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

TL;DR

This study uses fast scanning calorimetry to explore the thermal behaviors of nano-sized amorphous solid water, revealing specific softening and vaporization temperatures and comparing these findings with previous research on water in confined spaces.

Contribution

It provides new insights into the glass softening and vaporization temperatures of nano-aggregates of amorphous solid water using high-rate calorimetry.

Findings

Glass softening occurs at 160 K.

Vaporization can occur at 185 K.

Results align with previous studies on confined water.

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.