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    Credit: Peter Arkle

Paint is a ubiquitous and versatile material, used to seal, protect, and enliven surfaces. It is also one of the oldest substances used by human beings, as evidenced by cave paintings that date to some 42,000 years ago—earlier than any known form of building. Today, the international demand for paint is strong. Although the global market is still rebounding from the recent recession, the International Paint and Printing Ink Council reports that 27.2 billion liters of decorative coatings were used globally in 2009.

As the thin veneer that separates a building or object from its environment, paint performs an important protective role with minimal depth. Despite this attenuated boundary, though, scientists have been attempting to expand paint’s functionality with the integration of a variety of new technologies.

Photocatalytic technology, for example, is applied to paint in order to improve local air quality. Boysen’s KNOxOUT paint incorporates a titanium-dioxide additive, which neutralizes physical particulates in the presence of sunlight—causing them to drop out of the air. With the claim that 1 square meter of the smog-busting coating can eliminate 10 cars’ worth of emissions, the company recently donated the paint to street artists in Manila, one of the world’s most polluted cities.

Another new technology enables paint to become a seamless, large-scale sensor. Developed by researchers at Glasgow, Scotland’s University of Strathclyde, Smart Paint is produced with an integral sensory network of carbon nanotubes. This network is devised to detect microscopic flaws in surfaces prior to the development of major structural problems. “Current technology is restricted to looking at specific areas of a structure at any given time,” says Mohamed Saafi of Strathclyde’s Department of Civil Engineering. “However, smart paint covers the whole structure, which is particularly useful to maximize the opportunity of preventing significant damage.”

Concern over future energy scarcity has encouraged research into the development of creative renewable-energy technologies, including solar energy–harvesting paint. Although past attempts to develop such a coating have been thwarted by low electrical-conversion rates, the University of Notre Dame’s Center for Nano Science and Technology in Indiana recently announced an improved formulation based on the inclusion of power-generating nanoparticles.

“We want to do something transformative, to move beyond current silicon-based solar technology,” states Notre Dame professor Prashant Kamat. “By incorporating power-producing nanoparticles, called quantum dots, into a spreadable compound, we’ve made a one-coat solar paint that can be applied to any conductive surface without special equipment.”

The paint, which has been named “Sun-Believable,” offers a conversion efficiency of 1 percent—a quantity far below the 15 percent conversion rate of commercial solar cells. “But this paint can be made cheaply and in large quantities,” Kamat says. “If we can improve the efficiency somewhat, we may be able to make a real difference in meeting energy needs in the future.”

If you'd like to read more cutting-edge technology and products coverage from Blaine Brownell, check out his Mind & Matter blog on this website.