Posting in Science
What if surface coatings could clean furniture and gadgets simply through exposure to sunlight?
A particularly hard rain or your garden furniture left abandoned for a little too long, and the task of dusting everything off is necessary before you can invite your friends over for that BBQ you've kept cancelling.
But what if your furniture cleaned itself as soon as the sun breaks through the clouds?
Activated by UV light, plastic surfaces containing titanium dioxide molecules trigger a chemical reaction which produces free radicals. The electrochemical reaction of the titanium dioxide and other active molecules attack bacteria, algae and fungi. At first, the molecules destroy the cell walls, and then penetrate the cytoplasm -- damaging bacterial DNA, wiping out its ability to grow.
Researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart have been developing a merged compound of plastic and titanium dioxide in order to test how well these photocatalytic coatings work.
Testing the effectiveness of the coating on a range of other surfaces in the lab, 30 different kinds of fungal, bacterial and algal cultures were applied. In addition, the team analyzed the degradation rates and products caused by the self-cleaning surfaces and the subsequent chemical reactions.
Some of the tests the team have conducted include running outdoor trials on garden chair armrests with photocatalytic coatings and comparing them to ones made from conventional plastic. Spraying the armrests with a mixture of various bacteria, mosses, algae and fungi, the chairs were left exposed to the weather for two years.
At the end of the trial, the coat of dirt was almost impossible to remove from the normal armrests -- but the photocatalytic plastic furniture was nearly completely clean and white.
It is not only furniture that may be getting the self-cleaning treatment. The scientists have also developed a coating for glass surfaces. Dr. Michael Vergöhl, head of department at the Fraunhofer Institute said:
"If you apply a thin coating of titanium dioxide to a glass surface such as a smartphone screen, the skin oils and fingerprints gradually disappear from the display by themselves."
The glass version only needs one hour of sunlight to be effective. However, the next path the team want to pursue is to develop materials that can be activated by artificial light.
(via Science Daily)
Image credit: Fraunhofer-Gesellschaft
Jul 19, 2012