Ever wished your paper aeroplane would just make itself? Well now it can. Almost. Because scientists have developed a material that can fold itself when you shine light on it, without you ever needing to lay a finger on the thing.
It's actually really simple. You take a sheet of pre-stressed plastic, and then print bold black lines where you want the folds to appear. Trim the piece of plastic into the shape you need, shine an infra-red light on it and — bingo! — your shape folds itself.
The black lines absorb the far more energy from the light than the rest of the plastic, y'see. That means that the plastic under the black parts contracts and forms a fold. So far they've managed to make cubes (check out the video) and pyramids, without ever having to physically touch the material.
No word quite yet on when it will make me a paper aeroplane. But my fingers are crossed. In the meantime, I can at least console myself with these less satisfying, but equally fun, self-folding paper boats. [Soft Matter via EurekAlert!; Image: NCSU]