In the tech space, it feels like we can t go more than 5 minutes these days without hearing someone mentionAI, automation, robots, orvirtual reality. But one of the more unassuming technological developments is certainly nanotechnology. While it s a little more of a silent trend, nanotechnology is set to completely switch up the way we develop and apply technology. Not only in the industry as a whole but in all of our daily lives too. There are a lot of areas wherenanotechis already making a huge impact. But its ubiquity is only set to rapidly increase in the near future. Virtually anywhere we use a product, nanotechnology could play a role. Come with us as we explore exactly what nanotechnology is and how it works, how we re using it today and how we might use it tomorrow.
What is Nanotechnology?
You probably already have a good idea of what technology is. In simple terms, nanotechnology is very similar, just on a much smaller scale. When we re talking about nanotechnology, we re usually talking about the study of these materials, as well as the design and development of nanostructures and devices. The term nano refers to a nanometer scale of generally 1 to 100 nanometers. A nanometer is a tiny unit of measurement. A single nanometer is equivalent to 10-9 meters, or a billionth of a meter. Aside from the implications on economy and efficiency, this minuscule size affords many unique properties to the material that we don t typically see. Nanotechnology represents a fascinating symbiotic relationship between many industries and sciences, including engineering, material science, biology, chemistry and physics. The way these experts come together to develop technology previously unimaginable is almost as intriguing as the materials themselves.
What Are Quantum Effects in Nanotechnology?
Quantum mechanics is concerned with how matter behaves at the atomic level and below. A lot of the time, this behavior is counterintuitive, especially when considering traditional physics. Because nanotechnology works on such a minute scale, we observe someconsiderable quantum effects. Nanomaterials tend to have very high relative reactivity. Even some materials that are unreactive on a larger scale exhibit reactivity on the nanoscale. The considerably higher surface area to volume ratio of nanomaterials gives rise to a greater density of electronic states. This means that reactions on the surface become much more frequent. It s worth noting that the increased reactivity of nanomaterials is also in part to non-quantum factors. This includes the number of reactive sites, functional groups and surface energy, but quantum effects play a huge role.
Quantum confinement is also a significant factor in determining the properties of nanostructures and is at the core of quantum theory. At the atomic and subatomic levels, particles are quantized. This means that they exist in discrete energy levels, rather than in continuous energy bands. As the size changes, so does the gap between the highest occupied and lowest unoccupied energy levels. These are largely responsible for the electronic properties, which we can tune by varying the material s size.
Quantum effects don t only affect the electronic nature of the material, but also its thermal and optical properties. For example, quantum dots are a type of nanoparticle that rely on the quantum confinement effect to perform their functions. As the size of the dots changes, the band gap energy also changes and so do their emitted wavelengths. This tunable optical behavior has many applications but is commonly utilized in the development of lighting devices, imaging, and evenQD-OLED TVs.
What Are the Types of Nanomaterials?
All nanomaterials share the property of having a very high surface area-to-volume ratio. But they can differ a lot in other aspects. At a high level, nanomaterials belong to four groups carbon-based, metal-based, dendrimers and nanocomposites. We re going to briefly cover both of these next.
As you can probably guess, these are made out of carbon and include carbon-based quantum dots and fullerenes. Whereas quantum dots are nanoparticles, fullerenes are carbon-based structures that generally have a diameter of around 1 nanometer.
You can consider all fullerenes as alternative forms of carbon, known as an allotrope. Carbon has many forms, from coal and graphite to the more exquisite and uncommon diamond (yes, your diamond ring and your pencils are made of the same element). Fullerenes, however, are made of almost impossibly thin sheets of graphene carbon, only as thick as an atom. These sheets can form into tubes or spheres, such as the famous buckminsterfullerene, or buckyball. Fullerene spheres are incredibly stable to both pressure and temperature and we ve even seen them in space.
There are various methods for producing fullerenes. But we usually make them either through vaporizing then condensing graphene, extracting them from a solvent, or the decomposition of carbon structures such as hydrocarbons. By adjusting the reaction conditions, such as temperature and the applied voltage, we can control the composition of the produced nanomaterials.
When it comes to metal-based nanomaterials, the most common kinds are quantum dots, i.e. those made of cadmium or lead, and gold nanoparticles. Controlling the size of the quantum dot during production is crucial, so most methods center around optimizing this process. We can make dots by a controlled reaction in a solution or by reacting specific organometallic precursors. However, scientists can achieve finer control over their size and composition through depositing metal ions or atom-thin layers of material onto a substrate.
Gold nanoparticles, on the other hand, can be produced through the reduction of gold ions in specific solutions, growing them from tiny gold particles called seeds, or by depositing gold ions onto the surface of an electrode. As with carbon-based materials, we can meticulously adjust the reaction conditions are to produce the desired size and composition.
Dendrimers take their name from the Greek word for tree. This is because they consist of a core and an outer shell, along with several layers of branched structures. We can create dendrimers either divergently, i.e. from the core outwards, or convergently, i.e. from the outer shell inwards. As with other nanomaterials, we can design their properties with a great degree of precision, such as their solubility, size, and the size of their internal cavity.
Nanocomposites are interesting, in that they re a combination of larger materials with nanomaterials. They re generally one of three types, depending on whether they contain ceramics (nanoceramic matrix composites, or NCMCs,) metals (metal matrix composites, or MMCs), or polymers (polymer matrix composites, or PMCs). The general process for producing any kind of nanocomposite is by choosing the desired base material, dispersing the nanoparticles through the matrix, and then processing the material. They can also be heat-treated following this, depending on the required properties.
Approaches to Producing Nanomaterials
While there are many methods involved in designing and producing nanomaterials, they can all be categorized as either following a bottom-up or top-down approach. The bottom-up approach involves building a larger structure from smaller component parts, such as nanoparticles or atoms. However, the top-down approach refers to miniaturizing a larger structure to the nanoscale, through methods such as lithography, etching or cutting. The table below classifies some of the most commonly used methods according to their approach.
|Method||Used to synthesize||Approach used|
|Molecular beam epitaxy (MBE)||Quantum dots||Bottom-up|
|Turkevich method||Gold nanoparticles||Bottom-up|
|Brust-Schiffrin method||Gold nanoparticles||Bottom-up|
|Organometallic synthesis||Metal nanoparticles||Bottom-up|
|Chemical vapor deposition (CVD)||Carbon nanotubes||Top-down|
|Laser vaporization||Fullerenes, metal nanoparticles||Top-down|
|Arc discharge method||Carbon nanotubes||Top-down|
What Are the Applications of Nanotechnology?
The uses for nanomaterials are vast. For brevity s sake, the main applications are given in the table.
|Fullerenes||Drug delivery, medical diagnosis||The cage structure can trap molecules, making them ideal as chemical tracers (i.e. monitoring pollution), or for drug delivery.|
|Nanotubes||Medical diagnosis, satellite construction, energy storage, water purification||Nanotubes can be combined with biomolecules to detect specific compounds. Modified nanotubes can also remove water pollutants. NASA is even testing them as a means of producing ultra-black colors on satellites to minimize reflection and improve data accuracy. These tubes can also be used to improve the storage capacity of supercapacitors by increasing surface area.|
|Quantum dots||Medical diagnosis, lighting, imaging, solar cells||The tunable nature of dots electronic properties can be used in lighting and TVs, but also in medical imaging. Dots can also help solar cells absorb a wider range of light.|
|Nanoparticles||Scanning Tunneling Microscopy (STM), medical diagnosis, water purification||Electrons in nanostructures can tunnel through energy barriers they normally can t, such as from the tip of a microscope to the sample, to produce a high-resolution image. Gold nanoparticles can also be used to target specific cells. Nanoparticles can purify water too, due to their antimicrobial properties (i.e. silver) or ability to produce reactive oxygen compounds (i.e. titanium).|
|Dendrimers||Drug delivery||Dendrimers have an internal cavity. Scientists are researching how to utilize this for drug delivery.|
|NCMCs||Coating packaging materials||NCMCs increase the heat resistance and flame retardation properties of materials.|
|MMCs||Computer cooling, vehicle construction||MMCs are light and strong, so are ideal for cooling computers and building lightweight vehicles.|
|PMCs||Medical treatments||PMCs are showing promise in growing skin tissue (i.e. for burns) or even organs.|
The Future of Nanotechnology
The ongoing development of nanotechnology is certainly exciting. We re sure to see even more advanced uses for these materials in the future. Drug delivery and medical treatments will become more refined, and medical diagnosis will likely be able to detect anomalies at the subatomic level.Computerswill perform even better, and so will all of the sensors we use in our tech.
There are a lot of potential concerns, however, especially when considering the introduction of nanomaterials into our bodies. Historically, humans have never been exposed to synthetic nanoparticles, so our biology hasn t evolved and adapted to deal with them. While the goal of medical nanotechnology is to reduce the risk of adverse situations such as inflammation and toxicity, this does present a health concern. Of particular concern are free nanoparticles. These are not part of a larger structure and have more opportunity to migrate easily. We can inadvertently inhale these particles, or even absorb them through our skin due to their small size. The health implications of this are largely unknown. So it s imperative that researchers follow strict safety guidelines and exercise caution when handling and developing this technology.
To summarize, nanotechnology is an extremely exciting industry, and nanomaterials are set to become a fixture in our everyday lives. From biosensors and medical treatments to making vehicles and solar cells, and even purifying water, these materials have an incredible number of applications. By controlling the production of nanomaterials at the atomic level, we can fine tune their electronic, optical and physical properties for any situation. While the potential benefits are huge, it s crucial that scientists develop and manage nanotechnology responsibly, to manage the safety concerns.