Regensburg 2016 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 5: Nanomaterials I: Mechanics
MM 5.1: Vortrag
Montag, 7. März 2016, 10:15–10:30, H53
Chemical crosslinking inside an organic/inorganic nano-supercrystal — •Axel Dreyer1, Artur Feld2, Andreas Kornowski2, Ezgi D. Yilmaz1, Heshmat Noei3, Andreas Meyer2, Andreas Stierle3, Horst Weller2, and Gerold A. Schneider1 — 1Technische Universität Hamburg-Harburg, Institut für Keramische Hochleistungswerkstoffe — 2Universität Hamburg, Institut für Physikalische Chemie — 3DESY, NanoLab
Natural hard tissues like nacre are characterized by outstanding mechanical properties. The key to their behavior is the combination of hard inorganic and soft organic constituents on the nanoscale. Our approach is to synthesize a bio-inspired material by self-organization of organic-coated Fe3O4 nanoparticles into a well-ordered superstructure. The inorganic particles are separated by a layer of surfactants that is about one nanometer thick. Therefore, the organic molecules play a prominent role by providing cohesion in the material via strong coordinative bonding of functional groups to the particles surface as well as weak van der Waals bonding between adjacent molecules. To improve the mechanical properties, we substitute the weak van der Waals interaction by strong covalent bonds through thermally induced crosslinking of unsaturated surfactants performed in the solid composite, which yields values of up to 3.4 GPa, 60 GPa, and 630 MPa for microscale hardness, modulus, and strength, respectively. We will discuss which chemical processes take place in the organic phase. This knowledge enables a tailor-made synthesis of surfactants for optimization of the mechanical properties.