polymerization (SET-LRP) with click chemistry using Cu(0)/N,N,N',N '',N ''-pentamethyldiethylenetriamine (PMDETA) as catalyst system. The alpha,omega-heterofunctionalized PEO with an ethoxyethyl-protected hydroxyl group and an active hydroxyl group was synthesized via anionic ring-opening polymerization (ROP) of ethylene oxide (EO) using potassium 2-( I-ethoxyethoxy)ethoxide as initiator. After further modifications of the end groups, the PEO with alkyne and bromine groups was obtained. Meanwhile, bromine-terminated polystyrene (PS-Br) was synthesized by atom transfer radical polymerization (ATRP), then the bromine end groups were transformed to azide groups by nucleophilic substitution reaction in N, N-dimethylformamide (DMF) in the presence of excessive sodium azide. Lastly, in the presence of Cu(0)/PMDETA, bromine end group of PEO initiated the polymerization of tert-butyl acrylate (tBA) by SET-LRP, the formed Cu(I) in situ was used directly to catalyze the click coupling between azide group of PS and alkyne group of PEO. Thus, the triblock copolymers PS-b-PEO-b-PtBA could be prepared by one-pot strategy. The obtained triblock copolymers and intermediates were characterized by SEC, H-1 NMR, and FT-IR in detail.