Carbon Nanotube-Polymer Hybrid Architectures for Flexible Electronics

A team of researchers has developed a new process to make flexible, conducting "nano skins" for a variety of applications, from electronic paper to sensors, for detecting chemical and biological agents. The materials combine the strength and conductivity of carbon nanotubes with the flexibility of traditional polymers.

Nanotube arrays typically don’t maintain their shape when transferred because they are held together by weak forces. But the team has developed a new procedure that allows them to grow an array of nanotubes on a separate platform and then fill the array with a soft polymer. When the polymer hardens, it is essentially peeled back from the platform, leaving a flexible skin with organized arrays of nanotubes embedded throughout.
The skins can be bent, flexed, and rolled up like a scroll, all while maintaining their ability to conduct electricity, which makes them ideal materials for electronic paper and other flexible electronics.

The team has shown that the flexible materials demonstrate an extremely useful physical property called "field emission." When a voltage is applied to certain materials, electrons are pulled out from the surface, which can be used to produce high-resolution electronic displays.

According to the research team, nanotubes are very good field emitters because they have a low threshold for emission and they produce high current; however, when you lay nanotubes very close to each other, each tube tends to shield its neighbor from the electric field. This effect has limited the development of field emission devices based on densely packed, aligned nanotubes, but it seems to go away when the nanotubes are embedded in a polymer. Tests showed that the team’s nano skins are excellent field emitters when compared to some of the best values obtained by other research groups.

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