Nanotechnology: the fundamentals
What does it mean to be a billionth of a meter?
Nanotechnology is the study of materials at the subatomic level - materials that are smaller than an atom. A nanometer is one-billionth of a meter. To put things in perspective- if the Earth was 1 meter, a marble next to it would represent 1 nanometer.
Nanotechnology deals with things at the dimension where reality is unlike what we deal with every day, described by classic physics. Materials at this small scale change significantly in regards to their physical and chemical properties. Materials have enhanced properties, such as high strength while being very lightweight. Gravity becomes irrelevant as intermolecular forces become so much stronger. These attributes of nanomaterials come mostly from quantum mechanics, the science of the subatomic level, which explains how nanotechnology works.
Quantum Physics; science that explains nanotechnology
Quantum mechanics is a fundamental theory in physics that describes the interaction and behaviors of subatomic particles. Mechanical, physical, thermal, and catalytic properties are known to change at the scale of fewer than 100 nanometers, known as the ‘quantum realm’, and also because of the increased surface area to volume ratio.
Quantum mechanics is the field of physics that is completely different from Newtonian or classic physics (which describes reality at the macro level). Nanoparticles are also known as quantum dots which observe the reality of quantum physics. Quantum phenomena include superposition (where a quantum entity can be in multiple states simultaneously until observed) and entanglement ( this is when two quantum systems interact or are generated, they become entangled meaning they cannot be described independently). Nanomaterials’ uniqueness can also be attributed to the increased surface area. When an object is cut down into smaller pieces, more sides are exposed increasing the surface area. For nanomaterials, this means increased reactivity because of an increase in active sites.
Wave-particle duality comes into effect as well, which states that subatomic particles (for example, electrons) exist as a wave probability. → An electron can exist anywhere on a wave function, and when that wave function will be observed, it will collapse to show the electron where it probably was.
As the intermolecular forces are so strong, self-assembly also comes into play. Self-assembly is the arrangement of matter due to supramolecular forces that push particles into their rightful place.
Working with things at the Quantum level
For us to work with materials at the Nano level, we need very specialized equipment.
Electron microscopes are used here as electrons are smaller than the wavelength of light used in standard optic microscopes.
Electron microscopes work almost exactly like an optic microscope, except that a beam of highly energized electrons is used to probe and picture a nano specimen. Two main types of electron microscopes are Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM).
Both microscopes consist of an electron emission source, electromagnetic lenses, and an electron detector. Leveraging wave-particle duality, an electron beam is used instead of light, which is accelerated and focused on the specimen through the electromagnetic lens.
In SEM, the electron beam is swept across the surface of the specimen, recording the electrons that bounce back into an image. In TEM, electrons are transmitted through an ultrathin specimen, recording an image based on the interaction of electrons with the specimen. TEMs allows you to capture and explore the interiors of the specimen where SEMs are only limited to the surface. For TEM, the specimen has to be thin enough that electrons pass through it. Sometimes additional tools are required to thin the sample.
Nanotechnology in the real world
Many problems exist at the microscopic level which has been out of reach for humans for quite some time. Not only solving problems, but nanotechnology also opens up opportunities that never existed before. From the lightest, but the strongest thing on earth, graphene, to gold changing its chemical properties we have been taught in high school.
Nanotechnology has the potential to impact every single industry because nanotech’s power lies in changing material structures which can ultimately lead to making or breaking a problem.
Some sectors include:
Electronics
Through nanotechnology, electronics are becoming more capable and efficient. Zinc oxide nanostructures are being used to create LEDs that generate higher light output compared to existing models. Atomically thin indium-tin-oxide (ITO) for touchscreens costs lower to manufacture, consumes less power, and is more flexible. These are only two examples. Electronics are being upgraded through nanotechnology by revamping circuits, transistors, and interconnections as well.
Biomedicine
The most prominent use case of nanotechnology in medicine is drug delivery. An analogy used to describe this is “Cancer is fire. Medicine is the firefighters. But the fire is trying to be extinguished without a fire truck. Nanoparticles are the fire truck providing transportation and protection.” Researchers are working on using nanoparticles to encapsulate and deliver medicine to targeted areas without interfering with healthy cells of the body. Gold nanoparticles are being used to detect biomarkers in the diagnosis of diseases.
Energy
Nanotechnology can tap into areas in the Energy sector where energy is usually wasted or increase the efficiency of tools to capture and store energy. Nanotube sheets to build thermocells that are being used to generate electricity from heat that is usually wasted, like on the sides of a solar cell or a hot pipe. Nanotech solar cells are driving down manufacturing costs easing the shift to solar energy.
Food
Nanotechnology is increasing shelf-life for different food materials through nano biosensors that detect contamination. Carbon nanotubes have shown antibacterial properties that caused Escherichia coli bacteria to die on immediate contact. Nano food packaging improves food safety, identifies if food is contaminated or spoiled, enhances flavors and color quality, and much more.
Limitations for nanotechnology
Some challenges we face with nanotechnologies are mostly centered around how foreign this subject still is. We still don’t know much about quantum mechanics as Richard Feynman said “If you think you understand quantum mechanics, you don’t understand quantum mechanics”. As materials change the properties they are known for, at the nanoscale, we don’t know enough about the change and what will be the consequences of using nanomaterials.
Will the material become more reactive or unreactive? Toxic? Will it be a threat to human genetics?
As we still don’t have answers to most of the questions, it’s not safe to use nanotechnology without proper study and research.
Because of the high surface area to volume ratio, materials at the nano level are known to become very reactive and their catalytic properties increase. Due to their very small size, they pose a threat to pass through cell membranes like crossing the blood-brain barrier. These few reasons are the things we have discovered recently. We have a long way to go fully understand how nanomaterials interact with our body and environment.
Nanotechnology is an incredibly fascinating and promising field with endless applications. Companies like Liquidity, which are using electron-spun Nanofibers to purify water, and Intel which is increasing power, density, and reducing cost per transistor through 14-nanometer transistor technology. This shows how nanotechnology will (and is) play a key role in driving forward 21st-century innovation.
Tl;dr
- Nanotechnology is the field of study of materials at the subatomic scale.
- Because of the small scale, nanomaterials have significantly changed properties attributed to quantum effects, surface area to volume ratio, self-assembly, and increased strength of intermolecular forces.
- Electron microscopes are used to work with nanomaterials. Two main types include Transmission Electron Microscope (TEM), which works with electron beam passing through the specimen, and Scanning Electron Microscope (SEM), which works with electron beam being swept across the surface.
- Nanotechnology has applications in almost every sector like food, electronics, biomedicine, energy, etc.
- Nanotechnology is still a new subject, hence working with it can be a double-edged sword as we aren’t fully aware of what will be the consequences of the change in properties.
