• Number 307  |
• March 15, 2010

Measuring the speed of noble “bubbles”

Storing energy in batteries and improving the shelf life of pharmaceuticals are just two areas that could benefit from understanding supercooled liquids and the amorphous solids into which they form. Using a layer of noble gas "bubbles," scientists at DOE’s Pacific Northwest National Laboratory devised a straightforward way to measure how fast molecules diffuse in supercooled liquids. The scientists placed either krypton or argon atoms under an amorphous methanol layer, which was chilled to temperatures below the glass transition. Then, they measured how fast the atoms bubbled to surface. With this data, they calculated the diffusion rate at temperatures around 100 to 115K, well below the previous lowest temperature for obtaining diffusion for methanol, 252 K. This new method dramatically increases the temperature and dynamic range of diffusion measurements in supercooled liquids. Part of this research was done at EMSL, a national scientific user facility.

[Kristin Manke, 509.372.6011,
kristin.manke@pnl.gov]