Researchers at Leiden and Harvard University found that corrugated plastic is an example of a new class of multistable metamaterials that can reversibly change shape.

The discovery involves sheets of corrugated plastic, or other materials that contain corrugations or grooves. When the sheet is pulled, the grooves buckle and form an extended ridge perpendicular to the grooves. This ridge will stay in place even if you stop pulling and forces the sheet into a new shape. Combining various ridges can result in stable rolls, spirals, and helical shapes. When you pull the sheet even further apart, the ridges disappear, and it is possible to reshape the material.

This process happens because each buckled groove acts as a defect. The defects repel each other, until they are brought too close, then they stick together and lock into place as a ridge.

The newly discovered principles of multistability and shapeshifting materials open up many different types of applications, such as foldable emergency housing, and even robot parts that can easily switch back and forth between programable shapes are feasible.

Photo: Leiden University