Berlin 2015 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 43: P8: Nanoparticles and Compsite Materials
CPP 43.18: Poster
Mittwoch, 18. März 2015, 10:00–13:00, Poster A
SAXS and NEXAFS characterization of dispersions with magnetic nanoparticles (ferrofluids) — •Christian Gollwitzer1, Raul Garcia Diez1, Michael Krumrey1, and Norbert Buske2 — 1Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany — 2MagneticFluids, Berlin, Köpenicker Landstrasse 203, 12437 Berlin, Germany
Ferrofluids contain magnetic nanoparticles (like magnetite or maghemite) with superparamagnetic properties [1]. Aqueous ferrofluids with different crystal sizes between 5 nm and 10 nm (TEM) and hydrodynamic diameters between 20 nm and 200 nm (DLS) were prepared. On the one hand, the particles were electrostatically stabilized towards aggregation showing a high positive zeta potential. On the other hand, the particles were covered with fruit acids (i.e. citrate) indicating a negative zeta potential at a neutral pH value.
SAXS and NEXAFS measurements were carried out at the four-crystal monochromator (FCM) beamline of PTB at the synchrotron radiation facility BESSY II in Berlin to determine the mean size and size distribution of the primary particles, the size and fractal dimension of the agglomerates and the oxidization state of the nanoparticles. It was found, that the used ferrofluids are stable for at least several months from preparation.
[1] Rosensweig, R. 1987 Magnetic fluids. Ann. Rev. Fluid Mech. 19, 437–463