Berlin 2015 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 50: P15: Polymers and Fields

CPP 50.3: Poster

Wednesday, March 18, 2015, 10:00–13:00, Poster A

Multifunctional Magnetic Hydrogel Particles — •Marcus Witt, Sebastian Backes, and Regine von Klitzing — Technische Universität Berlin, Physikalische Chemie, Germany

Microgels made of N-isopropylacrylamide (NIPAM) exhibit a volume phase transition temperature (VPTT) which leads to reversible swelling in water. The swelling and shrinking depends on the temperature, and with addition of different co-monomers also on the pH and ionic strength.

With the incubation of magnetic nanoparticles (MNP) such as cobalt ferrite we can obtain ferrogels which are also responsive to external magnetic fields.

Most publications about ferrogels are based on core/shell particles. In contrast, we aim for a homogenous distribution of MNP over the whole hydrogel, so that the ferrogel should respond uniformly to the applied magnetic field. Therefore, we synthesized a homogenously crosslinked hydrogel by a constant feeding of the reactant. The MNP are then incubated by mixing aqueous solutions of hydrogel and MNP.

We were able to show that the initial thermoresponsive properties of the hydrogel are preserved for ferrogels both in bulk solution and adsorbed on a Si-surface.

Measurements of adsorbed ferrogel particles in an external magnetic field parallel to the surface have been carried out by AFM. First results show an increase of particle height and volume with an increasing magnetic field, whereas the area of the particle changes only slightly.