Moistened with a little water, the flat plastic films fold into pyramids, balls or cubes. Photo: José Bico / APS
Read out French scientists have developed plastic films that fold when moistening themselves to one to two millimeters large pyramids or cubes. The process could be used in the mass production of microelectronic devices, the team hopes to José Bico from the College of Industrial Physics and Chemistry in Paris. The researchers made plastic films in various shapes with a diameter of a few millimeters and drizzled them with water. The water spreads out within a few thousandths of a millimeter thick film and evaporates. As the volume of the water decreases, a surface tension is created. In this way, the film contracts and automatically folds into a three-dimensional figure. This is how a flower turns into a sphere, a previously flat cross becomes a cube and a triangle turns into a pyramid. The size and thickness of the piece of plastic influence how much the film collapses. By heat, the resulting form can be fixed, explain the researchers.

Complex three-dimensional objects are needed for a wide range of microelectronic applications, such as printer heads or medical instrument sensors. However, most production techniques are geared towards the manufacture of flat components. The new origami technique now makes it possible to produce three-dimensional elements in large quantities, the scientists hope.

New Scientist, online service Original text: Charlotte Py (Ecole Polytechnique, Palaiseau cedex) et al .: Physical Review Letters, Vol. 98, No. 15 ddp / science.de? Claudia Hilbert

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