A team at City University has developed a self-cleaning cashmere that uses energy from the sun.
The technology coats cashmere fibres with tiny particles that help break down bacteria, dirt and even coffee and wine stains.
"Within 24 hours of daylight exposure, any red wine or coffee stains were gone," said Walid Daoud, assistant professor in City University's school of energy and environment and the lead researcher on the project.
Daoud and other researchers have applied a coating of the mineral anatase titanium dioxide to cotton and wool since 2002, but this is the first time the technology has been applied to cashmere, a fabric that is notoriously expensive to clean.
Daoud said retaining the softness of the fabric and preventing damage to the delicate fibres from the oxidisation process was a "huge challenge".
If commercialised, the process could lead to substantial savings on energy, water, washing liquids and dry cleaning chemicals, he said.
The price of the treatment would only increase the cost of production by 1 or 1.5 per cent, Daoud said. He said washing and dry-cleaning would not remove the coating from fibres, but the fabric had yet to be exposed to steam cleaning or ironing.
Anatase titanium dioxide is not on the list of materials restricted by the US, according to Tommy Siu Yuk-yinn, senior research and development manager with TAL, a major clothing manufacturer in Hong Kong that supplies the US market.
The company has been dealing with researchers at the Hong Kong Polytechnic University, Daoud's former employer, about similar technology for its clothing, but has yet to adopt it.
"I think 24 hours is still too long," Siu said. "We don't have 24 hours of sunlight in a day. Also, is it OK if it's diffused sunlight? We don't always have direct sunlight.
"We also have to think about whether sunlight would discolour fabric."