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Ambient - Pressure Silica Aerogel Films

Published online by Cambridge University Press:  28 February 2011

Sai S. Prakash ,
C. Jeffrey Brinker ,
Alan J. Hurd  and
Sudeep M. Rao
Sai S. Prakash
Affiliation:
University of New Mexico/Sandia National Laboratories Advanced Materials Laboratory, Albuquerque, NM 87106 (USA)
C. Jeffrey Brinker
Affiliation:
University of New Mexico/Sandia National Laboratories Advanced Materials Laboratory, Albuquerque, NM 87106 (USA) Ceramic Synthesis and Inorganic Chemistry Department 1846, Sandia National Laboratories, Albuquerque, NM 87185 (USA)
Alan J. Hurd
Affiliation:
Ceramic Processing Science Department 1841, Sandia National Laboratories, Albuquerque, NM 87185 (USA)
Sudeep M. Rao
Affiliation:
University of New Mexico/Sandia National Laboratories Advanced Materials Laboratory, Albuquerque, NM 87106 (USA)
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Abstract

Very highly porous (aerogel) silica films with refractive index in the range 1.006-1.05 (equivalent porosity 98.5-88%) were prepared by an ambient-pressure process1,2. It was shown earlier using in situ ellipsometric imaging1 that the high porosity of these films was mainly attributable to the dilation or “springback” of the film during the final stage of drying. This finding was irrefutably reconfirmed by visually observing a “springback” of >600% using environmental scanning electron microscopy (ESEM). Ellipsometry and ESEM also established the near 100% reversibility of aerogel film deformation during solvent intake and drying. Film thickness profile measurements (near the drying line) for the aerogel, xerogel and pure solvent cases are presented from imaging ellipsometry. The thickness of these films (crack-free) were controlled in the range 0.1-3.5 μm independent of refractive index.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 371: Symposium W1 – Advances in Porous Materials , 1994 , 205
Copyright
Copyright © Materials Research Society 1995

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References

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