Nanomaterials: short History and Applications

Written by: Fernanda Monasterio

Materials Science always tagged along with the achievements that improve our quality of life. It is not a matter of natural selection but, during this continuously-evolving process, only the best material survives.

Lead and fiberglass are good examples of it. The first uses of lead date back to 4,000 B.C. Egypt and, later, it had several applications, like piping, during the Roman Empire [1]. As a matter of fact, lead was the favorite metal used in piping for a long time. However, its negative impact on human health made it necessary to replace it for pipes made out of other materials like Polyvinyl Chloride (PVC).

Meanwhile, fiberglass has also been around for a very long time. However, it was first produced at an industrial scale during the 20th century. It was used initially as an isolating material, but its chemical strength, flexibility, and transparency, among other properties, made it possible for it to be used for different purposes. It is particularly important its use in optical fiber and how it replaced copper for enabling Internet connection thanks to its fastest transmission rate.[2]

These are two common materials whose applications have changed because of the way we use them in different activities. Besides, on top of this continuous-improvement process, there was enormous progress made in Science which translated into the evolution of the fields of Nanoscience and Nanotechnology, which also pushed the study of Nanomaterials.

Nanotechnology caused a revolution in the Materials field because the handling of materials’ internal structure had never been performed at such a small scale with such precision. [3]

Several examples of current applications of nanomaterials can be found on the following table:

Application	Common Material	Improved Material
Construction	Concrete	Modified concrete with nano titanium dioxide (TiO2)
Food packaging	Plastic (polyethylene, PE)	Plastic with nanosilver (Ag)
Water purification	Ceramic and polymer materials and metals.	Filters with carbon nanotubes.
Dental care	Ionomers, resin mix, silver amalgam.	Composites with nanoceramics.

Regarding concrete, it has been observed that the added nanomaterial helps with pollutant degradation thanks to the photocatalytic activity present in TiO2. There are constructions already built with this material and other products like self-cleaning glass and cosmetics that also use TiO2 [5,6].

Street in Antwerp and paving stones with TiO2 used in construction, extracted from the Boonen and Beeldens article, 2014 [7].

Self-cleaning glass skating rink dome in Vancouver, extracted from the Wroblaski article, 2010

The use of nanosilver is very useful for food packaging since it acts as a biocide, preventing mold and deterioration of the product, thus enabling its storage for longer periods of time.[8]

Water quality improvement is always a constant field for research since water is a scarce and vital resource for humanity. Through research, membranes with carbon nanotubes were developed to achieve this goal. Said nanomaterials not only add better mechanical properties to these membranes but also present greater flows and efficiency regarding salt rejection. They are used both for water desalination and the oil or pollutant removal. There are many research studies being conducted in this area and the market is constantly growing. [9,10]

Finally, nanomaterials can also be found in the dental care field. Nanotechnology has had such an impact on this area that there are already talks of the development of nanodentistry, where new biomaterials and even nanorobots would be used. Dental braces made of nanoceramics of different color shades that improve the look of the patient can already be found in the market. [11,12]

Toxicological effects of nanomaterials

The scientific community is very well aware of the need to analyze the possible effects of these new materials since there is evidence that proves that, in case of intake, inhalation or skin absorption, these nanomaterials can cause damage not only to humans but to other living beings too.

There are studies that show that rats may develop microvascular dysfunction when exposed to TiO2 nanoparticles and that carbon nanotubes may cause vascular thrombosis. However, there are still no systematic or conclusive studies about the real effect these nanomaterials may cause. [13]

Current prospects and limitations for nanomaterials

The list of nanomaterials and their current and future applications can go on forever. However, we are going to touch on two that are particularly interesting for many companies: graphene and nanocellulose.

Due to the high potential of graphene’s properties, several companies (2D Carbon Tech, ACS Material, Advanced Graphene Products, among others), are focused on its production and are investing on this nanomaterial. For instance, the company Saint Jean Carbon announced the manufacturing of lithium-graphene based batteries in 2017. However, there have been warnings regarding the high expectations some companies are raising towards their products, which is why information is key before making any investments. [14]

It is predicted that in 2023 the nanocellulose market will reach the USD 661.3 M thanks to the growing demand of the paper and pulp industry. The electronic and sensor market is the one that promises a particularly high compound annual growth rate. Some of the companies in this sector are Innventia (Sweden), American Process (USA), FPInnovations (Canada). [15]

Beyond the potential toxicological and environmental effects, there are limitations regarding the classification of nanomaterials which hinder their regulation. This has consequences especially when nanomaterials are taken to market, which is why some criteria should be defined to achieve their future implementation.