Dresden 2011 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 34: Poster: Elastomers and Gels

CPP 34.12: Poster

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

Isotropic and uniaxial ferrogels with Ni nanorods as magnetic phase — •Philipp Bender, Andreas Tschöpe, and Rainer Birringer — Universität des Saarlandes, Saarbrücken, Deutschland

The present study focuses on the synthesis and characterization of gelatine-based ferrogels with Ni nanorods as magnetic phase. With diameters < 64 nm and aspect ratios > 3 the nanorods are uniaxial ferromagnetic single-domain particles. In the resulting ferrogels the nanorods can rotate in field direction by applying a homogenous magnetic field, working against the mechanical torque, which is caused by the shear deformation of the gel matrix.The nanorods itself were synthesized by electro-deposition of Ni into porous alumina templates, released into aqueous dispersion by dissolution of the alumina layer and further processed to gelatine-based ferrogels. The nanorods are mechanically linked to the polymer network and exhibit - without further pretreatment - an isotropic orientation distribution. However, applying an external homogenous magnetic field during the gelation process enabled the preparation of magnetically textured ferrogels. In the current work angular-dependent static magnetization measurements were used to analyze the rotation of the nanorods in soft uniaxial ferrogels, using a hard uniaxial ferrogel as reference. The elastic properties of the corresponding isotropic ferrogel were characterized using a theoretical model, which is based on the Stoner-Wohlfarth-model.