Premelting of Ice at Interfaces: A Nano-Phenomenon with Giga-Impact
Prof. Dr. Helmut Dosch (Max Planck Institute for Metals Research, Stuttgart)

Well below 0oC, ice develops a nanosized water-like layer at its free surface and in contact with geological material. This surface and interface premelting phenomenon has many, most important ramifications for our biosphere, ranging from the formation of snowflakes, the charging of thunderstorms and the chlorine chemistry in polar stratospheric clouds to the mechanical stability of ice-silica interfaces, clay and permafrost.

While the ice premelting is a well-established surface phenomenon, many details, in particular the relevant geological factors which influence the onset of premelting as well as the growth of the nanosized quasi-water layer, are not understood on a microscopic level.

Modern analytical insitu techniques as provide by 3rd generation Synchrotron radiation sources allow one today to investigate the premelting of ice with high resolution and reproducibility and to unravel the role of roughness and of impurities. In this lecture a review the current state of understanding of ice premelting and the latest experiment on ice-silica interfaces which disclosed rather intriguing new features of the interfacial water layer which shed also a new light onto the water structure and the ice phase diagram in general.