Glass softening, crystallization, and vaporization of nano-aggregates of Amorphous Solid Water: Fast Scanning Calorimetry studies

Abstract

Fast scanning calorimetry (FSC) was employed to investigate glass softening dynamics in amorphous solid water (ASW) nano-aggregates with thicknesses ranging from 2 to 20 nm. ASW nano-aggregates were prepared by vapor-deposition on the surface of a tungsten filament near 141 K and then heated at a rate of 100 kK/s. The resulting thermogram complex endo- and exothermal features were analyzed using a simple model. The results of the analysis show that glass softening of ASW nano-aggregates takes place at 160 K and vaporization of ASW nano-aggregates can take place at temperatures as low as 185 K. The results of these studies are discussed in conjunction with results of past studies of glass softening dynamics in water in various confining geometries.