Next winter keeping your toes warm may be just a matter of plugging in your socks.
By Kim Griggs
in Wellington, New Zealand
A "smart wool" that can be heated has been developed by a New Zealand-based company, Canesis Network, in conjunction with an Australian woolgrowers' company, Australian Wool Innovation.
Special conductive fibres in the sock provide a safe, gentle heat
It works by using a conductive fibre which is blended with ordinary wool.
When the "smart" woollen yarn is knitted together, it creates a bed of interconnected fibres with enough resistance to be heated, while retaining all the properties of wool.
"We think that the technology we have here is the first time it's really been integrated into the textile," said Stewart Collie, science manager at Canesis's Smart Textile Innovation Centre.
The first product, socks that can be heated, should be on the UK market by early next year.
The socks are warmed by a small battery, similar to those used in mobile phones.
The batteries would either be attached directly to the sock, or if it was being used for sports such as skiing, the battery might be in the boot.
Linking this pad of smart wool in the socks to a battery will be a highly conductive thread.
The socks would be heated for about three to four hours.
"You'll only get heating for as long as you have it connected to the battery and switched on," Mr Collie told BBC News Online.
"But I think it's likely that people will use these sorts of things intermittently because you often only need to get warm and then the insulation properties of the sock itself and the shoe will help you retain that heat."
The low voltage battery means that the socks would be perfectly safe even if they become damp. The only downside from wet feet may be a drop in the socks' heating power.
"What we need to ensure is that the heating performance doesn't deteriorate, so that if the system gets wet with perspiration or whatever else, it doesn't fail," said Mr Collie.
Cosy in bed
As well as hot socks, Canesis and Australian Wool Innovation (AWI) intend to release a heated blanket.
"Again there are no metal wires in the product so it's got all the drape of a conventional quilt. It will have some discreet cables coming out of the bottom and running off to control units and power supplies which would then plug into the wool socket," said Mr Collie.
The temperature of heated blankets can be controlled
AWI is also looking at incorporating the smart wool into a duvet cover or inner, said Stuart McCullough, a manager of product commercialisation at the company.
"By simply having that element in there, we could recover some of that market that wool has lost to duvets," he said.
The Australasian companies have teamed up with an as-yet unnamed UK retailer to sell the hot socks.
The initial target markets are likely to be outdoor sports such as skiing, hiking, or people, such as parents, who spend hours watching kids' sports.
Canesis, which produced a jacket with controls for a mini-disk player incorporated in its sleeve a couple of years ago, is also planning other intelligent textiles.
Under way are fabrics that glow when you apply an electric charge to them.
Would you buy a carpet that can change colour?
"It can have a pattern or a safety stripe integrated into the fabric that lights up," said Mr Collie.
They are also working on developing textiles that respond to the environment.
"It could become thicker to provide more insulation or become more porous and more open which provides ventilation," said Mr Collie.
"There's a lot of potential for truly intelligent textiles," he added.