MainPage:Nuclear:Summer2012:AerogelCoating

⇐ Back to Summer 2012 page

⇐ Back to the Main_Page

Aerogel Yellowing

We have noticed some yellowing in some select tiles of our Aerogel inventory. This could be due to Aging, Radiation Damage, Water (could tie into hydrophobic properties), or perhaps fine particulates in the air. In any case, detailed chemical analysis will be conducted by Dr. Marek Brandys of VSL. I delivered the samples (1.01, yellow 1.03, "good" 1.03) to Dr. Brandys on 6/27. Will post his results A.S.A.P.

Here is a picture that shows the yellowing.

Results of initial analysis of the tile samples (7/30/12):

• Optical: Blue-ish color of aerogel due to Raleigh scattering, yellow-ish color could be due to Mie scattering from pores in the material
  • But if that is the case then not clear why one would observe yellow color only in selected tiles

• Temperature: heating the aerogel sample seems to restore the transparency, i.e., eliminate the yellow-ish coloring
  • In general, this effect of "aerogel baking" is known and discussed in the literature (see paper by Henning and Svensson, Physica Scripta, Vol. 23, 697-702, 1981.)
  • Interesting is that manufacturer claimed that baking would not be necessary with the special "coating" they applied to the tiles - is the coating not effective anymore?

• Chemical composition: trying to set up a non-destructive Raman scanning test