SKM 2021 – wissenschaftliches Programm
CPP 8.14: Poster
Mittwoch, 29. September 2021, 17:30–19:30, P
Magnetic response of CoFe2O4 nanoparticles confined in PNIPAM-microgel networks — •Joachim Landers1, Marcus Witt2, Juri Kopp1, Stephan Hinrichs3, Soma Salamon1, Birgit Hankiewicz3, Regine von Klitzing2, and Heiko Wende1 — 1Faculty of Physics and CENIDE, University of Duisburg-Essen — 2Department of Physics, TU Darmstadt — 3Institute of Physical Chemistry, Hamburg University
Magnetic microgels of CoFe2O4 nanoparticles embedded in N-isopropylacrylamid (NIPAM) hydrogel exhibit versatile response behavior to external stimuli, combining the characteristic NIPAM volume phase transition (VPT) with tunable response to external magnetic fields determined by the local surrounding of the magnetic nanoparticles. In addition to conventional magnetic microgels, samples modified with allyl mercaptan affecting their swelling behavior were examined regarding their internal structure and magnetization dynamics. For an in-depth analysis of the nanoparticle confinement governing the microgels’ magnetic response, detailed mappings of frequency- and temperature-dependence of the microgels’ magnetic AC-susceptibility were recorded, enabling the precise resolution of Néel-type and Brownian dynamics as well as the extraction of nanoparticle confinement parameters. We observe a distinct reaction of nanoparticle dynamics across the VPT, showing characteristic differences when comparing conventional and allyl mercaptan - modified microgels. Funding by the DFG via SPP 1681 (project WE 2623/7-3, FI 1235/2-2 and KL 1165/18-1) is gratefully acknowledged.