Berlin 2008 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 29: Polymerphysics I

CPP 29.3: Talk

Thursday, February 28, 2008, 10:00–10:15, C 130

On the creation of dielectric interphases in composites containing nano- and micro- particles. — •Béatrice Hallouet¹, Pauline Desclaux¹, Bernd Wetzel², Alois K. Schlarb², and Rolf Pelster¹ — ¹Fachrichtung 7.2 Experimentalphysik, Universität des Saarlandes Campus E 2.6 D-66 123 Saarbrücken Germany — ²Institut für Verbundswerkstoffe GmbH (IVW) Erwin-Schrödinger-Straße, Geb. 58 D-67 663 Kaiserslautern Germany

We investigate composites consisting of magnetic particles (Fe3O4) in a polymer matrix (an epoxy resin) using broadband dielectric spectroscopy in a frequency range between 50 Hz and 1 GHz. Especially, we compare systems containing nano-particles (mean diameter between 20 and 30 nm) and micro-particles (mean diameter about 5 μm ). Temperature-dependent measurements allow us to characterize a molecular relaxation of the matrix material, that is modified by the presence of the dispersed particles. For a model-free and non ambiguous analysis of these effects we use the spectral representation of Bergman [1]. We discuss the results in terms of modified interactions at the interfaces of the particles and check whether they depend on the microstructure of the composites and/or on the surface-to-volume ratio of the particles.

[1] B. Hallouet, B. Wetzel, and R. Pelster, "On the dielectric and magnetic properties of nanocomposites " , JNM in press.