Scientists in the Netherlands and United States have developed a new polymer that can undulate and move itself forward under the influence of light. Elly Park reports.
This caterpillar-like device is actually a new polymer material that can "walk" under the influence of light. Developed by scientists at Eindhoven University of Technology in the Netherlands, it's a special type of plastic made of a liquid crystalline polymer commonly used in LCD displays. Motion is created by one side contracting in reaction to light, while the other side expands inside its rectangular plastic frame, explains co-lead author Anne Hélène Gélébart. SOUNDBITE (English) ANNE HÉLÈNE GÉLÉBART, CO-LEAD AUTHOR, EINDHOVEN UNIVERSITY OF TECHNOLOGY, SAYING: "There are a few key parameters. The first one is to have a molecule that can relax fast, so that the deformation can be....the film can be deformed in one way but relaxed to the initial position as soon as the light goes on and off. Second parameter that is really crucial is the self-shadowing. To obtain that we made this pre-curved shape, so that when the light comes onto the film it will illuminate one part. But the other one will be in shadow." The material looks transparent to the human eye, but fully absorbs the ultra-violet light used, creating this shadow. The polymer can move at about half a centimeter per second, similar to the speed of a real caterpillar. Co-author Dirk Jan Mulder says the material can worm its way into everyday use. SOUNDBITE (English) DIRK JAN MULDER, CO-LEAD AUTHOR, EINDHOVEN UNIVERSITY OF TECHNOLOGY, SAYING: "If we apply this material on solar panels in the desert, if a sandstorm comes there the panels are fouled and it's very difficult to get all the sand off or somebody has to go there and clean it. This material, with the sunlight maybe even, is able to vibrate and get rid of the sand." Another application could be in small robots that crawl by themselves into narrow spaces, directed by light, moving small items in hard-to-reach places.