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DY: Dynamik und Statistische Physik

DY 13: Ferrofluide

DY 13.5: Talk

Monday, March 11, 2002, 12:45–13:00, H3

Multiphase nanostructure of magnetic liquids — •Martin Kammel, Armin Hoell, and Albrecht Wiedenmann — Hahn-Meitner-Institut, Glienicker Strasse 100, 14109 Berlin

In Ferrofluids the magnetic nanosized cores are stabilized against coagulation by coating with different surfactants. We investigate presently new biocompatible water-based ferrofluids with Magnetite, Fe3O4, as core and Laurin-acid and Marlipal as surfactants. Small Angle Neutron Scattering was used to determine the microstructure of the complicated system. With the aid of a combined contrast variation using polarised neutrons (SANSPOL) and different mixtures of H2O/D2O as solvents we were able to evaluate composition and size distributions of core and shell as well as the magnetisation of the nanosized cores. Depending on concentration micelles and aggregates were found to be formed beside the composite core-shell particles and free surfactant molecules. The corresponding size distributions and volume fractions have been determined.