The human quest for the optimal is insatiable and never-ending. Material scientists are always in search of the thinnest, the strongest, or the most lightweight. In such a quest, a team of researchers from the Laboratory for Theory and Simulation of Materials at EPFL in Lausanne, part of the NCCR MARVEL, have used computational methods to ascertain what could be the thinnest possible metallic wire.
Before delving deeper into their research and its specifics, let’s have a look at the theoretical vision that drove the research.
The Search to Reach the Ultimate Limit in Downscaling
The research focused on one-dimensional materials. It began with the premise that these materials could possess unique electronic properties, citing examples such as carbon nanotubes, ultrathin nanowires, and few-atom atomic chains.
Due to their potential suitability for next-generation applications, researchers grew increasingly curious and eager to explore additional sources for producing these materials.
The researchers identified that exfoliating bulk materials could serve as a natural source for one-dimensional wires. Consequently, they consulted a database of one-dimensional materials that could be exfoliated from experimentally known three-dimensional van der Waals compounds. This exploration ultimately led to the discovery of multiple stable wires.
However, the most significant discovery was locating the thinnest possible exfoliable metallic wire, CuC2. This finding represents a milestone in the scientific community”s quest to reach the ultimate limit of downscaling.
While speaking about the discovery, Chiara Cignarella had the following to say:
“It’s really interesting because you would not expect an actual wire of atoms along a single line to be stable in the metallic phase.”
A significant amount of experimentation was required to reach the metallic wire CuC2, a straight-line chain composed of two carbon atoms and one copper atom—the thinnest possible metallic nanowire stable at 0 K.
The starting point was a collection of more than 780,000 crystals—selected from a range of databases—held together by van der Waals forces. These forces exist as weak interactions between atoms whose electrons are close enough to overlap. The researchers then looked deeper into these materials to find out their spatial organization and assess the energy it would require to separate the one-dimensional structure from the rest of the crystal.
This filtering led to a list of 800 one-dimensional materials, which was then reduced to 14. The researchers finally took this sample of 14 and computed it in greater detail to verify their stability and gauge their electronic behavior.
The final results pointed towards two metals and two semi-metals as the most interesting ones. One among these four was the metallic wire CuC2, a straight-line chain with two carbon atoms and one copper atom. It could be called the thinnest nanowire possible, stable at 0K, and exfoliated from three different parent crystals:
CuC2’s speciality was that it required little energy for extraction and—as a chain—could be bent without altering its metallic properties.
The researchers plan to continue working on their discovery. This process will not only include synthesizing new materials but also investigating these materials’ capability of transporting electric charges and assessing their behaviour at different temperatures.
While this particular research led to a breakthrough, scientific work around nanofibres is nothing new and has been happening for quite some time now. The interest in these metallic wires has been so intense that they have found mentions in popular culture as well.
One of the most well-known mentions of nanofibers has been in 3 Body Problem, the 2024 Sci-Fi series based on Remembrance of Earth’s Past by Liu Cixin. The use of nanofibers in the series and the developments around it in the field of real-world scientific research make us think it is a sci-fi world closer to reality than we think it to be.
Nano Fibers in ‘3 Body Problem’
3 Body Problem utilizes the concepts of Nanotechnology as an integral part of its storytelling. One of the characters in the series, Dr. Auggie Salazar, played by Eiza Gonzalez, is an expert in this field who has revolutionized this domain of study.
The use of Nanofibers, however, is much more than a character-establishing element for Auggie in the series. It is a crucial tool in setting up the biggest and most horrifying set piece of the series. Nanofiber technology is used here as a weapon to preserve technology aboard an enemy ship, the Judgment Day.
The ship has been chartered by reclusive billionaire and alien sympathizer Mike Evans, a character played by Jonathan Pryce. The nanofiber – in this ship – is used as a razor-sharp lattice that ends up killing everyone on board in the most brutal and violent way possible while keeping the Trisolan alien technology salvageable for the humans to take advantage of.
The scene has sparked many speculations around its viability and whether it was feasible for nanofibers to really cut through boats, diamonds, humans, and more.
But what appears to be more important now is the question of how close our technological reality is to science fiction. At least in the case of nanofibers, it is closer than we think. Nanofibers have many real-world applications, and we will explore some of them in the coming segments.
Click here for a list of top nanotechnology stocks.
Nanofibers and Their Real-world Applications
A comprehensive review of nanofibers’ practical application potential shows that they could be used for drug delivery, water filtration, biomedical applications, energy storage, protective clothing, and more.
In the field of healthcare, nanofiber-based wound dressings have proven extremely useful by creating a conducive environment for tissue regeneration. Similarly, in drug delivery, nanofibers effectively release drugs at a controlled rate, enhancing patient compliance and minimizing side effects. Additionally, in medical science, nanofibers support tissue engineering and regenerative medicine, where nanofiber scaffolds can be developed to mimic the extracellular matrix, promoting the growth of functional tissues and organs.
Then, in environmental remediation, nanofiber helps purify water and air. Nanofiber-based membranes can remove pollutants. Additionally, nanofibers help manufacture flexible and stretchable electronic components such as sensors and conductive textiles, contributing to wearable technology and human-machine interfaces.
In the area of advanced tech, nanofibers have the capacity to offer energy storage facilities for advanced batteries and supercapacitors. Their high surface area and porosity make them suitable for such applications. Nanofibers also prove effective for cutting-edge tech applications suitable for use in space explorations, meeting the qualifying property criteria—lightweight yet strong, durable yet safe.
All these application potentials make nanofibers a potent material for tech businesses to work with. Many companies have been working in the field of nanofibers and related development. Below, we discuss a couple of them.
#1. Kato Tech
Kato Tech stands ahead of many of its peers in the domain because of the sheer efficiency it has introduced to the nanofiber manufacturing system. The company’s Nanofiber Electrospinning Unit uses electrospinning techniques to safely and easily produce nanofibers with diameters of 50 to 800 nm. The Kato Tech device is capable of producing nanofibers even from a small amount of diverse polymers.
While elaborating on why Kato Tech’s deployment is a breakthrough for the nanofiber industry, Yoshihiro Yamashita, Professor at the Research Center for Fibers and Materials, University of Fukui, said:
“Kato Tech Co., Ltd. in Japan undertook the development of an electrospinning device for lab use and created a system that included a voltage generator and nozzle, roller movement, a quantitative syringe pump, and a draft function. This device largely featured the ideas of Drexel University’s Dr. Frank Ko, a leading authority on electrospinning, and made it possible to create nanofibers easily using electrospinning.”
The device has a pointed positive electrode (capillary) and a flat negative (ground) electrode. When high voltage is applied between the two electrodes, it attracts the charged molten polymer or polymer solution from the capillary through the electric field toward the negative electrode. As a result, the low molecular cohesion polymers become a spray, and the high molecular cohesion ones further separate into fibers, get attracted to the negative electrode, and form a thin layer of fibers again.
According to its latest available financial reports, Kato Tech earned 29,568 million yen in the first six months ended on September 30, 2022, registering an annual growth of 13%.
#2. American Elements
Another company that has been doing comprehensive workaround nanotechnology is American Elements. Its products span the domains of nanoparticles and nanopowders, nanoparticle dispersions, functionalized nanomaterials, carbon-based nanomaterials, and nanotechnology-powered inks, prisms, rods, spheres, tubes, wires, and more.
If we only look into the company’s nanowire capabilities, we will see that it has nanowires made of aluminum, gold, silicon, iridium, cobalt, iron, silver, copper, lead, manganese, nickel, and many more.
If we talk about nanofibers in particular, the company offers carbon and silicon nitride nanofibers. Its carbon nanofibres are tubular, high-surface-area carbon nanostructures with applications in alternative energy, electronics, and medicine, whereas its Silicon Nitride nanofibers prove effective in food, agriculture, pharmaceutical, and optical solutions.
American Elements claims to be the world’s largest manufacturer of engineered and advanced materials. It provides both technical guidance and manufactured products in an over 12,000-page online catalog that includes over 3,000 elemental metal, chemical, ceramic, and crystalline stock items.
The Nanofiber-Powered Future
Nanofiber-related developments will soon become visible across the world. One country that has been making outstanding progress in this field is Japan. According to data provided by MECC Nanofiber, the number of articles related to nanofibers exceeds 40,000 in Japan as of March 27, 2024.
Nanofiber has already demonstrated its commercial viability by enabling high-performance products such as filters and face masks. These products benefit from nanofibers’ high dust collection efficiency and low-pressure loss.
Nanofibers offer significant advantages in the biomedical, med-tech, and healthcare sectors due to their versatile properties that make them medically useful. For instance, they are excellent materials for building cell proliferation scaffolds because they adhere easily to cells. They go beyond being merely biodegradable; they are bioabsorbable, safely decomposing in the body over time. Due to their porosity and vast surface area, with small gaps that allow solutions to penetrate, nanofibers exhibit excellent moisture retention, physical and dynamic strength, and adjustable elasticity.
We have already discussed the material’s many medical application benefits. In the future, nanofibres will also see increased adoption as transdermal absorbents, drug-release artificial skin, artificial blood vessels, corneas, and skin, and even filling agents for artificial bones.
Moreover, each day brings us closer to the disturbing scenarios depicted in ‘3-Body Problem’, highlighting the growing importance of research and development in nanotechnology and nanofibers. This research is crucial as it helps regenerative healthcare advance in increasingly complex scenarios, serving as just one example of its many potential applications.
Click here for a list of five companies leading the development of nanotechnology.
