Light-induced RAFT single unit monomer insertion in aqueous solution—toward sequence-controlled polymers

Annelore Aerts, Reece W. Lewis, Yanyan Zhou, Nino Malic, Graeme Moad, Almar Postma

Research output: Contribution to journalArticleAcademicpeer-review

14 Citations (Scopus)

Abstract

First report on the sequential, visible light-initiated, single unit monomer insertion (SUMI) of N,N-dimethylacrylamide (DMAm) into the reversible addition fragmentation chain transfer (RAFT) agent, 4-((((2-carboxyethyl)thio)carbonothioyl)thio)-4-cyanopentanoic acid (CTA1), in aqueous solution is provided. The specificity for SUMI over formation of higher oligomers and/or RAFT agent-derived by-products is higher for longer irradiation wavelengths. Red light provides the cleanest product (selective SUMI), showing a linear pseudo-first order kinetic profile to high (>80%) conversion, but also the slowest reaction rate. Blue light provides a relatively rapid reaction, but also gives some by-products (<2%) and the kinetic profile displays a conversion plateau at >65% conversion. Higher specificity with red light is attributed to CTA1 absorbing at longer wavelengths than the SUMI product, which allows selective excitation of CTA1. The use of a higher reaction temperature (65 °C vs ambient) results in a higher reaction rate and a reduction in oligomer formation.

Original languageEnglish
Article number1800240
Number of pages7
JournalMacromolecular Rapid Communications
Volume39
Issue number19
DOIs
Publication statusPublished - 1 Oct 2018

Keywords

  • radical polymerization
  • RAFT
  • sequence defined polymers
  • single unit monomer insertion
  • Pentanoic Acids/chemistry
  • Light
  • Polymerization
  • Kinetics
  • Acrylamides/chemistry
  • Photochemical Processes

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