title: Core-Shell Structure of Monodisperse Poly(ethylene glycol)-Grafted Iron Oxide Nanoparticles Studied by Small-Angle X-ray Scattering.
abstract: The promising applications of core-shell nanoparticles in the biological and medical field have been well investigated in recent years. One remaining challenge is the characterization of the structure of the hydrated polymer shell. Here we use small-angle X-ray scattering (SAXS) to investigate iron oxide core-poly(ethylene glycol) brush shell nanoparticles with extremely high polymer grafting density. It is shown that the shell density profile can be described by a scaling model that takes into account the locally very high grafting density near the core. A good fit to a constant density region followed by a star-polymer-like, monotonously decaying density profile is shown, which could help explain the unique colloidal properties of such densely grafted core-shell nanoparticles. SAXS experiments probing the thermally induced dehydration of the shell and the response to dilution confirmed that the observed features are associated with the brush and not attributed to structure factors from particle aggregates. We thereby demonstrate that the structure of monodisperse core-shell nanoparticles with dense solvated shells can be well studied with SAXS and that different density models can be distinguished from each other.
authors: Department of Material Sciences and Process Engineering, University of Natural Resources and Life Sciences , Vienna, Peter-Jordan-Straße 82, A-1190 Vienna, Austria.
authors: Tilman A
authors: TA
authors: Grünewald
authors: Department of Nanobiotechnology, University of Natural Resources and Life Sciences , Vienna, Muthgasse 11, A-1190 Vienna, Austria.
authors: Andrea
authors: A
authors: Lassenberger
authors: Department of Nanobiotechnology, University of Natural Resources and Life Sciences , Vienna, Muthgasse 11, A-1190 Vienna, Austria.
authors: Peter D J
authors: PD
authors: van Oostrum
authors: Department of Material Sciences and Process Engineering, University of Natural Resources and Life Sciences , Vienna, Peter-Jordan-Straße 82, A-1190 Vienna, Austria.
authors: Harald
authors: H
authors: Rennhofer
authors: Department of Nanobiotechnology, University of Natural Resources and Life Sciences , Vienna, Muthgasse 11, A-1190 Vienna, Austria.
authors: Ronald
authors: R
authors: Zirbs
authors: Faculty of Physics, University of Vienna , Boltzmanngasse 5, A-1090 Vienna, Austria.
authors: Barbara
authors: B
authors: Capone
authors: Department of Nanobiotechnology, University of Natural Resources and Life Sciences , Vienna, Muthgasse 11, A-1190 Vienna, Austria.
authors: Iris
authors: I
authors: Vonderhaid
authors: Institute for Inorganic Chemistry, Graz University of Technology , Stremayrgasse 9/V, A-8010 Graz, Austria.
authors: Heinz
authors: H
authors: Amenitsch
authors: Department of Material Sciences and Process Engineering, University of Natural Resources and Life Sciences , Vienna, Peter-Jordan-Straße 82, A-1190 Vienna, Austria.
authors: Helga C
authors: HC
authors: Lichtenegger
authors: Department of Nanobiotechnology, University of Natural Resources and Life Sciences , Vienna, Muthgasse 11, A-1190 Vienna, Austria.
authors: Erik
authors: E
authors: Reimhult