The permeation of rare-gas atoms through deeply supercooled metastable liquid methanol films is used to probe the diffusivity. The technique allows for measurement of supercooled liquid self-diffusion at temperatures just above the glass transition. The diffusivity near the glass transition is characterized by an activation energy and prefactor that are seven and 1030 times greater, respectively, than those of the room temperature liquid. The temperature dependence of the diffusivity is well-described by a Vogel-Fulcher-Tamman (VFT) equation. These new measurements, their kinetic parameters, and temperature dependence provide clear evidence that methanol is a fragile liquid.
Revised: February 15, 2010 |
Published: December 11, 2009
Citation
Matthiesen J., R.S. Smith, and B.D. Kay. 2009.Using Rare Gas Permeation to Probe Methanol Diffusion near the Glass Transition Temperature.Physical Review Letters 103, no. 24:Article Number: 245902.PNNL-SA-67478.