Chen Gen: What Kind Of Subversion Will Intelligent Textiles With Shape Memory Bring?

We know that even if the hair has been carefully straightened at high temperature, it will still curl when it comes to water. This is because the shape memory of hair, that is, the material properties of hair, enables it to change its shape under certain stimuli and return to its original shape under other stimuli.

Inspired by this, the researchers turned to other materials, such as textiles. One promising idea about textile shape memory is that a T-shirt, which opens in wet conditions and closes when it's dry, can stretch to the size of a person, which also means it will be a suit for all.

Now, researchers at Harvard University have developed a biocompatible material that can be printed into any shape in 3D and pre programmed with reversible shape memory.

The material is made from keratin, a fibrin found in hair, nails and shells. From the view of molecular structure, the single chain of keratin is arranged into a spring like structure, which is called α helix. It is the α helix structure and the chemical bonds connected that give the material strength and shape memory ability.

In addition, two chains of keratin are twisted together to form a structure called helix. Many of these coils are assembled into filaments, which eventually form large fibers. When a particular sheet is stretched or rearranged, the fibers are stretched into a stable structure. The fiber remains in this position until it is triggered back into its original shape.

To demonstrate this process, researchers 3D printed various shapes of keratin tablets. They used hydrogen peroxide and sodium phosphate solutions to program the material's permanent shape - it always returns to its original shape when triggered. In addition, once the shape memory of keratin is set, it can be reprogrammed and molded into a new shape.

For example, a piece of keratin is folded into a complex origami star as its permanent shape. Once the memory is established, the researchers immerse the star in water, where it unfolds and becomes plastic.

The researchers envision some interesting uses for this new deformable material. They believe the material could be used to make bras in customizable shapes and cup sizes, one size T-shirts, or clothes with vents that can be opened according to moisture. In this way, the researchers hope it will help solve the problem of waste in the fashion industry.

The study was published in the journal natural materials.