Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 43: Micro- and nanostructured magnetic materials

MA 43.3: Vortrag

Donnerstag, 4. April 2019, 10:00–10:15, H52

Field-induced deformation of nanorod-hydrogel composites — •Kerstin Birster, Rouven Schweitzer, Christoph Schopphoven, and Andreas Tschöpe — Universität des Saarlandes, Experimentalphysik, Campus D2.2, 66123 Saarbrücken

Shape-changing smart materials are able to reversibly deform in response to an external stimulus such as temperature, pressure, or electric and magnetic fields. An evident application is their use as active components in soft microactuators.

In the present study, we used ferromagnetic single domain nanorods as magnetic phase in cylindrical shaped polyacrylamide hydrogel composites. During polymerisation a magnetic texture was imprinted by alignment of the anisotropy axes in magnetic fields of predefined geometry. If the nanorods are directed perpendicular to the long cylinder axis, the composite is forced to a torsional deformation. A more complex spatially modulated alignment of the anisotropy axis into one half-space caused a sinusoidal bending of the composite filament. The specific deformation patterns were measured by video microscopy and data were analyzed assuming a continuum model with volume-distributed torques. Both examples demonstrate the potential of tuning the field induced deformation of magnetic composites which will be extended to a combined torsional bending motion. An alternative approach is the use of a magnetic gradient field to collect core-shell nanorods with adsorbed gelatin in a thin 2D multilayer.