Mingce Long and Deyong Wu, material scientists at Donghua University of China, have developed a special fabric that rids itself of dirt and bacteria when exposed to sunlight. According to a report at www.textile.com, they have done it by dunking cotton into a vat of specially crafted nanoparticles.
The chemistry behind the self-cleaning fabric is titanium dioxide (titania), an inexpensive, nontoxic powder used in white paint, and silver iodide, a photosensitive chemical used in film photography. Titanium dioxide absorbs ultraviolet light and oxidizes organic compounds and silver iodide darkens with exposure to light.
Scientists had previously shown that titanium dioxide mixtures could remove stains from clothes, but it requires exposure to ultraviolet light; silver iodide can speed up the chemical reactions in sunlight. The fabric coating is insoluble in water and can repeatedly break down dirt and stains.
The self-cleaning cotton is not marketable yet, and still needs testing to assure the coated cotton won’t harm wearers. Silver iodide is toxic when ingested and repeated contact with skin can turn the skin blue. Titanium dioxide also can cause health problems if it gets in the lungs.
Viable manufacturing costs are still to be determined, also.