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Nanoparticles are an interesting material; they exist between being a complete bulk material and an atomic particle. Sized between 100 and 2500 nanometers, the particles are larger than atoms and smaller than bulk material. As well as in size, nanoparticles can also differ in properties, as particles of a bulk material change properties as they reach nano size.
What are Nanoparticles?
For example, copper bends, but copper particles smaller than 50 nm are not considered malleable. For this reason, nanoparticles are of use to the construction industry as they offer properties that can be used advantageously in different building scenarios. For example, buildings can benefit from the addition of nanoparticles to make them stronger, resistant to fire and dirt build-up, self-cleaning and self-healing. Nanoparticles can even be added to purify the air. The range of uses and benefits are discussed below.
Types of Nanoparticles
One of the most commonly used nanoparticles in construction is titanium dioxide (TiO2). It acts as a photocatalyst which absorbs light to bring it to a higher energy level and can be used to catalyze a chemical reaction. These reactions can be utilized to make a building self-cleaning, like the Jubilee Church in Rome, created by Richard Meier and Partners, which is an example of modern construction using self-cleaning facade systems. The Marunouchi Building in Tokyo and the 40 Bond Street Apartment in London are also notable examples of this kind of technology. The reactions can also have antibacterial effects, as well as making the building resistant to fire and corrosion. For example, buildings coated with TiO2 when exposed to UV light automatically break down dirt and pollution, which is then washed away when it rains.
Another common nanoparticle is silicon dioxide (SiO2). It is used to reinforce the strength of concrete, but can also provide fire-resistant properties, as well as adding anti-reflection properties to windows. The nanoparticle can also be used to prevent algae and fungi growth and protects against pollution.
Zinc oxide is a nanoparticle used in sunscreen to help provide UV resistance. In buildings, it can also protect against UV light, as well as making materials scratch resistant and protecting against the formation of bad smells and mold.
Applications of Nanoparticles
Nanoparticles are often added to buildings for their insulating properties. Silica-based materials are used to create gels that are up to 97% trapped air within the silica framework which act as effective insulators. The gel is known in the industry as “frozen smoke” due to its extremely low density structure thanks to the silica nanoparticles allowing it to be highly porous. Nano silica is also used to boost the strength of concrete, an effect that can also be achieved by adding iron oxide nanoparticles, which also creates abrasion-resistant concrete.
Further to this, copper nanoparticles have proven their benefits in adding corrosion resistance and weldability to steel. Similarly, silver nanoparticles successfully add a biocidal effect to coatings and paints, lessening the impact of harmful organisms on the building.
Disadvantages of Nanoparticles
There are some drawbacks to using nanoparticles in construction, such as that their small size which results in an increased substance surface area, adding to their toxicity. They are easily inhaled and certain sized particles can find themselves lodged within the body, usually the lungs. For this reason, they are to be handled with care and construction workers require proper protection to prevent their impact on the body. However, their use is regarded as key to creating a sustainable future for the construction industry. In order to create buildings that are high performance, healthy, long-lasting and low maintenance, nanoparticles are essential.