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01/23/2001
Lipstick, Warhol and Oxygen Atoms
It isn''t too often that one is concerned about removing lipstick
from a bathtub. You certainly would not guess that someone
working for the National Aeronautics and Space Administration
(NASA) would be approached to handle such a delicate project.
Yet, this is precisely what happened. I''ve often mentioned that I
was employed at the National Advisory Committee for
Aeronautics (NACA), Lewis Flight Propulsion Laboratory in
Cleveland from 1950-1952. This is now NASA''s John Glenn
Research Center. While there I shared a lab with a fellow by the
name of George Fryburg, who was studying oxygen atoms.
George was especially interested in the reaction of oxygen atoms
with metals such as platinum.
The oxygen that we breathe is in the form of oxygen molecules,
which are two oxygen atoms hooked together. Add another
oxygen atom and we have ozone. Split the oxygen molecule
apart and we have oxygen atoms. George''s first problem was to
split normal oxygen and to do this he used what is known as a
Wood''s tube. His Wood''s tube was a piece of glassware
apparatus having a couple of electrodes. Oxygen was fed
through the tube at a low pressure and an electric discharge was
generated between the electrodes by putting several thousand
volts across them. In this discharge, resembling the discharge in
a neon signor lamp, the oxygen molecules pick up enough energy
to split the molecule. The resulting oxygen atoms travel down
the tube where they react with a piece of platinum metal.
Platinum is usually a pretty unreactive metal. However, these
oxygen atoms are anxious to grab onto something and they do,
forming a platinum oxide. The incentive for George to start this
project was the presence of oxygen atoms in a nuclear reactor
environment. I''ve mentioned previously that at NACA we were
supposed to be working on the deservedly ill-fated nuclear
powered airplane.
After I left NACA for Bell Labs, George''s work on oxygen
atoms was revived in connection with NASA''s upcoming space
shuttle. You''ve seen pictures of the fiery reentry of these babies
and at those temperatures there are gobs of oxygen atoms
formed. For the skin of the shuttle, NASA needed to have a
tough material that would stand up to the reentry environment. It
seemed that a logical candidate would be an alloy known to stand
up at high temperatures. What about the nichrome alloy that
we''re all familiar with, the wire used in our toasters? It certainly
gets awfully hot and we know our toasters last many years.
Well, initially, that was just the approach that was considered.
Then someone remembered George''s work on oxygen atoms and
asked him to look into the problem. The nichrome alloy has
chromium in it and the chromium is key to the stability of the
alloy at high temperatures in your toaster. In air, with its 20
percent oxygen as oxygen molecules, the chromium forms an
oxide film that protects the alloy from further oxidation. But
when George turned his oxygen atoms loose on the chromium, it
reacted vigorously even at pretty low temperatures. Chances
were that a nichrome alloy skin would disintegrate on reentry!
So, instead of an alloy, NASA opted for the tedious "pasting" of
ceramic tiles on the outer surface of the space shuttle, an
approach that has worked fine for all these years.
This interest in oxygen atoms at my old stomping ground did not
go away, as I found in an article titled "Rocket Science and Art
Restoration" by Kristin Olson in the January issue of Discover
magazine. Here''s where the lipstick comes in. In another of my
old haunts, Pittsburgh, there was a gala opening of an exhibition
at the Andy Warhol Museum. One of Andy''s paintings,
"Bathtub", is a rather simple black and white painting. To me,
it''s a line drawing of a bathtub with ornate feet on a white
background. The morning after the gala it was discovered that
someone was so enamored with the work that she or he planted a
kiss on said tub! Warhol had not bothered to cover this painting
with the customary protective coat of varnish and the lipstick
posed a very difficult problem for art conservator Ellen Baxter
and her colleague William Real. The red lipstick on the white
background, if treated with conventional solvents, would have
dissolved and wormed its way into the canvas leaving an
unacceptable pink stain.
The problem was so vexing that it was beginning to look like the
bathtub would never again be shown to the public. Frankly, I''m
surprised that some avant-garde artist would not consider
claiming that the lipstick itself, placed in such an unusual
context, was itself a work of art. But then again, I''m not noted
for my expertise in the art world. Enter our white knights from
Cleveland to the rescue in the form of Bruce Banks and Sharon
Miller of NASA Glenn. They had been, knowingly or not,
following in the footsteps of my friend George and his oxygen
atoms.
For NASA, oxygen atoms are still a real pain. Out in space
where shuttles and space stations wander, there happens to be a
fair number of oxygen atoms formed when UV light from the sun
hits and knocks apart oxygen molecules. Without protective
coatings, the polymers used, for example, to hold the solar cell
modules together would be attacked by the oxygen atoms and
our multibillion-dollar effort would go to pot. Banks and Miller
were studying the resistance of various kinds of polymer and
coating materials to attack by oxygen atoms.
One of the current goals in most of today''s government labs is to
interact with universities and other outside entities in developing
other uses for the science and technology coming out of the
government-sponsored research. Banks and Miller''s turn came
when they were contacted by an art conservator, Kenneth Be
(accent over the e) of the Cleveland Museum of Art. Ken was
wanted to clean up some oil paintings covered with thick layers
of soot resulting from a fire in the church where they were hung.
You guessed correctly that Banks and Miller suggested oxygen
atoms. Otherwise, why would I be writing about this? But there
is good chemistry behind it. The soot is sort of mangy, loosely
bound gunk that wouldn''t be averse to pairing up with some
oxygen. The paints underneath, however, are oxides of various
metals and they already have quite their share of oxygen, with no
desire for any more.
Just as you don''t go prescribing a new drug without running
definitive tests first (hopefully), you don''t go blasting oxygen
atoms at a 19th century oil painting without some background
information. You bring in the Cleveland fire department to set
fire to mock living rooms hung with paintings that you wouldn''t
hang in your doghouse. You then take these suitably sooted
paintings into your low-pressure chamber, shoot oxygen atoms at
them and what do you know? All the soot converts to volatile
carbon dioxide, carbon monoxide and water. You also find that a
charcoal marking on the back of one of the paintings is not
affected. Now you''re sure that the only cleaning that occurs will
be where you point the oxygen atoms. If you''re Banks and
Miller you then take a real 19th century painting into your
atmospheric chamber and go to work with your oxygen atoms.
The painting springs to life with more vivid colors and details
than were visible before the fire. The oxygen atoms have
removed not only the soot from the fire but also the other gunk
accumulated over a century or so.
But the conservators in Pittsburgh are an ornery lot. They don''t
trust the Bathtub in the changing pressure and humidity of the
NASA chamber. Also, they want the approach tested on lipstick
itself. So, thinly painted canvases were sent to Cleveland and,
according to the Discover article, interns from the Ohio
Aerospace Institute planted lipstick on the test canvases. I''m not
aware why the interns were chosen or whether they were male or
female. At any rate, the lipstick disappeared like a charm and
Banks and Miller were off to Pittsburgh with a portable oxygen
atom gun.
The gun is sort of neat in that an electric arc (like in George''s
Wood''s tube) forms the oxygen atoms and a stream of inert
helium gas carries the atoms out of the gun to the painting. The
helium keeps the oxygen atoms from reacting with the air en
route. After a day''s work with the gun, Warhol''s bathtub
emerged lipstickless and it is again hanging in the Warhol
Museum. That doesn''t mean that Warhol''s other efforts are
trouble free. At a Warhol exhibit in Vienna, another idiot has
used a felt-tip marker to deface two paintings of Liza Minelli.
One more test to come for the oxygen atoms.
Egyptian tombs provide another venue for Banks and Miller to
test their oxygen gun. The soot from candles serving over the
years to light the way for various archaeologists has darkened the
tomb paintings. And in New York there''s a Monet that was
charred in a fire in a gallery in 1958. My goodness, the
possibilities are boundless. Think of all the soot-covered
buildings and statues that could be cleaned with a really big
oxygen gun!
I thank my friend George for supplying me with details of his
later work. He should be quite proud that his fundamental
studies were the prelude to findings of real practical value both in
space and down here on earth.
Allen F. Bortrum
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