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C. Rill, J. Peters, G. Kickelbick:
"NMR RELAXIVITY OF SURFACE-MODIFIED NEODYMIUM HYDROXIDE AND OXIDE NANORODS";
Vortrag: Imagination 2007, Erasmus Medical Center, Rotterdam; 14.03.2007.

Nanoparticles based on rare earth metals have great potential for optical or magnetic applications and materials owing to the combination of their small size with the lanthanides´ special electronic structure. By a hydrothermal approach crystalline neodymium hydroxide nanorods were prepared. Transmission electron microscopy (TEM) showed that the nanorods have a high-aspect ratio with a diameter of 15-30 nm and a length of up to a few micrometers. The nanorods were altered in two ways: 1) by surface modification with phenylphosphonic acid and 2) by transformation of the hydroxidic nanorods into neodymium oxide by thermal treatment. Electron microscopy and IR spectroscopy confirmed that the particle morphology as well as the organic surface modification were not degraded by the heat treatment. Both the modified and the unmodified nanorods were additionally subjected to calcination at 950°C.
To examine the nanorods´ potential as contrast agents for magnetic resonance imaging the transversal relaxivity (R2) in aqueous suspensions of the nanorods was investigated. It was found that the surface modification led to an increase of the relaxivity, while the calcined nanorods exhibited the highest relaxivity. The data was fitted well by a model which considers a combination of the static dephasing regime and a diffusion model.