Mapping formation pathways and end group patterns of stimuli-responsive polymer systems via high-resolution electrospray ionization mass spectrometry

Gene Hart-Smith, Tara M. Lovestead, Thomas P. Davis, Martina H. Stenzel, Christopher Barner-Kowollik

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

"Smart" polymers and polymer - protein conjugates find a vast array of biomedical applications. Ambient temperature reversible addition fragmentation chain transfer (RAFT) polymerizations conducted in an aqueous environment are a favorable method of choice for the synthesis of these materials; however, information regarding the initiation mechanisms behind these polymerizations - and thus the critical polymer end groups - is lacking. In the current study, high-resolution soft ionization mass spectrometry techniques were used to map the product species generated during ambient temperature γ-radiation induced RAFT polymerizations of N-isopropylacrylamide NIPAAm and acrylic acid (AA) in aqueous media, allowing the generated end groups to be unambiguously established. It was found that trithiocarbonate and •R radicals produced from the radiolysis of the RAFT agent, •OH and •OOH radicals produced from the radiolysis of water, and •H radicals produced from the radiolysis of water, RAFT agent, or monomer were capable of initiating polymerizations and thus contribute toward the generated chain ends. Additionally, thiol terminated chains were formed via degradation of trithiocarbonate end groups. The current study is the first to provide comprehensive mapping of the formation pathways and end group patterns of stimuli-responsive polymers, thus allowing the design and implementation of these materials to proceed in a more tailored fashion.

Original languageEnglish
Pages (from-to)2404-2415
Number of pages12
JournalBiomacromolecules
Volume8
Issue number8
DOIs
Publication statusPublished - 13 Aug 2007
Externally publishedYes

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