Synthesis, characterization, and stimuli‐sensitive properties of triblock copolymer poly(ethylene oxide)‐b‐poly(2‐(diethylamino)ethyl methacrylate)‐b‐poly(N‐isopropylacrylamide)

Abstract

AbstractWell‐defined triblock copolymer poly(ethylene oxide)‐b‐poly(2‐(diethylamino)ethyl methacrylate)‐b‐poly(N‐isopropyl‐acrylamide) (PEO‐b‐PDMAEMA‐b‐PNIPAAm) was synthesized via sequential reversible addition‐fragmentation chain transfer polymerization (RAFT) of 2‐(dimethylamino)ethyl methacrylate (DMAEMA) and N‐isopropylacrylamide (NIPAAm) using α‐methoxy‐ω‐S‐1‐dodecyl‐S‐α‐(α,α′‐dimethyl‐α″‐acetate) poly(ethylene oxide) (mPEO‐DDAT) as macro‐RAFT agent, AIBN as initiator in dioxane at 80°C. The polymerization data indicated that the both RAFT processes were well controlled. The molecular weights of macro‐RAFT agents showed the influence on the RAFT polymerization process. The final PEO‐b‐PDMAEMA‐b‐PNIPAAm triblock copolymer can form uniform micelles in aqueous media above the lower critical solution temperature (LCST) due to containing temperature‐sensitive PNIPAAm block. The micelle size and Dh were dependent on the composition of triblock copolymer and the pH value of the solution. The PEO‐b‐PDMAEMA‐b‐PNIPAAm triblock copolymer showed dual temperature‐ and pH‐sensitive property in aqueous media. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008