°•. Orgins
Aerogels
were first discovered in 1931 by American chemist Samuel S. Kistler who
was trying to prove that a gel in its dried form contained a continuous
solid interwoven network that contained the same geometry as a wet gel.
However the problem was figuring out how to remove the liquid within
the gel without destroying the brittle solid network that
made up the outer portion of the gel.
°•.
Continued...
The first Aerogels produced
were silica gels, in which Kistler attempted to raise the water within
the gel to a supercritcal point in an attempt
to evaporate the water leaving only the solid shell of the gel in tact.
After several trial and error attempts altering different components
Kistler replaced the water within the gel with alcohol and converted it
to a supercritical fluid.by raising the temperature and pressure.
This allowed the alcohol to be
vented and still left the structure of the silica shell in place, thus
creating the first Aerogel.
°•.
Progress...
- 1940's- Kistler then created
several patents for making various other
forms of the Aerogel, which included Silica, Alumina, Chromia, Tin, and
Carbon Aerogels. Then in the Early 1940's he began trying to
commercialize his invention and signed a contract with Monsanto Corp.
and began marketing Silica Aerogel. However do to the cost and the fact
that the prototype Aerogels were still brittle the marketing fell
through and Aerogel disappeared off the radar
- 1970's-The French government
approaches Stanislaus Teichner at University Claud Bernard, Lyon
seeking a method for storing oxygen and rocket fuels in porous
materials and NASA gets involved. The current knowledge of Aerogels was
not good enough at the time and so Teichner and researchers conduct
experiments to make the production of Aerogel more efficient by
experiment and manipulating the chemistry of Aerogel resulting in new
properties.
- 1980's-In the
early 80s particle physics researchers realized that silica aerogels
would be an ideal medium for the production and detection of Cherenkov
radiation. These experiments required large transparent tiles of
silica Aerogel
- 1990's-In 1999 the
space agency fitted its Stardust space probe with a catcher that used
Aerogel to catch the dust from a comet’s tail
- 21st Century-In
2002 Aspen Aerogel, a company created by Nasa, produced a stronger and
more flexible version of the gel that is going to be used in space
exploration.
°•. Thoughts of Samuel S.
Kistler
"Obviously,
if
one wishes to produce an aerogel [Kistler is credited with coining
the term "aerogel"], he must replace the liquid with air by some means
in which the surface of the liquid is never permitted to recede within
the gel. If a liquid is held under pressure always greater than the
vapor pressure, and the temperature is raised, it will be transformed
at the critical temperature into a gas without two phases having been
present at any time." (S. S. Kistler, J. Phys. Chem. 34,
52,
1932).
