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Summary Efforts to create self-cleaning cotton fabrics are bearing fruit in China.
Engineers have created a chemical coating that causes cotton materials to clean themselves of stains and remove odours when exposed to sunlight, a media report said.The researchers say the treatment is cheap, non-toxic and ecologically friendly.Retail experts say the innovation could prove a hit with retailers thanks to a growing demand for functional clothing.The research was carried out by engineers at Shanghai Jiao Tong University and Hubei University for Nationalities, and is published in the latest issue of the Applied Materials and Interfaces journal.The study focuses on titanium dioxide - a chemical known to be an excellent catalyst in the degradation of organic pollutants.The substance is already used in self-cleaning windows, odour-free socks and stay-clean kitchen and bathroom tiles.Initial efforts to extend its use to cotton fabrics proved limiting because the substances self-cleaning properties could only be excited under ultraviolet lights, making it impractical for everyday use.The teams breakthrough was to create a nanoparticle alcohol-based compound made up of titanium dioxide and nitrogen.The mixture was added to triethylamine, an acid neutraliser commonly used in dyes. After being stirred for a 12 hours at room temperature, the liquid was heated at 100C (212F) for a further six hours.The cotton fabrics were then immersed in the mixture before being squeezed dry, heated and immersed in hot clean water.Finally the coated materials were treated with silver iodide particles, which aid light-based reactions.To test the effectiveness of their invention, the engineers marked the fabrics with an orange dye stain and exposed them to the sun. After two hours in the light, the team said 71% of the stain had been removed - a dramatic improvement over previously trialled techniques.
