Fabrics that blow hot and cold on demand

Materials World magazine
,
9 Jul 2020

A new material that can change temperature could be used for clothing, heating and cooling the wearer on demand. The film made of carbon nanotubes (CNT) has combined thermal, electrical and physical properties that have potential for developing the next-generation of smart fabrics, say researchers from North Carolina State University (NC State), USA.

‘Many researchers are trying to develop a material that is non-toxic and inexpensive, but at the same time is efficient at heating and cooling,’ says Tushar Ghosh, Professor of Textiles at NC State’s Wilson College of Textiles. ‘CNTs, if used appropriately, are safe, and we are using a form that happens to be inexpensive, relatively speaking. So it’s potentially a more affordable thermoelectric material that could be used next to the skin.’

‘Instead of heating or cooling a whole dwelling or space, you would heat or cool the personal space around the body,’ Ghosh notes. ‘If we could get the thermostat down a degree or two, that could save a tremendous amount of energy.’

The team explains that the properties of CNTs allows heat to be drawn away from the body when applying an external current. ‘Think of it like a film, with cooling properties on one side of it and heating on the other,’ Ghosh says.

Kony Chatterjee, a PhD student at NC State, adds, ‘We want to integrate this material into the fabric itself. Right now, the research into clothing that can regulate temperature focuses heavily on integrating rigid materials into fabrics, and commercial wearable thermoelectric devices on the market aren’t flexible either.’

The team has discovered that the material has a low thermal conductivity, which prevents heat from travelling back to the body once it has been released – this allows for cooling. To warm the wearer, heat can travel towards the body via a current, preventing it from being released into the atmosphere.

The team will continue to develop the smart garment, with the goal of energy harvesting as well as heating and cooling. This could help reduce energy consumption in the future.