Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 16: Poster I

MA 16.33: Poster

Dienstag, 12. März 2013, 10:30–13:30, Poster D

Characterization of the elastic properties of hydrogels using nickel nanorods as probes — •Philipp Bender, Andreas Tschöpe, and Rainer Birringer — Universität des Saarlandes, Saarbrücken, Germany

With diameters below 42 nm, Ni nanorods are uniaxial ferromagnetic single-domain particles. The nanorods are synthesized by electrodeposition of nickel into porous alumina templates and after several preparation steps dispersed into gelatin gels matrices. Applying a homogeneous magnetic field during gelation results in magnetically textures ferrogels. When the gels are placed in a homogeneous magnetic field, the magnetic torque causes a rotation of the magnetic moments of the rods in field direction. The alignment can occur by a rotation out of the long rod axis working against shape anisotropy or by a rotation of the rods itself, which is restricted by the surrounding elastic network. In a static homogenous magnetic field the magnetic torque, the counteracting torque due to shape anisotropy and the mechanical torque, caused by the shear deformation of the surrounding gel matrix, are at equilibrium. This equilibrium condition was used to develop several methods to characterize the elastic properties of soft hydrogel matrices by magnetization measurements using nickel nanorods as probes. In the present study the initial susceptibilty of the magnetization curves is evaluated in order to determine the shear modulus.