People who like bathing in the sun could be warned when to take shelter in the shade thanks to a strip of plastic which changes colour just before exposure to too much UV light.
Researchers at Queen’s University Belfast developed an indicator, containing smart ink, which turns colourless from an initial blue to warn you when to stay out of the sun before you burn.
The plastic strip – worn as a bracelet – changes colour at a speed that depends on the wearer’s skin type and can be worn at the same time as sun lotion.
It is based on ‘photocatalysis’, a technology developed by researcher David Hazafy, who was awarded £85,000 as an engineering fellow to allow him to develop the research into products for commercial use.
Photocatalysists work by harvesting energy from ambient sunlight to drive successful chemical reactions, such as destroying bacteria or pollutants and changing the colour of dyes.
Mr Hazafy said: “The sunburn indicator works by using a photocatalyst and a redox dye in which the former absorbs the ultraviolet light and uses its energy to drive the change in the colour of the dye.
“The sunlight, or the total UV component, is collected throughout the day so the user is aware of the total dose of the harmful irradiation received by the band and warned when it nears the level which causes sunburn.
Other photocatalyst-based technologies use the light-driven antibacterial plastic films in a range of materials including hospital curtains, flooring, tiles and glass, to create a more sterile, safer environment.