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SYPE: Symposium Polyelectrolytes

SYPE 1: Polyelectrolytes Poster

SYPE 1.9: Poster

Wednesday, March 28, 2007, 16:00–18:30, Poster B

Layer-by-layer Polyelectrolyte films containing magnetite nanoparticles: Construction and magnetic properties — •Marjolein Neeleman and Andreas Fery — Max-Planck-Institut für Kolloid und Grenzflächenforschung, Am Mühlenberg 1 14424 Potsdam

Magnetic ultrathin membranes are of interest for various applications ranging from data storage to the biomedical field. We have investigated the construction of such membranes using the well-established electrostatic layer-by-layer deposition. This method allows to build up nanoscale surface coatings by alternating adsorption of poly(allylamine hydrochloride) (PAH) and magnetite nanoparticles from aqueous solutions. We have characterized the dependence of the structure of these coatings on deposition parameters like salt concentration of the adsorption solution using atomic force microscopy and X-ray reflectivity. We find that depending on the deposition conditions both linear film growth and exponential film growth can be observed for this system. Finally, hollow magnetic capsules were produced by coating dissolvable core particles with multilayers and subsequently dissolving the particles under conditions that do not destroy the multilayer. With a magnetic balance the magnetic moment of the resulting microcapsules was studied. We find an almost linear increase of the magnetic moment with the number of bilayers applied to the cores, which demonstrates that our method allows producing membranes of well defined magnetization.