RAFT polymerization of N-isopropylacrylamide and acrylic acid under γ-irradiation in aqueous media

Pierre Eric Millard, Leonie Barner, Martina H. Stenzel, Thomas P. Davis, Christopher Barner-Kowollik, Axel H.E. Müller

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The ambient temperature (20°C) reversible addition fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AA) conducted directly in aqueous media under γinitiation (at dose rates of 30 Gy·h-1) proceeds in a controlled fashion (typically, M̄w/M̄n < 1.2) to near quantitative conversions and up to number-average molecular weights of 2.5 × 105 g·mol-1 for PNIPAAm and 1.1 × 105 g·mo-1 for PAA via two water-soluble trithiocarbonate chain transfer agents, i.e., S,S-bis(α,α′- dimethyl-α″-acetic acid)trithiocarbonate (TRITT) and 3-benzylsulfanyltbiocar-bonylsulfanyl propionic acid (BPATT). The generated polymers are successfully chain extended, which suggests that the RAFT agents are stable throughout the polymerization process so that complex and well-defined architectures can be obtained.

Original languageEnglish
Pages (from-to)821-828
Number of pages8
JournalMacromolecular Rapid Communications
Issue number11
Publication statusPublished - 2 Jun 2006
Externally publishedYes


  • γ-radiation
  • Acrylic acid
  • Kinetics (polym.)
  • N-isopropylacrylamide
  • Reversible addition fragmentation chain transfer (RAFT)
  • Smart polymers

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