Clothes That Clean Themselves!

By Alida Cataldo

Want to wear that filthy T-shirt again tomorrow? No problem! Just hang it in the sun, and it’ll be stain- and odor-free in just a few hours!

Scientists in China have discovered that coating cotton fabric with titanium dioxide -- along with silver iodide -- causes sunlight to remove stains and kill the bacteria that causes odors.

Titanium dioxide (TiO2) is a photocatalyst that triggers chemical reactions in light and is commonly used in sunscreens. Its bright white pigment is used as a dye in paints, soaps, tattoo inks, cosmetics and even food. It can also be found in the rubber, plastics, textiles and paper industries; and it’s been used to create self-cleaning tile, glass and even fabrics before now. In fact for 40 years, many have known that titanium dioxide could remove fabric stains. But until now, it was effective only in ultraviolet light. This new discovery adds nitrogen ions and silver iodide nanoparticles to clean fabric in any natural light and boost cleaning power by about seven times.

But there’s more work to be done before we’re all wearing cotton that cleans itself. Studies have indicated that titanium dioxide powder irritates airways, so it’s recommended that anyone working with it wear a respirator. Also, the World Health Organization is warning that there is “sufficient evidence that titanium dioxide is carcinogenic in experimental animals.” Before this treated self-cleaning cotton is used for clothing, scientists need to do a bit more experimenting to ensure that it’s safe.

Classroom Discussion

• Do you think that self-cleaning clothes will be popular? Why or why not?
• What other materials, besides cotton, might be made self-cleaning?