New plastic material begins to oscillate spontaneously in sunlight

New plastic material begins to oscillate spontaneously in sunlight

Place this thin layer of plastic in the sun and it begins to oscillate irregularly all by itself. Today researchers from Eindhoven University of Technology (TU/e) and the Humboldt University in Berlin present this material – the first that moves spontaneously under the influence of daylight – in the journal Nature Communications. According to the researchers, this pliable plastic is suitable as a self-cleaning surface, for example for solar cells.

Materials that move all by themselves under the influence of light – this phenomenon has been known for a number of years. However, since the source tends to be ultraviolet light, the required intensity can damage the material. The challenge was to find a material that behaves in this way in visible light, preferably unprocessed sunlight. The researchers from Eindhoven and Berlin have now succeeded in producing a thin containing light-sensitive molecules (azo-dyes). Lying in sunlight, the thin film begins to oscillate spontaneously and irregularly.

Combination of factors

Why the plastic does this is something that the researchers cannot yet quite explain. "It seems to be a combination of factors," suggests TU/e researcher Michael Debije. "The -sensitive molecules bend and stretch under the influence of . Since these molecules are bound within the polymer network of crystal, this results in the material oscillating as if cramped. Of course, there's more to it than that – this is what we are investigating now."

Credit: Eindhoven University of Technology
Self-cleaning

One of the main possibilities for using the material is as a self-cleaning surface. "A surface that vibrates in the sun makes it difficult for sand and dust to stick to it," Debije says. Fellow researcher, Dick Broer, thinks that self-cleaning solar panels in the desert where there are no water supplies could be an option. But the researchers believe there is a whole range of other possible applications. "We have just discovered the effect; we expect that this will attract attention from many researchers from whom we will be hearing a lot over the coming period," Debije says.


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More information: Kamlesh Kumar et al., A chaotic self-oscillating sunlight-driven polymer actuator, Nature Communications (4 July 2016). DOI: 10.1038/nscomms11975
Journal information: Nature Communications

Citation: New plastic material begins to oscillate spontaneously in sunlight (2016, July 5) retrieved 26 April 2019 from https://phys.org/news/2016-07-plastic-material-oscillate-spontaneously-sunlight.html
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Jul 05, 2016
I wonder if a device could be created that uses this material to convert the movement into electrical energy, offering another way of generating electricity from sunlight. I suspect the power will be too low, but I don't know.

Jul 05, 2016
Id be curious to see at what scale this effect stops working. That might lead to a better understanding of is uses.

Jul 05, 2016
I wonder if a device could be created that uses this material to convert the movement into electrical energy, offering another way of generating electricity from sunlight. I suspect the power will be too low, but I don't know.

I imagine it would depend on oscillation frequency and, of course, intensity.
Id be curious to see at what scale this effect stops working. That might lead to a better understanding of is uses.

Or starts.
This article seemed more like a "fishing" trip to gauge potential future interest...


Jul 05, 2016
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Jul 05, 2016
It's a gel, and gels have phase transitions. Same concept behind the muscle and every other living tissue in the human body. See the work of Dr. Gerald Pollack of the University of Washington.

Regardless, use as a viable mechanical power source still depends on frequency and strength of oscillation.

Jul 06, 2016
@ForFreeMinds --exactly what I was thinking; maybe something like millions of hair units with rigid anchor points and piezo bridges all assembled onto a conductive substrate like a sheet of velvet.

Jul 06, 2016
I wonder if a device could be created that uses this material to convert the movement into electrical energy

Easily. Put some magnetic material on the edge and put it in a coil.
However ,just plastering the same area with a solar cell is more efficient.

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