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M. Litschauer, M.-A. Néouze:
"Construction of metal oxide nanoparticles 3-D networks through ionic connectors";
Talk: E-MRS Spring Meeting 2010, Strasbourg, France; 2010-06-07 - 2010-06-11.

We recently developed an original method to synthesize 3-D networks consisting of metal oxide nanoparticles, through the introduction of functionalized ionic linkers. The imidazolium ionic linkers resemble ionic liquids, regarding some of their physicochemical properties. Recent publications pointed out the powerful synergy of ionic species with nanoparticles. The presentation will detail the network synthesis. First silica nanoparticles were synthesized via the Stöber process and afterwards functionalized with silanes bearing either an alkyl halide or an imidazol end group. Then the construction of the network was induced by a nucleophilic substitution reaction. The formation of a covalent bond between the nanoparticles was investigated with thermogravimetric analysis (TGA), solid state nuclear magnetic resonance (NMR), transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The results evidenced the formation of 3-D nanoparticles networks. Exchange of the halide anion of the system to bigger anions, PF6-, BF4- or Tf2N-, was performed and the changes on the physicochemical properties of the material were studied. The replacement follows an anion metathesis reaction, monitored by X-ray powder diffraction (XRD) and solid state NMR. It turned out that ionic linked silica nanoparticles networks were easily obtained. Moreover, anion exchange experiments allow tailoring of the physicochemical properties of such new inorganic-organic hybrid materials.

Project Head Marie-Alexandra Néouze:
Ionische Verknüpfung von Nanopartikeln