One-Pot Synthesis of ABC Miktoarm Star Terpolymers by Coupling ATRP, ROP, and Click Chemistry Techniques

We report on the one-pot synthesis of well-defined ABC miktoarm star terpolymers consisting of poly(2-(dimethylamino)ethyl methacrylate), poly(epsilon-caprolactone), and polystyrene or poly(ethylene oxide) arms, PS(-b-PCL)-b-PDMA and PEO (-b-PCL)-b-PDMA, taking advantage of the compatibility and mutual tolerability of reaction conditions (catalysts and monomers) employed for atom transfer radical polymerization (ATRP), ring-opening polymerization (ROP), and click reactions. At first, a novel trifunctional core molecule bearing alkynyl, hydroxyl group, and bromine moieties, alkynyl(-OH)-Br, was synthesized via the esterification reaction of 5-ethyl-5-hydroxymethyl-2,2-dimethyl-1,3-dioxane with 4-oxo-4-(prop-2-ynyloxy)butanoic acid, followed by deprotection and monoesterification of alkynyl(-OH)(2) with 2-bromoisobutyryl bromide. In the presence of trifunctional core molecule, alkynyl(-OH)-Br, and CuBr/PMDETA/Sn(Oct)(2) catalytic mixtures, target ABC miktoarm star terpolymers, PS(-b-PCL)-b-PDMA and]PEO(-b-]PCL)-b-PDMA, were successfully synthesized in a one-pot manner by simultaneously conducting the ATRP of 2-(dimethylamino)ethyl methacrylate (DMA), ROP of E-caprolactone (epsilon-CL), and the click reaction with azido-terminated PS (PS-N-3) or azido-terminated PEO (PEO-N-3). Considering the excellent tolerability of ATRP to a variety of monomers and the fast expansion of click chemistry in the design and synthesis of polymeric and biorelated materials, it is quite anticipated that the one-pot concept can be applied to the preparation of well-defined polymeric materials with more complex chain architectures. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3066-3077, 2009