Oxygen-Controlled Phase Segregation in Poly(N‑isopropylacrylamide)/Laponite Nanocomposite Hydrogels

Research output: Contribution to journalArticle


The combination of nanoparticles and polymers into nanocomposite
gels has been shown to be a promising route to creating soft materials with new or improved properties. In the present work, we have made use of Laponite nanoparticles in combination with a poly(N-isopropylacrylamide) (PNIPAAM)polymer and describe a phenomenon taking place during the polymerization and gelling of this system. The presence of small amounts of oxygen in the process induces two distinctly separated phases, one polymer-rich and one polymer-deficient water−clay phase. Complex interactions among clay, oxygen, and the polymer are found to govern the behavior of these phases. It is also observed that the initial clay concentration can be used to control the volume fraction of the
polymer-deficient phase directly. The dynamics of the phase boundary is found to be dependent on water penetration and in general to exhibit non-Fickian behavior. An approach using video recording to monitor hydrogel swelling is also presented, and its advantages are addressed.


  • Henrik Mauroy
  • Rozynek Zbigniew
  • Tomás Plivelic
  • Jon Otto Fossum
  • Geir Helgesen
  • Kenneth D. Knudsen
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Sciences
  • Natural Sciences


  • Nanocomposite hydrogel, clay, Laponite, PNIPAAM, phase segregation, small angle x-ray scattering
Original languageEnglish
Pages (from-to)371-379
Publication statusPublished - 2013
Publication categoryResearch