I’m pretty sure that all of my readers have tried, at least once the exquisitely delicious ‘Shauarma’ of Concordia 1 Café and I’m equally sure that you guys must have spilled the juicy contents of ‘Shauarma’ onto your hands or clothes. If that bothers you and makes you feel hesitant while ordering your next Shauarma, then stop worrying. I’ve got interesting news for you guys. How about having clothes, which clean up by themselves when you step out of the café in the sunlight?
Researchers at Monash University, in Victoria, Australia, led by Organic Chemist and Nanomaterials researcher Waleed Dawood, have discovered a way to coat fibers with titanium dioxide nanocrystals, which break down food and dirt in sunlight. They have coated natural fibers such as wool, silk, and hemp so that they will automatically shed food, grime, and even red-wine stains when exposed to sunlight.
Titanium dioxide is used in sunscreens, toothpaste, and paint, and it is a strong photo catalyst. In the presence of water vapor and ultraviolet light, it forms hydroxyl radicals, or decompose organic matter. However, these nanocrystals cannot decompose wool and are harmless to skin. The nanocrystal coating doesn’t change the look or feel of the material.
Titanium dioxide also destroys bacteria in the presence of sunlight by breaking down the cell walls of the microorganisms. Self-cleaning fabrics would be useful in hospitals and other medical settings. The material stands up to red-wine stains, which are very difficult to remove. After 20 hours of exposure to simulated sunlight, titanium-dioxide-coated wool shows almost no sign of the red stain, while the untreated wool remains boldly stained. Other stains disappear faster: coffee stains fade away in two hours, while blue-ink stains disappear in seventeen hours.
Materials that use nanoparticles have been developed in the past. Stain-repellant fabrics and paints that are currently on the market typically have a nanoparticle or nanofiber coating that causes drops of liquid to roll off instead of getting absorbed into the material, taking small particles of dirt and grime with them.
So it is probably right time to say ‘Good bye’ to the old Surf Excel and bring the new type of clothing in vogue.
By Hamza Naveed, Institute of Environmental Science and Engineering.