Encapsulation and Release by Star-Shaped Block Copolymers as Unimolecular Nanocontainers
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Kul, Dilek; van Renterghem, Lieven M.; Meier, Michael; Strandman, Satu; Tenhu, Heikki; Yilmaz, Sevil S.; Schubert, Ulrich S.; Prez, Filip E. Du
- 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)-blockpoly(
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.
- Year:
- 2008
- Type of Publication:
- Article
- Keywords:
- amphiphiles; atom transfer radical polymerization ATRP; host-guest systems; nanocontainer; star-block copolymer
- Journal:
- Journal of Polymer Science: Part A: Polymer Chemistry
- Volume:
- 46
- Pages:
- 650 - 660