What are Nanomaterials?
Nanomaterials can be defined as materials possessing, at minimum, one external dimension measuring 1-100nm. The definition given by the European Commission states that the particle size of at least half of the particles in the number size distribution must measure 100nm or below.
Nanomaterials can occur naturally, be created as the by-products of combustion reactions, or be produced purposefully through engineering to perform a specialised function. These materials can have different physical and chemical properties to their bulk-form counterparts.
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. 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.
The second group of manufacturing processes is bottom-up 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.
How Can Nanomaterials Be Characterized?
Nanomaterials can occur naturally, be created as byproducts of combustion reactions, or be intentionally produced through engineering to perform a specialized function. They can be physically and chemically characterized to determine their size, shape, composition, and structure.
Physical Characteristics:
- Transmission Electron Microscopy (TEM): TEM uses high-energy electrons to produce images of nanomaterials, providing information on their size, shape, and arrangement.
- Scanning Electron Microscopy (SEM): SEM uses a focused beam of electrons to produce images of the surface of nanomaterials, providing information on surface morphology and topography.
- Dynamic Light Scattering (DLS): DLS measures the Brownian motion of particles in solution, providing information on particle size distribution.
- X-ray diffraction (XRD): XRD uses X-rays to determine the crystal structure of a material and identify its components.
Chemical Characteristics:
- Energy Dispersive Spectroscopy (EDS): EDS uses X-rays to analyze the composition of nanomaterials by measuring the energy spectra of electrons emitted from the sample.
- Fourier Transform Infrared Spectroscopy (FTIR): FTIR uses infrared light to measure a material’s vibrational spectra of chemical bonds, providing information on its chemical composition.
- X-ray photoelectron spectroscopy (XPS): XPS uses X-rays to excite electrons in a material, providing information on its chemical composition and electronic structure.
- Inductively Coupled Plasma-Mass Spectrometry (ICP-MS): ICP-MS uses a plasma torch to vaporize and ionize a sample, and then measures the mass of the ions to determine the composition.
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.
What are the uses of Nanomaterials?
Due to the ability to generate the materials in a particular way to play a specific role, the use of nanomaterials spans across various industries, from healthcare and cosmetics to environmental preservation and air purification.
The healthcare field, for example, utilises nanomaterials in a variety of ways, with one major use being drug delivery.
One example of this process is whereby nanoparticles are being developed to assist the transportation of chemotherapy drugs directly to cancerous growths, as well as to deliver drugs to areas of arteries that are damaged in order to fight cardiovascular disease.
Carbon nanotubes are also being developed in order to be used in processes such as the addition of antibodies to the nanotubes to create bacteria sensors.
In aerospace, carbon nanotubes can be used in the morphing of aircraft wings. The nanotubes are used in a composite form to bend in response to the application of an electric voltage.
Elsewhere, environmental preservation processes make use of nanomaterials too – in this case, nanowires. Applications are being developed to use the nanowires – zinc oxide nanowires- in flexible solar cells as well as to play a role in the treatment of polluted water.
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.
Examples of Nanomaterials
The use of nanomaterials is prevalent in a wide range of industries and consumer products.
#1. Titanium Oxide.
In the cosmetics industry,mineral nanoparticles –such as titanium oxide –are used in sunscreen, due to the poor stability that conventional chemical UV protection offers in the long-term.
Just as the bulk material would, titanium oxide nanoparticles are able to provide improved UV protection while also having the added advantage of removing the cosmetically unappealing whitening associated with sunscreen in their nano-form.
#2. Carbon Nanotubes.
The sports industry has been producing baseball bats that have been made with carbon nanotubes, making the bats lighter therefore improving their performance.
Further use of nanomaterials in this industry can be identified in the use of antimicrobial nanotechnology in items such as the towels and mats used by sportspeople, in order to prevent illnesses caused by bacteria.
#3. Mobile Pigment Nanoparticles.
Nanomaterials have also been developed for use in the military. One example is the use of mobile pigment nanoparticles being used to produce a better form of camouflage, through injection of the particles into the material of soldiers’ uniforms.
Additionally, the military have developed sensor systems using nanomaterials, such as titanium dioxide, that can detect biological agents.
#4. Nano-Titanium Dioxide.
The use of nano-titanium dioxide also extends to use in coatings to form self-cleaning surfaces, such as those of plastic garden chairs.
A sealed film of water is created on the coating, and any dirt dissolves in the film, after which the next shower will remove the dirt and essentially clean the chairs.
Advantages of Nanomaterials
Nanotechnology and nanomaterials can be applied in all kinds of industrial sectors. They are usually found in these areas:
#1. Electronics.
Carbon nanotubes are close to replacing silicon as a material for making smaller, faster and more efficient microchips and devices, as well as lighter, more conductive and stronger quantum nanowires. Graphene’s properties make it an ideal candidate for the development of flexible touchscreens.
#2. Energy.
A new semiconductor developed by Kyoto University makes it possible to manufacture solar panels that double the amount of sunlight converted into electricity.
Nanotechnology also lowers costs, produces stronger and lighter wind turbines, improves fuel efficiency and, thanks to the thermal insulation of some nanocomponents, can save energy.
#3. Biomedicine.
The properties of some nanomaterials make them ideal for improving early diagnosis and treatment of neurodegenerative diseases or cancer.
They are able to attack cancer cells selectively without harming other healthy cells. Some nanoparticles have also been used to enhance pharmaceutical products such as sunscreen.
#4. Environment.
Air purification with ions, wastewater purification with nanobubbles or nanofiltration systems for heavy metals are some of its environmentally-friendly applications. Nanocatalysts are also available to make chemical reactions more efficient and less polluting.
#5. Food.
In this field, nanobiosensors could be used to detect the presence of pathogens in food or nanocomposites to improve food production by increasing mechanical and thermal resistance and decreasing oxygen transfer in packaged products.
#6. Textile.
Nanotechnology makes it possible to develop smart fabrics that don’t stain nor wrinkle, as well as stronger, lighter and more durable materials to make motorcycle helmets or sports equipment.
Disadvantages of Nanomaterials
Alongside their benefits, there are also a number of disadvantages associated with nanomaterial use. Due to the relative novelty of the widespread use of nanomaterials, there is not a large amount of information on the health and safety aspects of exposure to the materials.
Currently, one of the main disadvantages associated with nanomaterials is considered to be inhalation exposure.
This concern arises from animal studies, the results of which suggested that nanomaterials such as carbon nanotubes and nanofibers may cause detrimental pulmonary effects, such as pulmonary fibrosis. Further possible health risks are ingestion exposure and dust explosion hazards.
Additionally, there are still knowledge gaps regarding nanomaterials, meaning the manufacturing process can often be complex and difficult.
The overall process is also expensive, requiring optimum results – especially regarding their use in consumer goods – in order to avoid financial losses.
Risk-assessments concerning any potential environmental effects indicate that nanomaterials used in cosmetic items such as sunscreen, which are applied to the skin, run the risk of ending up in aquatic ecosystems after they are washed off.
Nanomaterials that have been engineered may also end up in water bodies such as lakes and rivers, before accumulating to create particles of a larger size. This may put freshwater species – such as snails- at risk by possibly inducing a decline in life processes such as growth and reproduction.
The same issues caused by the materials in such freshwater ecosystems are likely to pertain to marine ecosystems as well. Accumulation of nanomaterials in other aspects of the environment, such as soils – through sewage sludge – is an additional concern.
Although the concentrations of these engineered nanomaterials is expected to be quite small, repeated release may cause the concentrations to increase over time, exacerbating the related negative effects.