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Measuring Tg in Ultra-Thin Polymer Films With an Excimer Fluorescence Technique.


pdf icon Measuring Tg in Ultra-Thin Polymer Films With an Excimer Fluorescence Technique. (460 K)
White, C. C.; Migler, K. B.; Wu, W. L.

Polymer Engineering and Science, Vol. 41, No. 9, 1497-1505, September 2001.

Keywords:

polymer films; fluorescence; temperature

Abstract:

An excimer fluorescence technique has been applied to the measurement of Tg of ultra-thin polystyrene films. This technique utilizes an excimer-forming molecule with fluorescent emission in two wavelength bands. The intensity ratio of these bands is a sensitive measure of local viscosity. This technique has been applied to five polystyrene films in the thickness range of 25 nm to 200 nm supported on quartz substrates. The observed Tg for the five ultra-thin polymer films was similar to the bulk Tg with no observed dependence upon thickness. Additionally, the Tg determined for each film did not show any dependence upon thermal history.