Watching paint dry isn’t everyone’s idea of fun, but for University College London researcher Yao Lu, the super water repellant properties of this paint could lead to new tough, self-cleaning surfaces. Yao says the chemistry was inspired by nature, such as the water repelling properties of lotus leaves “I am quite interested in self-cleaning coatings in nature, such as plants. We put water on superhydrophobic plants, water wouldn’t wet them. Instead, the water will form drops and then roll off or just bounce away and leave the surface dry and clean.” Superhydrophobic surfaces aren’t anything new, but the researchers at UCL have devised a way to make them extra tough. Professor of Inorganic Chemistry Claire Carmalt says adding an adhesive renders the paint effective even after being scratched, scuffed or exposed to oil. “I think the improvement is the fact that we get this very resistant coating, so generally these superhydrophobic coatings are very mechanically weak, so can be easily rubbed off over time, whereas by applying this spray adhesive we’ve managed to get very resistant coatings that are resistant to, as I say, rubbing or scratching and with sandpaper and so on.” The surface of the paint is rough, rather than smooth, thanks to two different sizes of titanium dioxide nanoparticles. Adding a hydrophobic chemical called fluorosilicate makes the surface waxy. The effect is that water forms near spherical droplets that pick up dirt as they roll off – acting like a miniature vacuum. Such a paint could be applied to a variety of surfaces; including clothes, paper, glass, and steel. The team says it could easily be scaled up for industrial use, such as a paint for cars. The self-cleaning properties, they say, could even be used in antimicrobial coatings to combat hospital infections.