New "Chameleon" material has been created – the chemical industry

Posted by Admin on Jul 1, 2010 in Articles | 0 comments

Fudan University researchers for the first time the environment-sensitive polymers, two acetylene and carbon nanotube composite fibers formed, with the development of a new type of electrochromic smart materials, composite fibers by electrical stimulation of the rapid change or restore the color. This new type of “chameleon” materials are expected in the military field, aerospace, optoelectronics and other fields have important applications. The research results were published in the September 13 world-class academic journals “Nature? Nano-technology”.

Biological systems with the environmental changes will automatically control the structure and function, such as the chameleon in different environmental conditions showed powder, blue, red, orange, green, black, brown, yellow and other colors. How to simulate chameleon-sensitive material has been synthesized scientific research hot spots, the most current research for a class-sensitive material?? Together two acetylene, in the heat, ions, Chemical Reagent , Mechanical stimulation of the role of rapid change in color, color mechanism for the conformational change to external stimuli, resulting in changes of conjugated chain length, due to conjugate Electronic Transitions occur in different energy absorbed, resulting in color change directions. Although the poly diacetylene can change the color by stimuli, but because poly diacetylene very low conductivity, not by a small current to stimulate the poly 2-acetylene conformation changes color, can not allow current to stimulate the color poly diacetylene environmental factors that greatly stimulate the color limited; other poly diacetylene as generated by the stimulation is often irreversible color change, but also makes the practical application of diacetylene polymer is very narrow.

Department of Macromolecular Science, Fudan University Molecular Engineering of Polymers Education Ministry Key Laboratory of Advanced Materials Laboratory, the research team headed by Professor Peng Huisheng since the beginning of 2008 will be dedicated to research on carbon nanotubes, in one experiment, the researchers will join a polymer of carbon nanotubes, actually happened wonderful color change, inspired by this, the research group began testing the polymers such as poly diacetylene connection with carbon nanotubes.

Layer carbon nanotube is a graphite rolled into seamless, hollow tube, due to the unique chemical structure, room temperature conductivity as high as 104S/cm. Peng Huisheng discussion group through chemical reaction or physical interaction to gather diyne connected to the surface of carbon nanotubes, which were prepared with good electrical conductivity properties of poly 2-acetylene / carbon nanotube composite fibers. Experiments show that when the load current exceeds the critical value, the composite fibers can occur within two seconds, the color changes; unloaded current at the color of the fiber in two seconds, then resume as before, make up the poly 2 acetylene color change is irreversible defects, using the means of electrical stimulation that makes the material a much broader application. The composite fiber is suitable for mass production, with industrial prospects. Related technology has a number of international and domestic patent applications.

And ordinary Chemical fiber Similarly, poly 2-acetylene / carbon nanotube composite fibers can be easily woven into the actual needs of the structure of various shapes, can be applied to a very wide range of areas. The researchers said electrochromic and mechanical discoloration of sensitive materials may be color devices, smart windows, sensitive devices and memory devices, and other field applications. Perhaps in the near future, according to their mood to the walls of houses to transform arbitrary color can be possible.

“Natural? Nanotechnology” magazine reviewer commented, “… … the research results represent an important area of composite materials, progress in the application of sensitive devices is important. These results are in materials science , electronic engineering, chemical engineering and other fields have wide interest. ”

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