Web Release Date: October 25,
Polyelectrolyte/magnetite Nanoparticle Multilayers: Preparation and Structure Characterization
and
Max-Planck Institute of Colloids and Interfaces, Golm/Potsdam, D-14476, Germany, Faculty of Nano- and Biomedical Technology, Saratov State University, Saratov, 410012, Russia, Department of Materials, Queen Mary University of London, E1 4NS, London, U.K., and Federal Institute for Materials Research and Testing, Berlin, D-12489, Germany
Received April 3, 2007
In Final Form: September 5, 2007
Abstract:
Polyelectrolyte composite planar films containing a different number of iron oxide (Fe3O4) nanoparticle layers have been prepared using the layer-by-layer adsorption technique. The nanocomposite assemblies were characterized by ellipsometry, UV-vis spectroscopy, and AFM. Linear growth of the multilayer thickness with the increase of the layer number, N, up to 12 reflects an extensive character of this parameter in this range. A more complicated behavior of the refractive index is caused by changes in the multilayer structure, especially for the thicker nanocomposites. A quantitative analysis of the nanocomposite structure is provided comparing a classical and a modified effective medium approach taking into account the influence of light absorption by the Fe3O4 nanoparticles on the complex refractive index of the nanocomposite and contributions of all components to film thickness. Dominant influence of co-adsorbed water on their properties was found to be another interesting peculiarity of the nanocomposite film. This effect, as well as possible film property modulation by light, is discussed.
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