Self-cleaning surfaces could be used for smartphone screens

A team from the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB are investigating the use of titanium-dioxide molecules incorporated into the surface of materials, which gives them self-cleaning properties.

When titanium-dioxide molecules are activated by the Sun’s UV light they act as a catalyst, triggering an electrochemical reaction that produces free radicals (atoms with unpaired electrons).

These and other active molecules have the ability to kill off bacteria, fungi and similar organisms. Initially, they destroy the cell walls and then penetrate the cytoplasm and damage the cell’s DNA. As a result, the organic substances are destroyed instead of remaining stuck to the surface.

‘We ran some outdoor tests on garden-chair armrests with photocatalytic coatings and compared them to ones made from conventional plastics,’ said Dr Iris Trick, group manager at IGB in Stuttgart.

Dr Trick and her team sprayed the coated and uncoated armrests with a mixture of various bacteria, mosses, algae and fungi and then left them exposed to the weather for two years.