Imagine not needing a new coat for every season, but having a jacket that dynamically changes shape to better insulate and keep warm when temperatures drop.

A programmable fibre developed by an interdisciplinary team of MIT researchers could make this vision a reality. Called FibeRobo, the fibre contracts at higher temperatures and expands when it gets colder. All without embedded sensors or other solid components.

The low-cost fibre is fully compatible with textile manufacturing techniques and can be produced continuously per kilometre. This could allow designers to add actuation and sensing capabilities to a wide range of fabrics for myriad applications.

The fibres can also be combined with a conductive thread that acts as a heating element when electric current flows through it. In this way, the fibres are activated by electricity, giving the user digital control over the shape of a textile. For example, a fabric could change its shape based on digital information, such as readings from a heart rate sensor.

Adaptable sports bra

The researchers around MIT PhD student Jack Forman used FibeRobo to demonstrate several applications. These included an adaptive sports bra that tightens when the wearer starts exercising.

They also made a compression jacket for Forman's dog. The jacket is activated via a Bluetooth signal from Forman's smartphone and "hugs" the dog. Compression jackets are commonly used to relieve a dog's separation anxiety when its owner is away from home.

In the future, researchers hope to adapt the chemical components of the fibre to make it recyclable or biodegradable.