If there's one thing that needs to be antibacterial, it's the public touchscreen displays that everyone paws at with their filthy fingers. Well, help is on the way, in the form of a newly developed copper coating.
While copper is known for its ability to kill bacteria on contact, it's also opaque and electrically conductive … neither of which are good qualities for something that will be covering a touchscreen.
The new "transparent nanostructured copper surface" (TANCS) was developed with these limitations in mind. It was created by a team of scientists from Spain's Catalan Institution for Research and Advanced Studies (ICREA), Institute of Photonic Sciences (ICFO) and the Corning corporation.
The researchers started by depositing a 3.5-nanometer-thick copper film onto a Corning Gorilla Glass substrate. In a process known as rapid thermal annealing, they then heated that film to 390 ºC (734 ºF), held it at that temperature for 10 minutes, then cooled it. Doing so caused the previously uniform film to "dewet" into a myriad of individual evenly-spaced copper nanoparticles.
The resulting altered film retained the copper's antibacterial qualities but became transparent, color-neutral and electrically non-conductive. Layers of silicon dioxide and fluorosilanes (water-and oil-repelling chemicals) were finally added over top of the film for added durability and environmental protection.
In tests performed under dry real-world conditions, the TANCS was found to kill 99.9% of applied Staphylococcus aureus bacteria within two hours. It also remained intact and effective after being subjected to the equivalent of being wiped down with cleansers twice a day for two years.
"While further development is necessary for full-fledged commercial deployment, this is a step in the right direction to enable antimicrobial touchscreens for public or personal displays," says Corning researcher Prantik Mazumder, co-author of a paper on the study.
That paper was recently published in the journal Communications Materials.
Source: ICFO