Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 5: New Materials
CPP 5.7: Vortrag
Montag, 25. Februar 2008, 11:45–12:00, C 230
Astonishing change of the hypersonic behaviour in a commercial gel due to supercooling of the sol-gel transition — •Ulrich Müller1, Martine Philipp1, Jan Kristian Krüger1, Roland Sanctuary1, Bartosz Zielinski1, Jörg Baller1, Ravindrakumar Bactavatchalou1, and Patrick Alnot2 — 1Université du Luxembourg, LPM, Campus Limpertsberg, L-1511 Luxembourg — 2Université Henri Poincaré - Nancy I, Nancy, France
The sol-gel transition in the commercial gel Kaisers glycerol gelatine (MERCK), composed of water, glycerol and gelatine is based on the formation of percolated physical network of the gelatine molecules. The measurements are performed by Brillouin spectroscopy for the determination of the hypersonic properties, polarimetry for the investigation of the network formation and refractometry. It will be shown that the hypersonic properties of that gel strongly depends on the thermal history of the material on one hand but that no special acoustic anomaly is found in the vicinity of the temperature of gelation on the other. Although differently supercooled gel states are clearly in thermodynamic non-equilibrium they did not show relaxations towards their equilibrium state. In agreement with that result different glass forming behaviour was observed.