Functional selenium modified microgels: temperature-induced phase transitions and network morphology

Kok H. Tan, Dan E. Demco*, Radu Fechete, Andrij Pich*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

11 Citations (Web of Science)

Abstract

Microgels that host selenium and mimic the structure of the enzyme glutathione peroxidase are of great interest for biotechnological and catalytic applications. For this purpose selenium-functionalized thermoresponsive poly(N-vinylcaprolactam) (PVCL) microgels with cleavable diselenide crosslinks have been investigated. Thermodynamic and morphological parameters characterizing the temperature-induced phase transitions of dual crosslinked PVCL microgels were obtained using dynamic light scattering (DLS), H-1 high-resolution magic-angle sample-spinning (MAS) NMR spectroscopy, and transverse magnetization (T-2) NMR relaxometry. Quantities obtained from Flory-Rehner theory, a two-state model and Boltzmann sigmoidal function were used to relate the phase transitions of the dual crosslinked microgels to the transition temperature, entropy, temperature width of the phase transition, Flory interaction parameters, average number of strands, polymer volume fraction of the collapsed microgels, core-corona fractions and chain dynamics. The morphology of the selenium modified microgels after the oxidation and reduction processes was investigated by H-1 T-2 NMR and further correlated with the crosslink density.

Original languageEnglish
Pages (from-to)3227-3240
Number of pages14
JournalSoft Matter
Volume15
Issue number15
DOIs
Publication statusPublished - 21 Apr 2019

Keywords

  • POLY(N-ISOPROPYLACRYLAMIDE) GELS
  • POLYMERS
  • POLY(N-VINYLCAPROLACTAM)
  • NANOGELS
  • KINETICS
  • BEHAVIOR
  • H-1-NMR
  • OXIDE
  • CORE

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