Origami-shaped conducting polymer stretches like an accordion
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nm to 498 nm. The photocatalytic activity in the presence of PS/SnO2 foam results in 98.2% degradation of RhB. The porous structures of the nanofoams offer more active catalytic sites due to the favorable reaction of OH radicals on the foam surface, and the dye molecules enable efficient degradation. Furthermore, the foam from the waste material can be reused up to four times without compromising the photocatalytic activity. However, loss of efficiency is observed with the fifth cycle. “As this work has established the proof of principle, we are now looking for more
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stable systems such as polymer/gold, from the catalytic point of view,” Oliveira says. Hicham Idriss, a research fellow at the Saudi Basic Industries Corporation (SABIC), appreciates the study. “The article deals with using styrene foam (commonly called Styrofoam) as support for a wide-bandgap semiconductor for dye degradation. The work is sound and convincing. However, the wide-bandgap semiconductor used, SnO2, is only active under UV, making its potential for application very limited,” he says. Rahim Munir
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Origami-shaped conducting polymer stretches like an accordion
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group of researchers from University at Buffalo, The State University of New York and Temple University has developed a material that is both electrically conductive and can stretch like an accordion, as published in a recent issue of Advanced Materials (doi:10.1002/adma.201706390). The material introduced by Ying-Shi Guan and co-workers is a combination of a stretchy polymer, termed TFB (poly[(9,9dioctylfluorenyl-2,7-diyl)-co-(4,4′(N-(4-sec-butylphenyl)diphenylamine)]), and a conductive polymer, termed P3BT (poly(3-butylthiophene-2,5-diyl)), together known as PthTFB. This hybrid material by itself is not sufficient for wearable electronics, but the implementation of three advances allows this material to gain the desired properties. The first is a technique that allows the polymer molecules to self-assemble into a very flat and very uniform film, with a minimum thickness of ≈12 nm. This was achieved by dropping the solution of polymer molecules onto the surface of water, where the Marangoni effect (also responsible for causing wine to flow up the sides of glasses) stretches the droplet into a film. This thin film can be deposited on a surface and is moderately stretchable and weakly conductive. However, it becomes less conductive the more it is stretched. The second advance exploited the geometry of a type of origami called
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A kirigami polymer film (a) before and (b) after being stretched, as part of a circuit that lights an LED. Credit: Advanced Materials.
kirigami (Japanese for cut paper), which produces structures that can fold compactly and stretch immensely. The film by itself can stretch by an extra 15% of its length before breaking, and it becomes less conductive in the process. After the PthTBF is deposited on kirigami-cut paper, the film can be stretched by 2000% (20 times its length) without breaking, and it still conducts electricity just as well. The conductiv
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