Interfacial premelting of ice in nano composite materials

by Prof. Markus Mezger (Max Planck Institute for Polymer Research, Mainz)

Monday 9 Dec 2019, 14:30 → 15:30 Europe/Berlin

PH HS 3 (Physics Department)

The surface melting of ice, discovered by Faraday in 1859, is one of the best-known interface-induced phase transitions. However, the structural and dynamic properties of liquid water within this interfacial premelting layer is still under debate. We study premelting in ice/clay nano composites by quasi elastic neutron scattering and high energy X-ray diffraction. Using well defined and characterized ice/mineral composite samples, our work bridges the gap between studies on single crystalline model interfaces and naturally occurring soils and permafrost. Significant differences in the growth of the premelting layer and its mobility are found for the charged vermiculite, uncharged kaolin, and more hydrophobic talc. This indicates that besides confinement, intermolecular interactions between the water molecules and the mineral surfaces play an important role for the water mobility in ice/clay nanocomposites.