Encapsulation and release by star-shaped block copolymers as unimolecular nanocontainers

Authors

  • Dilek Kul,

    1. Department of Chemistry, Karadeniz Technical University, 61080 Trabzon, Turkey
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  • Lieven M. Van Renterghem,

    1. Department of Organic Chemistry, Polymer Chemistry Research Group, Ghent University, Krijgslaan 281 S4-bis, B-9000 Ghent, Belgium
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  • Michael A.R. Meier,

    1. Laboratory of Macromolecular Chemistry and Nanoscience, Eindhoven University of Technology and Dutch Polymer Institute, PO Box 513, 5600 MB Eindhoven, The Netherlands
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  • Satu Strandman,

    1. Laboratory of Polymer Chemistry, University of Helsinki, P.O. Box 55, FIN-00014, Finland
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  • Heikki Tenhu,

    1. Laboratory of Polymer Chemistry, University of Helsinki, P.O. Box 55, FIN-00014, Finland
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  • Sevil S. YIlmaz,

    1. Department of Chemistry, Karadeniz Technical University, 61080 Trabzon, Turkey
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  • Ulrich S. Schubert,

    1. Laboratory of Macromolecular Chemistry and Nanoscience, Eindhoven University of Technology and Dutch Polymer Institute, PO Box 513, 5600 MB Eindhoven, The Netherlands
    2. Laboratory of Organic and Macromolecular Chemistry, Friedrich-Schiller University Jena, Humboldtstr. 10, 07743 Jena, Germany
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  • Filip E. Du Prez

    Corresponding author
    1. Department of Organic Chemistry, Polymer Chemistry Research Group, Ghent University, Krijgslaan 281 S4-bis, B-9000 Ghent, Belgium
    • Department of Organic Chemistry, Polymer Chemistry Research Group, Ghent University, Krijgslaan 281 S4-bis, B-9000 Ghent, Belgium
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Abstract

A five-arm star-shaped poly(ethylene oxide) (PEO) with terminal bromide groups was used as a macroinitiator for the atom transfer radical polymerization of tert-butyl acrylate (tBA), resulting in five-arm star-shaped poly(ethylene oxide)-block-poly(tert-butyl acrylate) block copolymers. The polymerization proceeded in a controlled way using a copper(I)bromide/pentamethyl diethylenetriamine catalytic system in acetonitrile as solvent. The hydrolysis of the tBA blocks of the amphiphilic star-shaped PEO-b-PtBA block copolymer resulted in dihydrophilic star structures. The encapsulation of the star-block copolymers and their release properties in acid environment have been followed by UV-spectroscopy and color changes, using the dye methyl orange as a hydrophilic guest molecule. Characterization of the structures has been done by 1H NMR, size exclusion chromatography, MALDI-TOF, and differential scanning calorimetry. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 650–660, 2008

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