A look at nanomaterials currently being applied to a wide variety of surfaces with multi-functional properties inside and outside buildings.
Nanomaterials are particularly suited to protecting the surface of various construction materials such as glass, concrete, sand limestone or marble from environmental influences like water staining, moss, algae as well as soot and oil stains; and also function as corrosion inhibitors for reinforced steel. Paints and surface coatings are commercially available that create a low energy facing thus rendering a building surface highly hydro- and oleophobic, thereby helping to prolong maintenance cycles and reduce cleaning.
Dirt repellent protective paints and photocatalytic coatings are the most prominent applications in the construction and exterior protection industry. Dirt collection (accumulation) in building exteriors poses considerable problems for building maintenance. Cleaning such building surfaces is generally done by using detergents accompanied with scrubbing, wiping and high-pressure water jets. These processes have several shortcomings such as use of chemical detergents, high consumption of energy and labour cost. This naturally leads to high maintenance costs; therefore, an effective self-cleaning coating is desirable. In recent years, self-cleaning coatings using photocatalytic Titanium Dioxide (TiO2) have gained considerable industry attention. With assistance of little UV light from fluorescence source or sunlight, TiO2 offers two unique properties: (a) strong oxidation power, and (b) super-hydrophilicity. Strong oxidation power can be used to kill bacteria attached on the wall, or oxidize/remove foul smells from stains in toilets (e.g., TiO2-coated tile and TiO2-coated glass are commercially available). Super-hydrophilic properties allow dirt and stains to be easily washed away with water or by rainfall when such a coating is applied to exterior surfaces.
Nanopowders have been added to construction ceramics which include floor and wall tiles, countertop ceramics and sanitary ware products have found place on the market with self-cleaning, anti-bacterial, hygienic and scratch resistant features. This is one of the largest markets for nanomaterials and will continue to grow significantly in the next decade.
Ceramics
Nanopowders have been added to construction ceramics, which include floor and wall tiles, countertop ceramics and sanitary ware products that have found place on the market with self-cleaning, anti-bacterial, hygienic and scratch resistant features. Nanoparticles exhibit properties of water/dirt repellency, UV protection, antibacterial, anti-corrosion for application on glass.
Easy-clean/Anti-fouling
Anti-fouling and easy-to-clean nanocoatings have gained impressive market traction, especially in the building materials, marine and household (mainly bathroom) sectors. A number of large multinationals, including Evonik Degussa, Dupont, Schott, 3M and Corning produce anti-fouling and easy-to-clean coatings for a variety of markets.
Self-cleaning Coatings
Nanoparticle TiO2 self-cleaning coating greatly benefit building maintenance, especially for skyscrapers, as they reduce the need for costly surface cleaning. Photocatalyst coatings are also used to improve indoor air quality by reducing the amount of volatile organic compound and other toxic chemicals people are exposed to in hotels, restaurants, commercial business facilities, university laboratories, hospitals and residences.
UV-resistant
Nanovations’ Lignol wood coatings are water-based, VOC-free, clear impregnating wood coatings containing nanoscale UV absorbers. Nanovations 3001, designed for use on masonry and concrete surfaces, provides superior water repellency, reduces efflorescence, and provides significantly improved abrasion resistance.
Deck Coatings
There are a number of nano-enabled products for the protection and cooling of wooden decks and railings. These transparent protective coating help to cool deck surface temperatures as well as protect the wood from moisture, UV and weathering, while also being resistant to mold and algae growth.
Paint
Rheology, settling, surface energy, corrosion resistance and mechanical properties of paint can be improved via the addition of nanoparticles. Adding nanoparticles gives paint scratchproof, easy cleaning, air purifying, UV resistant, water repellence, flame retardancy and anti-bacterial features.
Anti-Microbial Coatings
Silver nanoparticles have been commercialized that destroy mold and mildew, fungi spores, and bacteria on contact. The nanoparticles are stabilized with additives and integrated homogeneously into the polymer matrix. Antimicrobial activity does not decrease with time because the solid nanoparticles are not volatile, like many commonly used biocide additives.
Anti-graffiti
Anti-stick properties of nanocoatings leads to less staining and easy-cleaning-effect on exterior and interior surfaces. Anti-graffiti properties mean that stubborn stains such as graffiti, which in the past called for intensive cleaning efforts can be washed away simply with a high pressure hose.
