It's summer and time to wipe off the lawn furniture. Wouldn't it be great if the dirt on it just disappeared by itself?
At the Fraunhofer institute in Germany, a team has developed something that sounds like an infomercial product: a coating of titanium dioxide-doped polymers that, when exposed to sunlight, kill germs and might get rid of that funky black mold.
It works because when sunlight hits the titanium dioxide, the ultraviolet rays act as a kind of catalyst, triggering an electrochemical reaction that produces free radicals, the molecules that have a single electron on their surfaces. Free radicals destroy cell walls and infiltrate the DNA inside, damaging it and thereby killing bacteria and fungi. Likewise, the grim and goo these organisms create is also eliminated.
According to Iris Trick, group manager at the Fraunhofer Institute for Interfacial Engineering and Biotechnology, the formula works on 30 different kinds of bacteria and fungi.
There are uses beyond spotless furniture, though. The Fraunhofer team found that putting the titanium dioxide molecules on glass keeps it clear of fingerprints: they just disappear after an hour's exposure to sunlight. Any smartphone owner can appreciate that. While there are surfaces that do that now, they take three hours of exposure to the sun to get the same result.
Credit: Fraunhofer Institute