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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 42: French-German Session: Nanomaterials, Composites and Hybrids II
CPP 42.2: Talk
Wednesday, March 11, 2026, 17:30–17:45, ZEU/0260
Plasmonic core-shell microgels: The role of the core size — •Déborah Feller1,2, Julian Oberdisse3, Sylvain Prévost4, and Matthias Karg1 — 1Physical Chemistry of Functional Polymers, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany — 2Physical Chemistry: Colloids and Nanooptics, Heinrich Heine University Düsseldorf, Düsseldorf, Germany — 3Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, Montpellier, France — 4Large Scale Structures, Institut Laue-Langevin, Grenoble, France
Gold-poly-N-isopropylacrylamide (Au PNIPAM) core-shell microgels are interesting due to the localized surface plasmon resonance (LSPR) of the cores. The LSPR position strongly depends on the core size. Compared to other core-shell microgels, Au cores can be precisely overgrown in the shell in situ. Although cores grow in size, the overall hydrodynamic diameter of the microgels does not change. It is not known how the structure of the shell changes during the overgrowth.
Here, we are analyzing Au-PNIPAM microgels with two crosslinker densities. The cores are overgrown from 14 nm in diameter to nearly 100 nm. We perform small-angle X-ray and neutron scattering (SAXS/SANS) to study the respective form factors. SAXS provides information about the cores and SANS about the shell. We also investigate temperature-dependent changes in the microgel by SANS. Additionally, extinction spectra are recorded to study the optical properties. We perform simulations of the different microgels to get information on the internal structure of the shell and the polymer distribution.
Keywords: core-shell microgels; in situ overgrowth; small-angle neutron scattering; plasmonic