Most materials get thinner when stretched. Take a rubber band, stretch it along its length, and it will shrink in the other two directions, getting narrower and thinner as you pull. But there are types of materials known as ‘auxetics’ that do the opposite: getting thicker when stretched. Human tendons, cat skin and certain types of metal are examples of natural auxetics, which form tiny voids when stretched, lowering the overall density of the material.

Recently, however, a PhD student at the University of Leeds, UK, discovered a new type of auxetic that displays auxetic behaviour at the molecular scale. Watch the video to find out why this liquid-crystal elastomer (LCE) could be more durable than existing auxetics, making it suitable for body armour, car windows and solar cells. For a more detailed scientific description of this new material, read this feature by Helen Gleeson, the physicist who supervised this research.