Dresden 2011 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 36: Poster: Nanoparticles and Composite Materials

CPP 36.8: Poster

Wednesday, March 16, 2011, 17:00–19:00, P2

Synthesis and characterization of silica-encapsulated nanorods — •Nina Haselmaier, Philipp Bender, Andreas Tschöpe, and Rainer Birringer — Universität des Saarlandes, Saarbrücken, Deutschland

Ni nanorods with diameters ranging from 15-30 nm and aspect ratios > 3 are uniaxial ferromagnetic single domain particles. The unique magnetic properties translate into rheological properties in colloidal dispersions with perspective applications in microbiology. However, due to the strong dipolar interaction, both steric and electrostatic stabilization are necessary to prevent the nanoparticles from agglomeration even in dilute suspensions. In the present study Ni nanorods were synthesized by current-pulsed electro-deposition of Ni into hexagonally ordered porous alumina-templates. Afterwards they were released from the templates by dissolution of the alumina layer in sodium hydroxide (NaOH), to which PVP (polyvinyl-pyrrolidone) was added as surfactant. A thorough washing procedure resulted in stable aqueous colloidal dispersions of the Ni nanorods. SEM (scanning electron microscopy) - and TEM (transmission electron microscopy) - characterization of the nanorods reveals that their surrounding PVP-layer is about 6 nm thick. The main purpose of the PVP-layer is to avoid the formation of strong aggregates in the dispersion during sample preparation. The focus of the present study was to replace the organic PVP-layer by a mechanically rigid inorganic silica shell in order to increase the potential for surface functionalization of the nanoparticles.