An Introduction to Nanotechnology

Figure 1 example concept of nanobot designed to deliver payloads to malicious cells/microorganisms.
Figure 1 example concept of nanobot designed to deliver payloads to malicious cells/microorganisms.

Although nanotechnology may bring to mind thoughts of advanced sciences and applications in technology, this field of study doesn’t have to involve technology whatsoever! Nanotechnology is an umbrella term that encompasses any and everything that exists in the scope of 1-100nm, hence “nano”technology.

Such studies might seem a bit unrelatable to some of you, but nanotechnology is actually present in every aspect of our lives. Whether it be from toothpaste to cosmetics, to sunblock and our electronics, the use of nanotechnology is present in near all aspects of our daily lives.

Nanotechnology in Other Fields

Figure 2 ”inverse fingerprint” developed through use of gold/silver nanoparticles
Figure 2 ”inverse fingerprint”

developed through use of

gold/silver nanoparticles

You probably already guessed that nanotechnology is the subject of much scientific and medicinal research. Obviously, the results of such research would be directly applied to fields like biomedical engineering, but think for a second. What other fields might the broad scope of nanotechnology be applied in? Did you ever imagine that such sciences are crucial in solving crime cases?

Imagine you are a detective, sent out to investigate a death reported by the neighbors of the victim. As you enter the scene your nose is assaulted by the scent of blood. A pair of shoes lies messily underneath an unmade bed, and you can see clothes strewn about all over. On the desk lies a saddening suicide note. In the middle of the floor, lying in a pool of blood lays your victim with a gun in hand. Upon closer inspection you notice faint traces of footprints on the floor. A case of suicide, or is it?

As you dust for fingerprints you realize that they aren’t showing very clearly on the suicide note. Luckily for you, a method was developed to find “inverse fingerprints” through the use of gold and silver nanoparticles.

Some quick analysis shows the “whorl” of the fingerprints on the paper pointed towards the left, indicative of the left hand, but the victim was right-handed! Furthermore, fingerprints not belonging to the victim were also found on the paper.

Remembering the faint footprints, you use the same method to examine the design of the sole of the shoe. Interestingly enough, you find that the pattern does not match any of the shoes owned by the victim. Was a third party involved here? Taking the suicide note and all available writing utensils with you, you hurry back to the lab to perform some material analysis.

Figure 3 examples of nanoparticles of different pigments in ink
Figure 3 examples of nanoparticles of different pigments in ink

Many pen manufacturers use ink containing nano-sized particles, which vary from brand to brand.

After some analysis you find that the nanoparticles of the ink the letter match none of the pens found on the victim’s desk. Keeping in mind that a stranger’s fingerprints were also found on the paper… the letter was forged! A premeditated homicide by the looks of it. And you were able to deduce all of this, much more than meets the naked and microscopic eye, all with nanotechnology.

Nanotechnology’s Relation with Thermodynamics

Not only is nanotechnology applicable to real life situations, but it’s also related to what is taught in a chemistry class. The second law of thermodynamics essentially states that entropy of an isolated system never decreases, but an interesting discovery through the use of nanotechnology falsified this universally held physical quantity.

Chemical physicists in Australia measured changes in the entropy of latex beads, each a few micrometres across and suspended in water. By using a precise laser beam to trap the beads, they were able to measure the movement of the beads and calculate the entropy of the system at short time intervals. They discovered that the change in entropy was negative over time intervals of a few tenths of a second, disproving the second law of thermodynamics, but over time intervals of more than two seconds, an overall positive entropy change was measured and thus normality was restored.

Figure 4 examples of latex beads
Figure 4 examples of latex beads

This discovery is interesting in that it introduces a sense of randomization of the increase in concentration of energy in the system. This means that nanocircuits can potentially heat up spontaneously and then shortly afterwards return back to their normal temperatures. If this energy can somehow be harnessed, our issue of using fossil fuels as our current main fuel source won’t be as detrimental if we can absorb energy right out of the air. It can be concluded that the second law of thermodynamics is violated at certain time and length scales which may lead to new interesting discoveries about the laws of thermodynamics and maybe even an alternative power source.

Nanotechnology and Electrical Energy

Figure 5 Li2O2 crystals that form on bare carbon nanotube (left), and carbon nanotubes with RuO2 (right). Top: schematic views. Bottom: transmission electron microscopy images.
Figure 5 Li2O2 crystals that form on bare carbon nanotube (left), and carbon

nanotubes with RuO2 (right). Top: schematic views. Bottom: transmission

electron microscopy images.

Compared to advancements made in processing powers, also made possible by nanotechnology, batteries have not seen many improvements in the recent boom in mobile technology. This is so because in order to amplify the performance of these processors, all that has to be done is make the size of each individual transistor (measured in nm) smaller. If they are made smaller, then the switches inside can be turned on/off much faster since the electrons that do the processing has to travel across smaller distances. Batteries, however, are more complicated than just changing their sizes. Recently, it has been found that ruthenium oxide (RuO2) nanoparticles can be used to significantly enhance the recharge efficiency of non-aqueous lithium-oxygen (Li-O2). Compared to conventional batteries, Li-O2 batteries let lithium directly react with atmospheric oxygen. When the battery starts discharging to power the device, Li2O2 crystals are formed, but to recharge the battery, these crystals must be decomposed, a reaction which can shorten battery life. Byon and Yilmaz, two scientists working to improve the battery recharge efficiency, found that by adding RuO2 to carbon nanotube cathodes where lithium and oxygen react, the battery recharge potential was considerably lowered. Tests using x-ray absorption spectroscopy and electron microscopy revealed that these Li2O2 particles that were formed on RuO2 nanotubes made itself into a formless layer, rather than a conventional morphology of halo-shaped crystals.The team noted that the new formless layer has a large contact area with the conducting nanotube cathode, and that Li2O2 could decompose with less energy, thus improving the battery efficiency.

This whole phenomenon is made possible because the RuO2 synthesized nanotube revealed to have nebulous morphology at the nano level. Manipulation of the structure of these nanostructures can lead to different properties such as having higher contact area or decomposing with less energy required.

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