The microscopic structural problems that cause mines to collapse, wind turbines to crash, and bridges to fail are often impossible to detect before it’s too late. Even when they aren’t, traditional structural sensors can cost millions of dollars each year to maintain. Researchers at Glasgow’s University of Strathclyde have an alternative: smart paint.
The paint, which is made out of carbon nanotubes and fly ash, is sprayed onto surfaces much like any other kind of paint. But this paint is special—it communicates wirelessly with battery-powered electrodes that are attached to the structure to detect structural micro-cracks.
Dr. Mohamed Saafi, one of the researchers behind the project, explains how the paint works in an email: "When damage occurs, the conductivity of the paint changes, [indicating] damage. The paint is also designed to react to selective environmental agents such as corrosion to chloride, moisture, and CO2 present in structures. So if the paint is subjected to chloride or moisture, the internal structure of the paint changes, allowing the alteration of the conductivity."
In other words, any changes in the paint’s electrical current—a sign of damage—are communicated to the electrodes, which in turn signal a problem to humans, who can then go check out the microfractures that before would have gone entirely unnoticed. Ideally, Saafi and team would like to power the electrodes with vibrations (i.e., from cars driving over a bridge).
So far, the researchers have only built a prototype of the paint and electrode system. But Saafi is hopeful about the potential for more testing in the future. And since the system costs just 1% compared to other structural monitoring techniques, we should be hopeful too.