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

KUL D., Van Renterghem L. M., Meier M. A. R., Strandman S., Tenhu H., YILMAZ Ş., ...More

JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, vol.46, no.2, pp.650-660, 2008 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 46 Issue: 2
  • Publication Date: 2008
  • Doi Number: 10.1002/pola.22413
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.650-660
  • Keywords: amphiphiles, atom transfer radical polymerization (ATRP), host-guest systems, nanocontainer, star-block copolymer, TRANSFER RADICAL POLYMERIZATION, FRAGMENTATION CHAIN TRANSFER, HOST-GUEST CHEMISTRY, POLY(ACRYLIC ACID), POLY(ETHYLENE OXIDE), RAFT PROCESS, POLYMERS, WATER, CORE, DENDRIMERS
  • Karadeniz Technical University Affiliated: Yes


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 H-1 NMR, size exclusion chromatography, MALDI-TOF, and differential scanning calorimetry. (C) 2007 Wiley Periodicals, Inc.