Synthesis and characterization of new pH- and thermo-responsive hydrogels based on N-isopropylacrylamide and 2-oxazolines

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Juan Carlos Rueda - , Pontificia Universidad Católica del Perú (Author)
  • Estuardo Campos - , Pontificia Universidad Católica del Perú (Author)
  • Hartmut Komber - , Leibniz Institute of Polymer Research Dresden (Author)
  • Stefan Zschoche - , Leibniz Institute of Polymer Research Dresden (Author)
  • Liane Haeussler - , Leibniz Institute of Polymer Research Dresden (Author)
  • Brigitte Voit - , Leibniz Institute of Polymer Research Dresden (Author)

Abstract

New pH- and thermo-responsive hydrogels (HG) were synthesized by free radical polymerization of N-isopropylacrylamide and a macromonomer, which was a hydrolyzed random copolymer of 2-carboxyethyl- and 2-methyl-2-oxazoline, using a bisacrylamide as crosslinker. The polymerization was carried out in a mixture of water and ethanol at room temperature and was initiated by ammonium peroxodisulfate. The HG showed conformational transitions with variation of temperature and/or pH-value and as a function of hydrogel composition. This property was shown macroscopically as hydrogel contraction or expansion. The HG structures were characterized by high-resolution magic angle spinning (HRMAS) NMR spectroscopy. The thermal properties, in particular the lower critical solution temperatures, were determined by temperature-dependent HRMAS NMR measurements and differential scanning calorimetry. The pH responsibility was determined by swelling experiments in water at different pH values.

Details

Original languageEnglish
Pages (from-to)208-216
Number of pages9
Journal Designed monomers and polymers : an international journal on monomer and macromolecular synthesis
Volume17
Issue number3
Publication statusPublished - 3 Apr 2014
Peer-reviewedYes
Externally publishedYes

External IDs

Scopus 84887475122
ORCID /0000-0002-4531-691X/work/148607917

Keywords

Keywords

  • Graft copolymers, Hydrogels, Macromonomers, Networks, Stimuli-sensitive polymers, Swelling