Nanomaterials on Earth and Beyond Series
Coatings are expected to constitute the largest application for nanomaterials in near-term construction. Nanomaterial coatings bind to the base material to produce a surface of the desired functional and protective properties (fire protection, heat insulation and corrosion protection). These coatings are usually produced by using Chemical Vapor Deposition (CVD- a chemical process to produce high performance, high purity solid materials by passing volatile vapors over a substrate.), Dip (i.e. immersing a substrate into the nanomaterial solution), and Spray (i.e. spraying the substrate with the nanomaterial solution) (9).
Some of the current nanomaterial coatings in the construction industry include architectural paints, water sealers, deck treatments, scratch-resistance coatings, anti-microbial coatings, self-cleaning surfaces, UV blocking , stain resistant and odor resistant.
The most prominent of coating materials is TiO2, which was covered in more detail in an earlier section. Pilkington, St. Gobain Co., and others are already marketing self-cleaning glasses based on these TiO2 coatings. Another approach to creating self-cleaning glass is based on replicating the spotless lotus leaves and marketed by BASF as “lotus-spray” products (25). The product is expected to be 20 times more water-repellent property than a smooth, wax coating and retain its lotus effect even after an abrasion with sandpaper. Nanomaterial coatings can also be used to build intelligent glass that blocks heat but not light (26). For example vanadium dioxide coatings can be used to absorb infrared light above a certain temperature (27). Additionally coatings using an acrylic primer made up of a unique combination of Nano structures called NanoCNB (28) act as thermal insulators by reflecting heat back to the room. This technology originally developed by NASA to combat high temperatures encountered by space shuttles, acts by altering the floor/walls ability to absorb heat from the room, thus reflecting the heat back into the room.