Instant
Waterproofing (4.10.03) - What if you could instantly transform your coat
into a raincoat whenever you need one? Scientists have just made the very
first switchable surface.
Waterproof
and Germ Proof (8.28.03) - Nanotechnologists are making lightweight fabric
that’s waterproof and germ proof.
When you pick out presents for the kids this year, wouldn't it be great to
give them clothes they couldn't mess up, no matter how hard they tried? As
this ScienCentral News video reports, thanks to nanotechnology new fabric
for kids' wear can actually repel spills.
No More Greasy Kid Stuff
Kids and messes usually go hand in hand. But what if their clothes refused
to let stains soak in?
Chemical engineer and entrepreneur David Soane may be making this a reality.
In 1998, he left the University of California, Berkeley to start Nano-Tex,
where he uses the principles of nanotechnology to improve the strength and
durability of natural fibers like cotton. His breakthrough was to create tiny
structures that he calls "nanowhiskers," tiny hairs that make liquid
spills bead up and roll right off fabric.
Soane found his inspiration for nanowhiskers by washing a familiar fuzzy fruit.
"When you wash a peach, very often the water rolls right off," explains
Soane. "That's because on the fruit's surface, there are all these little
pointed whiskers." The nanowhiskers can repel stains because they form
a cushion of air around each cotton fiber. When something is spilled on the
surface of the fabric, "the miniature whiskers actually cohesively prop
up the liquid drops, allowing the liquid drops to roll off," says Soane,
who calls his stain-proofing process Nano-Care.
Each of Soane's synthetic nanowhiskers is only ten
nanometers long (a nanometer is only three to five atoms wide), made of a
few atoms of carbon. "They repel a range of fluids," says Soane,
"including coffee, tea, salad oil, ketchup, soy sauce, cranberry juice.
The nanowhiskers are intentionally designed to be flexible." To attach
the nanowhiskers to cotton molecules, Soane immerses cotton in a tank of water
full of billions of his tiny structures. "They look like miniature pill
bugs in water," Soane explains. "The pill bugs roll up into little
balls, with the little whiskers pointing inward," towards the fabric’s
fibers.
Soane's next step is to heat the soaking fabric, causing the water to evaporate.
As it does the tiny nanowhiskers form a permanent chemical bond with the cylindrical
cotton fibers, which compared to the nanowhiskers, are the size of tree trunks.
Once the whiskers attach themselves, the fabric changes permanently, so the
whiskers can't wash or wear off. The result is stain repellant cotton that
looks and feels just like the ordinary fabric, not stiff or fuzzy, like other
stain-proofing processes, which merely coat fabrics. "The fabric stays
soft because this layer of whiskers is virtually invisible, compared to the
size of the fiber," explains Soane. "You can't touch or feel the
presence of this layer."
Soane is also working
onNano-Touch,
a process that makes wool and cotton more durable, and Nano-Dry,
a means of wicking away sweat and keeping clothing free of body odor, that
is already available in some sportswear.
Soane's nanowhiskers are already available in jeans and khakis, including children’s
sizes. He says his cotton could be made into more clothing for children by
next year.
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