A water-resistant paint that can clean itself and withstand contact with oil, even after being scratched with a knife and scuffed with sandpaper, has been developed by British and Chinese researchers.
The coating can be applied to clothes, paper, glass and steel and was devised by University College London (UCL) researcher Yao Lu and his supervisor, Professor of Inorganic Chemistry Claire Carmalt.
The super water repellent properties of this paint could lead to new tough, self-cleaning surfaces, which normally often stop working when they are damaged or exposed to oil. Its self-cleaning properties remain because adhesives were added in the composite.
Claire Carmalt, co-author, said: “The surfaces tend to be mechanically weak and so rub off easily, but by pairing our paint with different adhesives, we’ve shown it is possible to make a robust self-cleaning surface.”
The study, published in Science, showed that the paint made from coated titanium dioxide materials can give a wide range of materials self-cleaning properties. This could lead to paint resistance to everyday wear and tear, and could be used for an array of real-world applications from clothing to cars, the researchers said.
Lu said: “Being waterproof allows materials to self-clean as water forms marble-shaped droplets that roll over the surface, acting like miniature vacuum cleaners picking up dirt, viruses and bacteria along the way.
“For this to happen, the surface must be rough and waxy, so we set out to create these conditions on hard and soft surfaces by designing our own paint and combining it with different adhesives to help the surfaces withstand damage.”
The researchers used different methods and materials to create the waterproof surfaces. For instance, they used an artist’s spray-gun to coat glass and steel, dip-coating for cotton wool and a syringe to apply the paint onto paper.
Once the materials were exposed to water, droplets of different sizes were seen bouncing instead of wetting the surface, removing the dirt applied by the researchers and after damage was inflicted on the surface.
“Car paint frequently gets scuffed and scratched and we wanted to make sure our paint would survive that. As well as practical uses, the paint could also be used creatively to make art with water which is something I have been exploring in my own time,” Lu said.