Measuring Diffusivity in Supercooled Liquid Nanoscale Films using Inert Gas Permeation: II. Diffusion of AR, KR, Xe, and CH4 through Methanol

Journal Article · Sun Nov 07 04:00:00 EST 2010 · Journal of Chemical Physics, 133(17):174505-11

DOI:https://doi.org/10.1063/1.3497648· OSTI ID:1000123

Matthiesen, Jesper; Smith, R Scott; Kay, Bruce D

We present an experimental technique to measure the diffusivity of supercooled liquids at temperatures near their Tg. The approach uses the permeation of inert gases through supercooled liquid overlayers as a measure of the diffusivity of the supercooled liquid itself. The desorption spectra of the probe gas is used to extract the low temperature supercooled liquid diffusivities. In the preceding companion paper, we derived equations using ideal model simulations from which the diffusivity could be extracted using the desorption peak times for isothermal or peak temperatures for TPD experiments. Here, we discuss the experimental conditions for which these equations are valid and demonstrate their utility using amorphous methanol with Ar, Kr, Xe, and CH4 as probe gases. The approach offers a new method by which the diffusivities of supercooled liquids can be measured in the experimentally challenging temperature regime near the glass transition temperature.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1000123
• Report Number(s): PNNL-SA-74281; 24694; 39898; KC0301020
• Journal Information: Journal of Chemical Physics, 133(17):174505-11, Journal Name: Journal of Chemical Physics, 133(17):174505-11 Journal Issue: 17 Vol. 133; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
DESORPTION
DIFFUSION
Environmental Molecular Sciences Laboratory
GASES
GLASS
METHANOL
PROBES
SPECTRA
TRANSITION TEMPERATURE