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

Abstract

Abstract Well‐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 D h 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