From the size of our airplanes to the height
of our skyscrapers, feats of engineering just
keep getting bigger and bigger.
But bigger isn’t always better.
Sometimes you want things to be small.
Really small.
And if you want things to be really small,
you’re gonna need to make them out of small
materials: nanomaterials.
These are used everywhere from the healthcare
industry to electronics.
And, even though they’re small in size,
they pack a big punch!
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It’s easy to think of big problems,
ones that you can see.
But many of today’s most important problems
are actually microscopic.
Think of things like cancer or autoimmune
diseases.
These are issues at the cellular level, far
too small to solve with any conventional tools.
And even if we find a solution to the root problem,
the body's own defense mechanisms will often see
a potential cure as a threat and attack it.
A good example of this is Type I diabetes,
a chronic condition that requires treatment
with insulin.
To permanently fix the problem, doctors
might want to implant cells to produce that
insulin without needing daily injections.
But if you just stick those cells right into the human
body, the patient’s own antibodies will probably
attack and kill them before they can help.
So for this potential treatment to work, you
need to find a way to protect them.
To solve this problem, and others like it,
you’re going to need to build really small
things.
And for that, you’ll need nanomaterials.
For something to officially be a nanomaterial,
at least one of its dimensions must be smaller
than 100 nanometers.
To put that in perspective, a nanometer is one
millionth of a millimeter, or about 100,000 times
smaller than the diameter of a human hair.
So pretty tiny!
In fact, most nanoscale materials are too small to be
seen even with the help of conventional microscopes,
like the ones you might find
at your high school or college.
If you want to take a look at nanomaterials,
you’ll have to use a better microscope,
like an electron microscope, some of which
can magnify samples by up to 1 million times.
Even then, to actually work on the nanoscale,
you need something like the scanning tunnelling
microscope,
which not only allows you to see individual atoms
and molecules, but also lets you move them around.
But don’t let the small size of nanomaterials
fool you.
Compared to their larger-scale counterparts, they
often have better properties like increased strength,
chemical reactivity, and conductivity.
These traits can let you solve new kinds of
problems, like protecting those implanted 
insulin-producing cells I mentioned earlier.
The device you’ll need to protect those
cells will have to have holes large enough
to let the insulin flow out,
but small enough to keep the body’s attack
cells from getting in.
That kind of precision engineering is a perfect
application of nanotechnology.
While nanomaterials are certainly small, they
actually have a comparatively large surface area.
That may sound a bit counterintuitive, but if
you break something down into smaller chunks,
the overall surface area increases.
You can see what I mean if you take a block
and slice it down the middle.
You didn’t change the overall mass or amount
of material, but now you have two new sides
that add more surface area.
The more surface area there is, the more direct
contact a material can have with its surroundings,
and that contact matters!
For example, break a material into nanometer-sized
particles, and the increased surface area will lead
to a faster rate of any surface-level reactions.
This makes nanomaterials great catalysts,
or substances that increase the rate of a
chemical reaction,
and it’s why they’re used in a wide range of
important industrial chemical reactions.
Nanomaterials are also often more attractive
to water and oil molecules, making them more
absorbent than larger materials.
That’s why they’re used in water treatment
plants to remove pollutants and at sea to
clean up oil spills.
We’ve also found that solid nanoparticles
can even act like liquids –
not just as some sort of bulk movement, like you
might see when a pile of sand acts like a fluid, but
in the motion of individual particles themselves.
On their outermost layers, only about an
atom or two thick, these nanoparticles appear
to move about like a liquid.
Even though their insides are solid, their
outsides can change shape and wobble about
like a drop of water!
If you want to form solid, stable shapes out of
nanoparticles, these movements could potentially
cause your designs to fail, like losing an electrical
connection in a circuit.
The nanoscale will even change other properties
of a material, like its melting point and fluorescence,
or the visible light that it emits.
Basically, its color.
A great example of this is gold.
Instead of the color we’re used to seeing
in a treasure chest, nanoscale gold can appear
red or purple.
This unique visual property might one day
lead to better imaging and detection of things
like tumors.
In these ways, it’s possible to literally fine-tune
some of the properties that you’re interested in
just by changing the size of a material.
By taking advantage of these characteristics
and making your own nanomaterials,
you’ll create what we call engineered
nanomaterials, ones that are designed and
produced to help solve problems.
There are also naturally occuring nanomaterials,
like volcanic ash or soot from a fire,
as well as ones that are produced as by-products
of other processes like combustion.
These are often termed ultrafine particles and
aren’t really what you’ll be worried about as an engineer.
However, you might have to factor in the effects
of any ultrafine particles that you accidentally make.
But it’s the engineered materials that you’ll
work with that show great potential for medicine,
electronics, and other fields.
The nanotechnology you can make with nanomaterials
can be used to design medicine that will target specific
cells or parts of the body.
Think of the potential in not only helping out your
own cells or keeping implanted ones safe, but in
fighting off things like cancer or harmful bacteria.
And the small size of nanomaterials makes
them perfect for electronics.
If you’ve ever looked at a circuit board,
taken apart your smartphone, or put together
your own computer,
you can see just how small
some of their components can be.
In fact, the semiconductors in computers are
often on the nanoscale – and soon some may
have parts only a nanometer long!
With electronics only getting smaller and smaller,
we’ll likely see nanomaterials playing bigger and
bigger roles in our tech-based future.
And hand-in-hand with modern electronics are
batteries.
The strength and conductive properties of
nanomaterials make them perfect for energy storage
and creating high-capacity batteries.
You know, so your phone actually lasts through
the day.
Nanomaterials can even be added to other materials,
like cement or cloth, to make them stronger and lighter.
Thousands of common products contain engineered
nanomaterials, while many others are manufactured
using tools built from them.
Think of sunscreens, cosmetics, tires, and
many sporting goods.
One of the most prominent areas of nanomaterial
research is carbon nanotubes.
Efforts are being made to use this tube-shaped material
for cleaning up oil spills, making better capacitors for
circuits, and even creating artificial muscles.
But while nanomaterials seem great, there’s
one pretty big problem:
we don’t have a complete sense of the potential
effects that they might have on the human body
or the environment.
That means that we don’t know all of the
safety risks and what the proper protocols
should be when dealing with them.
And there have already been problems with
nano-sized particles.
It’s easy to ingest or breathe in such small
things by accident and without even noticing.
For example, we’ve seen that some kinds of
carbon nanomaterials can cause inflammation in
the lungs in ways that are similar to asbestos.
If you’re using nanomaterials to treat a
disease, the last thing you want is to create
new, unexpected problems.
Fear of the unknown isn’t a good reason
to stop moving forward, but more research
is always better.
The nanotechnology that could keep implanted
cells safe inside your body to treat diabetes is still
pretty new and in the development stage,
but what it could do for patients would
be life-changing.
Similar designs could be applied to other
diseases, giving us effective cures to many of
the problems that millions face every day.
From healthcare, to carbon nanotubes, to
making better batteries, the possibilities of what we
can do with nanomaterials seem endless.
Today we learned about nanomaterials, how
small they are, and some of the things that
they can do.
We learned about the special properties of
nanomaterials and how some of them can change
at different sizes.
Then we found the difference between engineered
nanomaterials and ones that occur naturally.
Finally, we saw that since nanomaterials and nanotechnology are so new to us, we still need further research to fully figure out just how safe they are to use.
I’ll see you in our next episode, when we’ll
learn more about biomaterials.
Crash Course Engineering is produced in association
with PBS Digital Studios.
If you want to keep exploring big scientific
mysteries by going very, VERY small,
Deep Look is a 4K series that aims to see the unseen
at the very edge of our visible world, from eye popping
mantis shrimp to blood sucking mosquitos.
Check out Deep Look a the link in the description.
Crash Course is a Complexly production and this
episode was filmed in the Doctor Cheryl C. Kinney
Studio with the help of these wonderful people.
And our amazing graphics team is Thought Cafe.
