Bruisable gadgets heal themselves in the sun

GADGETS of the future could bruise when dropped or scratched to highlight damaged areas. Don’t worry though, as a few minutes in the sun will be enough to fade the bruise and repair the damage. Marek Urban and colleagues at the University of Southern Mississippi in Hattiesburg were inspired to create their self-healing plastic by signs of healing in nature such as newly formed tree bark. 
Earlier self-healing materialsMovie Camera do not change colour and require focused laser light for repairs. This new material turns red when damaged and repairs itself when exposed to visible light or changes in temperature or pH. It can also fix itself multiple times, unlike previous materials. 

Like all plastics the new material contains long chains of polymers, except that the chains are linked by small molecular bridges that break and change the plastic’s shape when it is scratched. This shape-change produces the bruise, which disappears when energy from the light enables the bridges to reform and the plastic to heal. Urban, who presented the research at a meeting of the American Chemical Society in San Diego, California, last week, says the new material is not expensive. "It could be used anywhere really, the sky is the limit."