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  • 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!

  • [Theme Music]

  • 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 nanoscaleand 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.

From the size of our airplanes to the height of our skyscrapers, feats of engineering just keep getting bigger and bigger.

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