- Title: First 'walking' polymer revealed
- Date: 7th August 2017
- Summary: EINDHOVEN, NETHERLANDS (JULY 4, 2017) (REUTERS) (SOUNDBITE) (English) DIRK JAN MULDER, CO-LEAD AUTHOR, EINDHOVEN UNIVERSITY OF TECHNOLOGY, SAYING: "What we use is a special type of plastic. It's made of a liquid crystalline polymer, which means that the compounds in there are like liquid crystals that we see in displays nowadays, and they have a certain order in them. This order that's the part that we use to get this deformation going, but only with the plastic the deformation is not necessarily light responsive, so we also added in this polymer a light responsive compound." MULDER AND FELLOW LEAD AUTHOR ANNE HELENE GELEBART WALK INTO LABORATORY AND PUT ON INFRA-RED SAFETY GOGGLES MULDER AND GELEBART SET UP EXPERIMENT WALKING POLYMER STRIP (SOUNDBITE) (English) ANNE HELENE GELEBART, 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, which means that as soon as the light goes on that one it deforms, put another piece of the film in the light, that will deform, and so on and so on." GELEBART MOVING STRIP WITH TWEEZERS WALKING POLYMER STRIP (SOUNDBITE) (English) ANNE HELENE GELEBART, CO-LEAD AUTHOR, EINDHOVEN UNIVERSITY OF TECHNOLOGY, SAYING: "You need this pre-buckled shape. That's why we also use these tiny plastic frame around, so that you always have this constraint on the film, because let's say if we wouldn't have this plastic frame around and then you put the light on it, it would just make one move and it will eventually end up flat. So this is not what we want, so we really use this plastic frame to really maintain this constraint and that way we can have this undulating motion." VARIOUS OF GELEBART FOCUSING MICROSCOPE GELEBART MOVING STRIP WITH TWEEZERS (SOUNDBITE) (English) ANNE HELENE GELEBART, CO-LEAD AUTHOR, EINDHOVEN UNIVERSITY OF TECHNOLOGY, SAYING: "Photo response has been done before. Here we also really emphasize the fact that it's not only photo, but photo-thermal, so the temperature also plays an important role in this process. What is really new, because for instance we have the group of Timothy White in the US and made this cantilever. They have a tiny surface that can oscillate continuously with direct and fixed input of light, but there is not this directionality, so here what we really implemented is the directionality of the motion while keeping everything fixed, so it's really hands-free and then it moves in one direction." VARIOUS OF WALKING POLYMER STRIP (SOUNDBITE) (English) DIRK JAN MULDER, CO-LEAD AUTHOR, EINDHOVEN UNIVERSITY OF TECHNOLOGY, SAYING: "We were thinking about, for example, solar panels. 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. That's also something we have demonstrated in the paper and we can see that we can eject sand when it's applied to this material."
- Embargoed: 21st August 2017 16:08
- Keywords: Walking polymer Technische Universiteit Eindhoven Light LCD Eindhoven University of Technology TU/e
- Location: EINDHOVEN, NETHERLANDS
- City: EINDHOVEN, NETHERLANDS
- Country: Netherlands
- Topics: Science
- Reuters ID: LVA0026T5R4GR
- Aspect Ratio: 16:9
- Story Text:Researchers say they have developed a new polymer material which can 'walk' when a single fixed light source shines upon it.
Co-lead author Dirk Jan Mulder, of Eindhoven University of Technology (TU/e) told Reuters: "The special type of plastic is made of a liquid crystalline polymer, which means they are built out of compounds like liquid crystals that we see in (LCD) displays. They have a certain order in them which we use to get this deformation going. We added to this polymer a light responsive compound."
Motion is created by one side contracting in reaction to light, while the other side expands inside its rectangular plastic frame, making the wave bulge when illuminated.
The material looks transparent to the human eye, but fully absorbs the ultra-violet light used, creating a shadow behind it.
"What is crucial is the self-shadowing," said co-lead author Anne Helene Gelebart. "We made this pre-curved shape, so that when the light comes onto the film it illuminates one part. The other part will be in shadow. As soon as the light goes on it deforms, placing another piece of the film in the light, and that one deforms, and so on."
The polymer's frame is shorter than the strip itself, causing it to bulge downward, creating a dent in the strip and allowing it to walk. When the frame - the size of a paperclip - is turned upside down the wave travels in the opposite direction, making it walk towards the light.
"This plastic frame maintains this constraint and creates this undulating motion," said Gelebart.
The polymer can move at about half a centimetre per second. Researchers think it could be used as small robotic material that crawls by itself into narrow spaces, directed by light, moving small items in hard-to-reach places.
In tests researchers placed grains of sand on the strip, which were removed by the undulating movement.
"If we apply this material on solar panels in the desert and a sandstorm dirties the panels, this material is able to undulate and get rid of the sand," said Mulder.
The study, carried out by researchers from TU/e and Kent State University, was published in scientific journal Nature in June. - Copyright Holder: REUTERS
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