138 - Construction Industry Institute

Whi te Pa per # X X X ( Dr af t: 0 6 / 1 8/ 2 0 1 2)
Au t h or : Gab riel Da di
B rea kt h r o ugh St r at eg y C o mmit t e e
SmartCoats: Intelligent and Innovative Material Coatings
1. Need and Potential
One is self-healing, one is water-proof, and one changes color when stressed. No, these are not superheroes
from the Avengers. These are some examples of new advancements in nanotechnologies and polymers. A new
generation of smart coatings allow for intelligent properties to critical construction materials. Could these
“SmartCoats” be applied for construction use, and what benefit could they provide? Are there other SmartCoats that
could be employed or developed?
2. Background and Gaps
The development of nanotechnologies and more specifically nanomaterials has allowed for exciting new
material properties that can be engineered at the smallest of dimensions. Beginning in the 1910s, Zsigmondy used an
ultramicroscope to study gold sols and other nanomaterials less than 10 nm in size. The ultramicroscope uses a dark
field method for viewing molecules that are small than the wavelength of light (Zsigmondy, 1914).
The study of nanotechnologies emerged further in the 1980s after the invention of the scanning tunneling
microscope in 1981. The scanning tunneling microscope allows for imaging of surface at an atomic level that later
won a Nobel Prize in Physics for Gerd Binnig and Heinrich Rohrer at the IBM Zurich Research Laboratory (Binnig
and Rohrer, 1986).
However, commercialization of nanotechnology products did not begin until the early 2000s, leading to
national funding efforts such as the National Nanotechnology Intiative. The first approved for sale nanotechnologies
were silver nanoparticles as an antibacterial agent, nanoparticle transparent sunscreens, and carbon nanotubes for
stain-resistant fabrics (Analysis, 2008).
3. State of the art
Three potential nanotechnologies with applications for the construction industry have recently emerged in a
Self-Healing Circuit, Never Wet, and Smart Paint. Each provides a unique property to materials frequently used in
construction projects that could ultimately improve performance of the materials.
The Self-Healing Circuit was developed at the University of Illinois by Professors Nancy Sottos, Scott
White, and Jeffrey Moore. The impetus behind their product is that electronic chips are being packed with high
density into the smallest form as possible. This can lead to reliability issues from the changing temperatures within
the circuit. When a failure occurs within the circuit, the entire system is typically replaced as it is difficult to open
the circuit up and manually repair the source of the problem (White, 2011). The same goes for batteries or any other
electronic device with small electronic components. Therefore, the team developed self-healing polymer materials
that are essentially tiny microcapsules about 10 microns in diameter. The microcapsules are coated along the
exterior of the component so that when a crack develops, the microcapsules fractures and release a liquid metal. The
liquid metal fills in the crack in the circuit and allows electrical flow to continue (White, 2011). A graphic of the
process can be seen in Figure 1.
Figure 1. Self-Healing Circuit process (White, 2011)
Never Wet is a “superhydrophobic” coating that repels any liquid that comes in contact with the product.
Water, syrup, and any other liquid simply roll off the surface of any material that has been coated with Never Wet.
However, its applications do not end there. Never Wet can be used as an antibacterial coating, an ice repellent, as
well as a corrosion repellent (Sorrel, 2011). All three are critical properties for several, frequently used construction
materials. There are some chemicals, however, that will wash the Never Wet coating off. Alcohol and mild soaps
will render Never Wet useless until another coat is applied (Sorrel, 2011). From electrical lines to drywall to
exposed metal, there are many applications of Never Wet for construction.
There have been several new products in the realm of smart paints in the past few years, but none have
come as close to a breakthrough application in the construction industry until this recent “smart paint” technology. A
mixture of carbon nanotubes and fly ash, this new Smart Paint could help prevent structural failures and improve on
structural monitoring technologies (Melanson, 2012). When the nanotubes are bent, the internal conductivity
changes, which would signal that a structural issue may soon occur. Electrodes can be attached that will alert the
proper parties that the issue is developing. By also incorporating fly ash, a cementitious product, the paint will also
be able to help hold some of the loading until a more elaborate fix can be implemented (Melanson, 2012). Dr.
Mohamed Saafi of the University of Strathclyde’s Department of Civil Engineering in Scotland believes that the
material has an advantage “as no expertise is required and monitoring itself is straightforward… it costs just 1% of
the alternative widely used inspection methods (Melanson, 2012).”
4. Recommended Path Forward
Nanotechnologies appear to be on the verge of major breakthrough commercial applications, especially
in the area of nanomaterials and coatings. There are even several nanomaterials that are being developed specifically
for use in the construction industry. A CII research team could further evaluate the Self-Healing Circuit, Never Wet,
and Smart Paint in specific construction applications. In addition, the research team could seek to identify other
intelligent coating systems in other industries that have the potential for a direct or indirect application in the
construction industry.
5. References
“Analysis: This is the first publicly available on-line inventory of nanotechnology-based consumer products.”
(2008). The Project on Emerging Nanotechnologies.
Binnig, G., and Rohrer, H. (1986). “Scanning tunneling microscopy.” IBM Journal of Research and Development,
30, 4.
Melanson, D. (2012). “Nanotech-enhanced ‘smart paint’ promises to detect structural damage.” Engadget. AOL
Tech. http://www.engadget.com/2012/01/30/nanotech-enhanced-smart-paint-promises-to-detect-structuralda/
Sorrel, C. (2011). “Spray-On ‘NeverWet’ Coating Could Waterproof Gadgets.” Gadget Lab. WIRED.
White, S. (2011). “Self-healing electronics could work longer and reduce waste.” University of Illinois News
Bureau. University of Illinois at Urbana-Champaign. http://news.illinois.edu/news/11/1220selfhealing_ScottWhite_NancySottos_JeffreyMoore.html
Zsigmondy, R. (1914). "Colloids and the Ultramicroscope", J.Wiley and Sons, NY.