Key Terms
Atomic Force Microscope (AFM)
Buckyballs (Buckminsterfullerene)
CRISPR
nanometer
nanotubes
Introduction
A nanometer is a very small unit of distance. 1 nanometer (nm) is one billionth of a meter. Put another way, the diameter of a human hair is about 50,000 nanometers. We are talking atomic dimensions here. Any technology that works in the range of few hundreds of nanometers to less than one nanometer is called nanotechnology. It covers a very wide range of applications that deals mainly with material engineering, communications and/or data transfer, chemical engineering, and computer applications.
As a young student, I was taught that you could take a substance (gold, for example) and keep dividing it half ...over and over again and it would still be gold. That is, until you get to the individual atom. After that, any further dividing and you no longer retain the properties of gold. It was stated (by definition) that the atom was the smallest unit of an element that would retain all the properties of that element. That is not entirely true. The behavior and properties of a substance on the nanoscopic scale may be entirely different from properties we see on the macro scale.
Example #1: Life in the nanoworld would seem very strange to us. Our motions are controlled by gravity and inertia. We are pulled to the ground by our weight, and if we want to move, we only have to worry about friction and inertia. On the small scale, we would be strongly influenced by what we happen to be close to (other atoms). Can you imagine walking next to your refrigerator and it produces strong forces on you (the closer you get) which influence your ability to move? You might not be able to move at all if you got too close to the TV. Atoms are influenced by molecular forces (gravity and inertia are negligible).
Example #2: Wood is flammable, but not explosive. However, if you grind wood down into a very fine powder, it can be highly explosive in air. The reason has to do with the difference in surface area. As a fine powder, there is immediate access to oxygen, which produces a dramatic change in the properties of the material. The same can be said of most substances. Gold, for example, is actually red in color if reduced to a fine powder. Mineralogists realize that the streak (color of a mineral in fine powder form) is often much different from the color of a large sample of the same mineral. On the nano scale, a substance's melting point, optical properties, electrical properties, density and tensile strength can all change.
Example #3: Have you ever watched water "bead up" when it spills on a table? Water molecules form drops because of an attraction between like molecules (called cohesion). This attraction causes strange effects at the surface of a liquid. It seems like the liquid develops a "skin" which we call surface tension. This effect is noticeable, but not highly significant on the macro-scale. However, as the liquid droplets get smaller and smaller, this effect becomes greater and greater. At the nano-scale, liquid drops behave like steel balls.
Example #4: How would you like living in a perpetual earthquake? That is exactly the situation on the atomic scale. Atoms are constantly in motion so the exact position of atoms is difficult (in fact, impossible) to pin down at any one time.
Example #5: The behavior of matter on the quantum level (size of atoms) can often defy our macroscopic notion of common sense. You would freak if you suddenly observed your hand mysteriously move through a wall, or a basketball suddenly teleports across the room (like on Star Trek). Oddly enough, these things actually do happen on the atomic scale thanks to quantum effects.
The bizarre micro world! (animation)
The macro-world is very different from the nano-world. Engineers are seeing the nano-world as a playground to realize ideas that were science fiction just decades ago. However, the strange behaviors of matter on this scale pose great challenges to engineers and scientists. It also defies the standard paradigm in the way things are manufactured. The standard methodology is to take something big and find ways of making it smaller. This is certainly the case in electronics if we look at the way standard circuit boards are manufactured. Nanotechnology, however, builds things up from the ground level ... atom by atom. This approach requires engineers to "think outside the box" because matter behaves much differently on this scale. We are actually just opening the doors on this new technology. New ideas are growing like weeds. Who knows where it will lead us?
In 1959, Richard Feynman ushered in the idea of nanotechnology when he delivered a lecture to a group of engineers. The title of the lecture was There is Plenty of Room at the Bottom. If interested, read the transcript at link 6.5.a. His ideas were probably very radical at that time.
In 1985 scientists manufactured a new form of carbon - the Buckyball. It is basically a molecular soccer ball consisting of 60 carbon atoms. The name, Buckyball, came from the architect Buckminster Fuller who designed the geodesic dome (the shape of this molecule). The name has evolved to Buckminsterfullerene. They were found in carbon soot by depriving a combustion process enough oxygen to complete the burn. Buckyballs are more than a curiosity. They have been used as n-type layers in photovoltaic cells to boost the efficiency by 300%.
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Courtesy Wikimedia Commons |
Courtesy Wikimedia Commons |
C60 - Buckyball
The next advancement was the creation of nanotubes in 1991. Here chains of hexagonally arranged carbon atoms were formed into the shape of a tube.
Carbon nanotube (animation)
Courtesy
Wikimedia Commons
Nanotubes have many applications based on their physical properties. They are ten times stronger than steel so materials engineers see many possibilities for these fibers. For example, plastics embedded with carbon nanotubes could make lighter airplanes, tougher tanks, safer spaceships, and disposable automobile fenders. They conduct electricity better than copper (with 1/6 the weight) so electrical engineers envision the wires of the future. Nanotubes can be made into semiconductors so they may be at the heart of computers in the future. They have excellent heat conducting properties with no adverse thermal expansion. Nanotubes have the ability to hold an electrostatic charge which makes them stick to surfaces better. Add some nanotubes to paint and you may never have to paint something twice. Nanotubes may help us gain our independence from fossil fuels. TiO2 nanotubes have been used with sunlight to efficiently split water molecules (hydrolysis) for the production of hydrogen gas (a combustible gas). These same tubes may also be used to store the hydrogen gas once it has been isolated. Nanotubes are the future!
The Atomic Force Microscope (AFM) made nanotechnology possible. You can't manipulate atoms if you can't see them. The way this microscope works is similar to the way ants map their world with their antennae. However, the antenna this microscope uses isn't necessarily responsive to physical touch, but rather to molecular forces. Remember, in the nanoworld molecular forces rule!
A very thin carbon nanotube acts as the antenna (tip) which moves over the surface to be scanned. This tip can make physical contact with the atoms on the surface or move in response to molecular forces acting on it. A laser tracks the deflection of the tip and a computer interprets these deflections to an image.
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AFM image of single polymer chains |
Atomic Force Microscope |
The Atomic Force Microscope was invented in 1986 and offers resolution down to the fraction of a nanometer. There are other types of microscopes on the market, but this one opened the floodgates.
Chemists have been manipulating atoms for centuries. The difference, now, is engineers can manipulate individual atoms. Scientists have found that the same carbon nanotube tip that is used in the atomic force microscope (see above) can also be used to re-arrange individual atoms. Another device to move atoms is the optical tweezers (the pressure of light exerts forces to manipulate atoms). Engineers have come up with a plethora of techniques to synthesize and move nanoparticles. The details are beyond the scope of this course.
Nanotechnology has an almost limitless future in terms of applications.
However, current research has concentrated advancements in four general
categories:
Material Designs
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Smart Yarn?
Using a forest of nanotubes, researchers have spun fibers which are light weight and are bullet proof. |
| Keep it cool Integrated circuits produce heat as a result of electrical resistance. To help cool your PC researchers have created heat sinks using carbon nanotubes. Tests have shown that the nanotube cooler worked as well as copper heat sinks (one of the best materials to use as a heat sink). However, the nanotube coolers are smaller, lighter, and less expensive than copper heat sinks. This is also important for applications such as cell phones, digital audio players, and personal digital assistants. |
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Don't get burned on your next vacation! |
| Clean water anyone? Researchers have constructed a water filter that filters 99.9999+% of all viruses and some of the smallest of particles. This could be extremely useful for third world countries that desperately need a source of clean water. |
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Remove contaminants in groundwater with iron nanoparticles Studies have shown that iron has the ability to neutralize toxins in water. Injecting iron nanoparticles into a well has shown to be an effective way of cleaning polluted areas. This can be a lot easier than pumping the water, treating it, and reintroducing it back into the ground. |
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Nano shades Nanotechnology is used to produce a UV protective and antireflective ultra-thin polymer coating for sunglasses. It also gives the glasses scratch resistance as a bonus. |
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Digest This Idea! Nanotechnology can be used in preserving our food! Clay nanocomposites can be used to create a protective layer around packaging mediums. This protective barrier restricts the gasses that cause food to spoil such as oxygen and carbon. Ultimately this could preserve food for longer without the use of preservatives, nitrates, and nitrites. |
| Keep the bugs from your grub Nanotechnology can be used in packaging foods. There is a nano-composite coating that places anti-microbial agents on the surface of the coated film that is used in food packaging. It is not only used with how the foods are being packaged, but it is also used in how they are being produced and processed. |
| Nanotechnology in the Tour De France A Swiss manufacturer of bicycles is producing a bicycle that is said to weigh less than 1 kg. This bike called the "Pro Machine" uses carbon nanotubes to reinforce the spaces between carbon fibers. |
| Want to win Wimbledon? Get double the life of the bounce of your tennis ball? Wilson's double core tennis balls consist of a butyl rubber and nanoclay particles which, when mixed together form a coating which bounce for twice as long as the traditional tennis ball. |
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Self Cleaning Windows? Why does water roll off certain leafs? The leaf repels water because of tiny bumps on the surface which did not allow water molecules to come in close contact. Using nanotechnology, the same thing could be applied to glass so that water would roll off like water rolls off a duck (or leaf). |
Electronics
| Throw away your hard drive? There is a company that has copyrighted a technology using nano technology for data storage. This is similar to holographic drives. This storage device uses 3.5 inch disks and will store between 10 Terabytes and 100 Terabytes. The whole idea is based on the fact that it is possible to change (and maintain) the state of a molecule with light and electric fields. The state of the molecule is like a switch. This way, the state of molecule can hold information such as a binary (0) or (1). |
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Quantum dots can light up your life?
Quantum dots are semiconductor nanocrystals. They can absorb and release discrete amounts of energy. The smaller they are, the more towards the blue end of the spectrum they work. So what could they be used for? For one, color! Maybe some day quantum dots will be at the heart of all LED's making the incandescent light bulb obsolete. |
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Nanotube radio?
Alex Zettl has come up with a nanoscale radio where the key circuitry consists of a single carbon nanotube. The nano-radio is able to convert electromagnetic oscillations of a radio wave into mechanical vibrations. These nanotube vibrations are converted into electrical pulses that reproduce the original radio signal. |
Healthcare and Biotech
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Fight cancer with nanoprobes? Breakthroughs in medicine have been able to manufacture antibodies capable of targeting cancer and other disease directly. The body's immune system tends to fight even antibodies which are supposed to be helping the body. Medicine can be administered with a specific target and dosage to effectively attack things such as breast cancer. These nano-particles may be the best hope for curing once untreatable diseases. |
I would like to add a few comments to
this student's report. Cancer has many forms and some have markers to
which antibodies have been designed (and hopefully will be for other types of
cancer). Once a marker has been found (or other means to target the cell),
a gold nanoparticle can be attached to it (like hitchhiking). Once the
gold is in the cancerous cell, the body is radiated with specific frequencies of
electromagnetic waves that the gold will absorb. This heats the area and
destroys the tumor, leaving the adjacent healthy tissue unharmed.
Source: Nanotechnology Demystified ISBN -13: 978-0-07-146023-1 pp:97-99
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Surgeons Best Friend? Since as much as 50% of a surgeons time is spent trying to stop bleeding, the news of a liquid nano-gel that stops bleeding in 15 seconds has to be big news. In fact, there is no need to remove the gel since the body breaks it down naturally. This has to offer great benefits to the military and EMTs as well. |
Energy
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Nanotechnology to make fuel cells viable? Nanotechnology shows promise in several areas of fuel cell development. First, platinum is typically used as a catalyst in standard fuel cells. That is, it speeds up chemical reactions. Since platinum is expensive, nanoparticles not only do the job better but cheaper as well. Second, the proton exchange membrane can be constructed with nano-filters. Third, the electrodes (and even the electrolyte) have used nanoparticles in their makeup. Finally the hydrogen that is needed for the reaction to occur can be safely stored in nanotubes and released as needed. Maybe all these things will produce cheaper, more efficient fuel cells. |
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Toss those AAA batteries away? Joel Schindall of MIT is working on a capacitor that may replace batteries. Using carbon nanotubes, Schindall has created capacitors with a very large area and a very small separation giving them the ability to hold a lot of energy. Maybe the best part is that his capacitor is able to be recharged in minutes or seconds and is 100% reusable. |
CRISPR Technology
This technology is so new (it was first demonstrated in 2007), no one knew exactly how it worked in 2017. It is so new I really didn't know where to put it in this course, so it ended up here. Actually the technology is known as CRISPR-Cas9 and is a way of snipping (and editing) sections of DNA. Of course, DNA is the very long chain of genetic code that defines all organic life on Earth. Human DNA consists of about 3 billion base pairs (a string of 3 billion molecules wrapped around another string in a double helix shape). All the genetic information to make YOU is in each of the nuclei of every one of the 37 trillion cells in your body. Without turning you into a biologist, all you need to know is that nature always attempts to create exact duplicates of DNA when a cell divides but nature also isn't perfect at that. When there are change in the genetic code, there are often changes in the results (we simply do not know what every part of the DNA code does). Some genetic changes are advantageous to a life form, and others are not. Nature has been doing this for billions of years to produce the wide variety of life we now find on our planet. Have humans gotten into this game? You bet! Perhaps you have heard of genetically altered food? Here, biologists selectively breed out bad traits and enhance traits that produce a better yield or taste. Every day you eat food that has been altered to resist drought, grow better in different climates, taste better, etc. This has been going on for a very long time. What is new is biologist have taken an idea found in bacteria and use it as a tool to produce genetic changes. Here is how CRISPR got discovered. Certain bacteria can fend off invaders by snipping the attacker's DNA, essentially neutralizing the invader. Biologists took that idea and can now slice the DNA of any life form. The possibilities, dangers, and ethical concerns now seem endless. It is much too early to see where this will all lead but one can imagine ways to fight off the common cold, fix genetic disorders (sickle cell, downs syndrome, etc), cure Alzheimer's, and other degenerative diseases like ALS. Wow!
©2001, 2004, 2007, 2009, 2016, 2019 by Jim Mihal - All rights reserved
No portion may be distributed without the expressed written permission of the author
