Nanotechnology also plays a significant role in the construction industry, with the steel, glass, and concrete industries holding the largest share in this regard. The application of nanoparticles in construction, particularly carbon nanotubes (CNT) and titanium dioxide (TiO2), generally enhances the mechanical properties of structural elements. In finishing works, nano-coatings applied to both interior and exterior building facades hold special importance. These coatings repel water, minimize dirt accumulation, and protect building surfaces from UV radiation.
Nano-coatings can be applied to various surfaces such as cement, brick, tile, natural stone, marble, wood, ceramics, glass, steel, and concrete. Other significant applications of nanotechnology in construction include the development of reinforced, self-healing, and self-cleaning concrete, fire-resistant and energy-controlling glass, and energy-saving materials. Additionally, nano-based paints prevent bacterial penetration in office buildings, residential structures, hospitals, and other environments, granting them longevity, a bacteria-free atmosphere, and resistance to dirt and deterioration.
It is evident that we are facing a new world of technology called nanotechnology. Experts believe that after the invention of steam engines, internal combustion engines, and the development of IT, nanotechnology will open new horizons for humanity. This technology enables the manipulation of materials at extremely small scales, allowing for their reconstruction and the introduction of new materials and technologies to the world.
For example, clay and ceramics can be broken down to the nanoscale, mixed with nano-polymers, and processed in a neutral environment to create highly durable materials that have never been seen before.
Nanotechnology and Building Coatings
Nano-coatings in buildings are applied to both interior and exterior surfaces, including glass, plastic, wood, steel, stone, brick, tile, ceramics, cement, and concrete. These surfaces, known as smart surfaces, are typically either superhydrophilic or superhydrophobic, allowing specific reactions to occur on the surface. Additionally, nano-coatings used in buildings are antibacterial and pose no harm to human health.
The Lotus Effect
Nano-Coatings for Stone and Wood
These antibacterial nano-coatings are resistant to water, air, organic and inorganic substances, making them essential components in the construction industry. Nano-coatings for stone and wood preserve the original appearance of surfaces while preventing adhesion of contaminants such as water, oil, and other pollutants. Additionally, these coatings are highly effective for porous stone surfaces with absorption properties.
The composition of these coatings usually includes elements such as diamond, silver, glass, and ceramics, which may vary depending on their applications. However, in most cases, they have a water or alcohol-based carrier phase and can withstand temperatures up to 300 degrees Celsius.
Advantages:
Coating porous surfaces
Maintaining surface breathability
Protecting surfaces from environmental factors
Easy cleaning of stains such as oils and grease with water
Preventing mold, algae, and similar growths
Protecting surfaces from moisture and dirt
Applications
Wooden Surfaces
Nano-coatings for stone and wood are applied not only to standard wooden surfaces but also to polished and painted wooden surfaces. On polished wood, they are applied three months after the polishing process, while multi-purpose nano-coatings are used on painted wooden surfaces.
Fiber Cement
Buildings constructed with fiber cement often become heavily stained over time. The cement used in building facades absorbs dirt and mold, embedding them deep into the matrix under sunlight, making them difficult to remove. Applying nano-coatings to these surfaces prevents dirt, bacteria, and other contaminants from penetrating the matrix, preserving the original appearance of the facade.
Bricks and Ceramics
Large trees surrounding buildings can cause staining on building surfaces, which can result in the building facades gradually taking on a green color from the trees. To clean them, strong pressure cleaners are typically required. However, this process often increases adhesion on the surface, leading to dirt being absorbed more easily and quickly than before. In such cases, the use of nano-coatings for stone and wood appears essential.
Sandstone and Aerated Concrete
Aerated concrete and sandstone, which often have a white structure and are used in galleries and verandas, absorb dirt and oils, causing their appearance to deteriorate rapidly. Even with strong pressure cleaners, these stains are difficult to remove. However, when nano-coatings for stone and wood are applied, they allow the surface to breathe while preventing substances from penetrating the surface, thereby maintaining the original color and structure.
Tiles and Stone Slabs
Nano-coatings for stone and wood ensure that buildings, along with their surrounding gardens and statues, remain protected from environmental impacts, preventing discoloration over time.
Glass
Nano-coatings on glass are widely used in both the construction and automotive industries. Below are some of their applications in the building industry:
Self-Cleaning Glass
These nano-coatings, applied with a thickness of a few nanometers, form a hydrophilic film on the glass surface. This hydrophilic surface, activated by sunlight, creates a photocatalyst effect. The water accumulated on the surface spreads evenly due to the forces of gravity and air, allowing the surface to self-clean effectively.
Nano-coatings applied to glass show their self-cleaning properties after six weeks. Experts claim that the TiO2 nanoparticles in these coatings have two key properties: super-hydrophilicity and antimicrobial action. TiO2 can break down and decompose organic pollutants, and this effect becomes apparent after a few weeks as the titanium dioxide is incorporated into the glass matrix. This action helps remove dirt and pollutants through catalytic decomposition without leaving any stains.
Energy-Control Glass
These types of glass come in various colors and other characteristics, and they reduce ultraviolet and infrared radiation while regulating visible light transmission. During the winter, they can prevent up to 85% of energy loss, and in summer, they reduce energy loss by up to 80%, contributing significantly to energy savings.
Fire-Resistant Glass
Fire-resistant glass is another achievement of nanotechnology. This product involves placing a transparent layer containing silica nanoparticles (SiO2) between two sheets of glass. When the glass heats up, this transparent layer transforms into a hard, dark, and fire-resistant barrier.
Concrete
Much research is being conducted on the use of nanotechnology in concrete structures. To better understand this, technologies such as AFM, SEM, and FIB microscopes, which are designed for studying materials at the nanoscale, are used.
Nano-Silica (SiO2)
By using nano-silica particles, the particle density in concrete can be increased. This enhances the micro and nanoscale structure of the concrete, leading to improved mechanical properties. Adding nano-silica to cement-based materials also helps control chemical degradation caused by calcium-silicate-hydrate (C-S-H), which occurs due to calcium leaching in water. It also prevents water from penetrating the concrete, both of which increase the durability of the concrete.
Carbon Nanotubes (CNT)
Extensive research is underway on the applications of carbon nanotubes, and remarkable properties have been discovered. For example, although the density of carbon nanotubes is one-sixth that of steel, their Young’s modulus is five times higher, and their strength is eight times that of steel. Adding just 0.5 to 1% by weight of these nanotubes to the concrete matrix significantly improves the properties of the samples. (Carbon nanotubes are available in single-walled or multi-walled forms.)
Nano-Clay Particles
Some types of nanoparticles in various binders (such as mortar) affect key characteristics related to concrete wear, such as preventing chloride ion transfer, resistance to carbon dioxide, vapor permeability, water absorption, and depth of penetration. A solution made from low molecular weight epoxy resin combined with nano-clay particles has shown promising results in this area.
Iron Oxide Nanoparticles (Fe2O3)
Adding iron oxide nanoparticles to the concrete matrix not only increases its strength but also enables monitoring of stress levels through electrical resistance measurements.
Titanium Dioxide Nanoparticles (TiO2)
Titanium dioxide nanoparticles are used in concrete for improving the appearance of building facades as reflective coatings. These nanoparticles can break down and decompose organic pollutants and volatile organic compounds (VOCs) through strong photocatalytic reactions.
Steel
Steel is one of the most important metals in the construction industry. Research has shown that adding copper nanoparticles to steel reduces the surface roughness of the steel, thereby limiting the factors that increase stress and ultimately fatigue-induced cracks in structures such as bridges and towers, where loading is applied intermittently.
Sensors
Nano-based sensors can also have numerous applications in concrete structures. For quality control and durability of concrete, these sensors can be designed to measure various parameters such as density, concrete shrinkage, factors influencing concrete durability including temperature, humidity, chloride concentration, pH, carbon dioxide, stress, corrosion of rebars, and vibrations.