José Bico and colleagues at the Ecole Supérieure de Physique et de Chimie Industrielles (ESPCI), in Paris, together with a team from the Paris Institute of Technology have shown that water droplets can be used to make flat shapes fold up to create more complex 3D structures.
Tiny pyramids, boxes and spheres are created when water is added to flat plastic shapes just a couple of millimeters across, with no human intervention whatsoever. As a droplet evaporates, its volume changes while the surface tension holding it to the sheet remains the same. This pulls the shape into a more complex 3D structure.
You want a sphere to appear? No problem, take a flower-like pattern add a drop of water, and the flat sheet will contract and rise to become a small ball, as the water evaporates. Similarly, a triangle becomes a tetrahedron (geometrical shape composed of four triangular faces), and a cross shape folds into a cube.
All of this, right before your eyes, though you will need a small magnifying glass to see the show, as the sheets are only 1 mm long and without the need to master the complex art of origami (the Japanese art of paper folding to create three dimensional objects).
Image: José Bico/APS
Tags: Origami | Plastic Sheets | Water