Dresden 2017 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 68: Hydrogels and Microgels II
CPP 68.2: Vortrag
Freitag, 24. März 2017, 10:30–10:45, ZEU 260
Magneto-optical and magneto-rheological properties of a physical hydrogel based on 12-hydroxystearic acid — Hajnalka Nádasi1, Ralf Stannarius1, Peter Salamon2, Tamas Börzsönyi2, and •Alexey Eremin1 — 1Institute of Experimental Physics, Otto von Guericke University Magdeburg, Universitätsplatz 2, 39016 Magdeburg, Germany — 2Wiegner Research Centre for Physics, Institute for Solid State Physics and Optics, Budapest, H-1525, Hungary
We investigate magneto-responsive physical ferrogels based on 12-hydroxystearic acid in dodecane, doped with commercial magnetic nanoparticles APG 935. The gelator molecules form a hydrogen-based gel network at room temperature. The pure gels exhibit extraordinary helical filament nanostructures similar to those of the HNF(B4) liquid crystal phase formed by bent-core mesogens. The rheological behaviour of the ferrogel is found to be strongly dependent on the preparation protocol. The ferrogels prepared in a magnetic field exhibit lower storage modulus, which can be attributed to rearrangements of the magnetic particles embedded in the gel matrix. At higher shear rates, a gel-sol transition occurs. In a magnetic field, the interaction between the magnetic particles and the matrix lead to an increase of both storage and loss moduli.
The authors acknowledge the support by DFG (SPP 1681, STA 425/36-2)