Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Poster: Nanoparticles and Composite Materials
CPP 12.5: Poster
Montag, 11. März 2013, 17:30–19:30, Poster C
Synthesis and characterization of silica-encapsulated Ni nanorods — •Florian Krämer, Andreas Tschöpe, and Rainer Birringer — Universität des Saarlandes, Saarbrücken
Ni nanorods are uniaxial ferromagnetic particles which can be used in nanorheology to probe local viscoelastic properties of soft matter. The present study is focused on the encapsulation of the nanorods by a silica layer which provides a well-defined interface for subsequent surface functionalization. Alumina templates with hexagonally arranged pores were synthezised by two step anodization of aluminum. The alumina-layer was separated by a voltage reversal technique. The barrier oxide at the pore-bottom was dissolved by chemical etching resulting in free-standing mesoporous membranes with completely open pore morphology. The whole surface of the membrane including the porewalls was coated with a thin silica layer by atomic layer deposition. Ni nanorods were synthesized by direct current electro-deposition of Ni into the pores. The filled templates were characterized by static magnetization measurements revealing a coercivity of µ0HC=56 mT. Afterwards the rods were released from the template by dissolution of the alumina in NaOH. Transmission electron microscopy revealed a rod diameter of 60 nm and a thickness of the silica layer of 3 nm. The anisotropic optical properties of the rods which are the physical basis for magneto-optical rheometry, were investigated with regards to the influence of the silica layer and the size of the nanorods.