Hydrophobic clothing that won’t stain when you spill something on yourself is the dream of clumsy people everywhere, but the materials that are commercially available generally wear out after a wash or two. Now researchers have come up with a self-cleaning coating that’s tough, even when it gets damaged.
“Commercial hydrophobic surfaces aren’t that robust,” Yao Lu, lead author of the study, tells Popular Science. He says the materials are expensive and don’t last for very long before they become ineffective. As an alternative, Lu’s team worked with titanium dioxide nanoparticles, a material also found in sunscreen. It’s cheap and easily accessible for labs. In a study published today in the journal Science, the researchers tested the coating not only for how well it kept itself clean, but also how it handled contact with oil and damage.
To test it out, the team sprayed the nano coating onto steel, glass, cotton wool, and filter paper, and measured how well those things resisted water compared to untreated materials. Then the researchers assaulted the materials with a battery of tests, covering the surfaces with oil and dirt, even scratching it with sandpaper and knives. But the water-repelling material maintained its self-cleaning properties despite all that. The results were much more promising than most commercial self-cleaning surfaces, which often become impaired when contaminated or damaged.
Lu hopes the coating will be useful on a variety of surfaces, including fabric and even paper to make artistic designs.
Scientists have been working to develop self-cleaning surfaces for years, and have made everything from laser-blasted metals to commercial products such as NeverWet. The advantage the titanium dioxide nanoparticle coating has over other hydrophobic products is how durable and inexpensive it is.
But what’s even cooler than that is how it looks when it comes in contact with water. Watch it react to all different kinds of surfaces–it’s pretty mesmerizing: