Photo-Sensitive RAFT-Agents for Advanced Microparticle Design

Kaupp, Michael, Tischer, Thomas, Hirschbiel, Astrid F., Vogt, Andrew P., Geckle, Udo, Trouillet, Vanessa, Hofe, Thorsten, Stenzel, Martina H., & Barner-Kowollik, Christopher (2013) Photo-Sensitive RAFT-Agents for Advanced Microparticle Design. MACROMOLECULES, 46(17), pp. 6858-6872.

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Abstract

The current contribution describes the combination of an efficient reversible deactivation radical polymerization process (reversible addition–fragmentation chain transfer (RAFT) polymerization) with a mild light-induced modular ligation technique. A novel RAFT-agent was synthesized which carries a photoactive group based on ortho-quinodimethane (photo-enol) chemistry. The novel photoreactive RAFT-agent controls the polymerization of a wide range of monomers such as styrene, N,N-dimethylacrylamide and a protected glycomonomer (2-(2′,3′,4′,6′-tetra-O-acetyl-β-d-mannosyloxy)ethyl acrylate) with dispersities between 1.07 and 1.17 (3500 g·mol–1Mn ≤ 10100 g·mol–1) and quantitative end-group functionalization. The photo-enol group reacts with dieneophiles under mild irradiation (λmax = 320 nm) at ambient conditions – so that the RAFT-group remains intact – and without any catalyst to form block copolymers in a matter of minutes. Furthermore, the RAFT-polymers can be photografted onto porous polymeric (poly(glycidyl methacrylate)) microspheres, after a one-step prefunctionalization with maleimide moieties. The successful photografting is evidenced by scanning electron microscopy (SEM), elemental analysis (EA), X-ray photoelectron spectroscopy (XPS) and high resolution attenuated total reflectance (ATR) FT-IR microscopy, which leads to qualitative as well as quantitative grafting data. The grafting densities obtained for polystyrene are close to 0.11 chains per nm2 (Mn = 3900 g·mol–1) and for poly(N,N-dimethylacrylamide) close to 0.12 chains per nm2 (Mn = 3500 g·mol–1). To highlight the additional benefit of employing a light-induced grafting reaction, Janus microspheres were prepared with poly(N,N-dimethylacrylamide) employing a Pickering emulsion approach and illustrated via ATR-FT-IR microscopy.

Impact and interest:

23 citations in Scopus
25 citations in Web of Science®
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ID Code: 97118
Item Type: Journal Article
Refereed: Yes
DOI: 10.1021/ma401242g
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > Institutes > Institute for Future Environments
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Deposited On: 07 Sep 2016 06:04
Last Modified: 08 Sep 2016 05:02

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