What are Nanomaterials and How are They Made?

Nanomaterials are small — very small. These materials are so small that the unaided eye can’t see them, and manufacturers need specialized equipment to create them. Despite their size, they are having a big impact on manufacturing due to their unique properties and the benefits they can bring. Below, we’ll cover the basics — how are nanomaterials made, what are they and why are they essential to the manufacturing industry?

What Are Nanomaterials?

Nanomaterials are chemical substances and materials made up of very, very small individual units. Because of their small size, they often have unique properties that make them valuable in manufacturing.

Definitions of what counts as a nanomaterial vary. Most follow the one set by the European Commission. They define nanomaterials as any material made up of individual units between 1 and 100 nanometers in length. To give you a better idea of how small that is, the width of one strand of hair is around 100,000 nanometers — 10,000 to 100,000 times bigger than any nanomaterial.

This broad definition means that most nanomaterials are too small to be seen with the unaided eye. We can observe nanoparticles that occur in nature, but you will need a microscope or another tool to spot them. Some may even be too small to spot with standard laboratory microscopes.

Engineers usually design nanomaterials with a specific characteristic in mind. Some are designed to be insulating, while others are conductive. It’s also possible to include them as a component in existing designs to increase strength or reduce chemical reactivity, among a thousand other uses. 

Nanomaterials can both be synthetic — like carbon nanotubes and foam-like aerogels — and naturally-occurring, like volcanic ash.

Examples of Nanomaterials

We can break nanomaterials down into four types to make them a little easier to quantify. These include: 

• Inorganic-based nanomaterials, including metal and metal oxides
• Carbon-based nanomaterials, including graphene, fullerene and carbon nanotubes
• Organic-based nanomaterials include organic materials that exclude carbon-based materials.
• Composite nanomaterials include any combination of the three types mentioned above. 

In addition to being used individually, nanomaterials can be combined with other substances to change their properties or improve specific characteristics. 

How Are Nanomaterials Made?

Due to their small size and the precision needed to create them successfully, nanomaterials usually require specialized manufacturing processes.

There are two main production processes for nanomaterials. The first is top-down manufacturing, also known as the destructive approach. This method starts with large pieces of material. Chemical and physical processes break it down until the desired nanomaterial exists. Depending on the substance, this process can be relatively simple. Some metal nanoparticles, for example, can be ground down from microparticles with the right equipment.

Mechanical milling is the most common top-down method for producing nanomaterials, largely thanks to its straightforward nature. This process simply grinds material into increasingly fine particles to reduce their size and break apart components. However, manufacturers can also use light, heat, electrical charges, ions or lasers to break more sensitive resources into nanomaterials.

The second group of manufacturing processes is bottom-up or constructive manufacturing. These methods begin with single atoms or molecules. They use chemical and physical processes to join them together into useful nanostructures. Bottom-up approaches typically create the most unique and powerful nanomaterials but are more complicated than top-down processes.

Bottom-up nanomaterial synthesis methods tend to be more varied than destructive alternatives, as each material has unique needs required to grow. Some rely on chemical reactions, some change the conditions surrounding a material and others capitalize on biological processes to change materials.

Using Nanomaterials in Daily Life

Where might we use nanomaterials in our daily lives? The answer might surprise you, though there are some applications that you may never encounter unless you work in particular fields. The carbon-based nanomaterials we mentioned above, such as graphene and carbon nanotubes, all find their way into electronics. In pharmaceuticals, nanomaterials can carry and deliver medications within the body. 

In cosmetics, you’ll often find nanomaterials that include titanium dioxide and zinc oxide. You may even find some cosmetics that include gold or silver nanoparticles. These precious metals have potent antibacterial and antifungal properties. Titanium dioxide and gold and silver nanoparticles are also often used in food processing and packaging. 

Many of those same benefits make nanomaterials an ideal resource in cleaning products. Nano additives to fabrics help clothes resist bacterial growth or prevent stains. Similar nanomaterial properties appear in antibacterial cleaning solutions, degreasers, stain removers and air purifiers. Some paints contain these materials, too, to give them self-cleaning characteristics.

Nanomaterial coatings appear in a variety of industries. Suspended silver nanoparticles make mirrors, while other nanoparticles could be used to create anti-corrosive coatings on iron or steel to prevent oxidation damage over time. The applications for this technology are nearly limitless. 

Dangers of Nanomaterials

The identifying characteristic of nanomaterials — their size — also creates risk when working with them. These materials may be entirely benign when you encounter them in the world. Still, at a nanoscale, it becomes possible and even likely that you will inhale some of these materials or absorb them through your skin or mucous membranes. 

Research shows that inhaling fibrous carbon-based nanomaterials can create the same damage and irritation we’ve observed in patients exposed to asbestos. These inhaled particles can also carry dangerous chemicals or pollutants with them.

Some scientists are concerned that exposure to nanomaterials can create ‘free radicals’ within the body that can lead to cellular and DNA damage over time. Because nanoparticles are so small, they can pass through cell membranes under the right circumstances, leading to interference with cellular functions. There is also a risk that these particles, once introduced to the bloodstream, could cross the blood-brain barrier. 

We can mitigate these risks by utilizing proper personal protective equipment (PPE), including respirators designed to filter out nanoparticles from the air and other appropriate gear. Ventilation is another key safety practice. While lab chemical hoods are too turbulent for working with nanomaterials, HVAC systems that direct airflow away from workers’ faces and negative-pressure, HEPA filter-equipped ventilation can reduce inhalation-related hazards.

Why Nanomaterials Are Important to Manufacturing

Nanomaterials provide a range of valuable characteristics and are often potent alternatives to existing materials. For example, nanoscopic aerogels, foam-like materials manufactured by the sol-gel process, act as powerful insulators because of their composition. The complex networks of particles with pockets of air and gas trapped inside provide layers of insulation.

Nanometals made from materials like tungsten and titanium can make tools with cutting implements stronger and more resistant to wear. Thus, manufacturers can use them longer. Others can control pollution due to their high chemical reactivity compared to their size. They can react with pollutants, like nitrogen oxide and carbon monoxide, avoiding contamination in the combustion of fossil fuels.

Some nanomaterials have a wide range of uses. One of the best examples is carbon nanotubes. They have some extremely interesting properties — like better thermal conductivity than diamond, mechanical strength that outclasses steel and high electric conductivity. They’re also extremely light, which makes them an excellent alternative to metals. These qualities are useful in lightweight bicycle frames, batteries and transistors. Their composition — like a mesh, made out of a single layer of carbon atoms joined together in rings — also make them great filters. This has manufacturers looking at carbon nanotubes for use in water purification systems.

Even when fragmented throughout another material, carbon nanotubes still provide some of their unique properties. It’s possible to reinforce weak materials — like the plastic filament used in 3D printing —  with carbon nanotubes. This gives manufacturers a printing material that is both strong and lightweight.

Challenges in Manufacturing Nanomaterials

Unfortunately, carbon nanotubes are difficult to manufacture at scale. Researchers are constantly experimenting with new manufacturing methods, and we manufacture several thousand tons of carbon nanotubes around the world annually. However, production growth has been limited by challenges in both processes and in maintaining high levels of quality.

These materials’ unique health hazards may also pose an obstacle to nanomaterial production at scale. While best practices like proper ventilation and PPE have emerged, there is much researchers still don’t know about nanomaterial safety. Some safety measures are also expensive and complex. Consequently, it may take additional time and investment for manufacturers to make their facilities safe enough to produce nanomaterials on a large scale.

Costs and complexity aside, reproducibility and consistency are difficult to achieve at scale, leading to diminishing returns for manufacturers. More reliable processes and determining acceptable quality levels will help, but it may still be a long while before the world can mass-produce the most impactful nanomaterial applications.

How Nanomaterials May Change Manufacturing

Nanomaterials, despite their small size, are extremely valuable to manufacturers. These materials can provide a range of unique and fascinating properties — like increased conductivity, extreme strength and insulation. Often, these materials are also lightweight, making them great alternatives to durable materials — mostly metals, like steel — that are often very heavy.

While nanomaterials can remain hard to fabricate at scale, many manufacturers are increasingly investing in research and development to take advantage of the properties that these materials offer.

Featured Image Credit: Technology vector created by macrovector via Freepik

Editor’s note: This article was originally published on June 14, 2023, and was updated December 31, 2024, to provide readers with more updated information.