Plastic with adjustable conductivity

Apr 10, 2007 13:55 GMT  ·  By

Olyaniline (PANI) is a conducting polymer of the semi-flexible rod polymer family, discovered in 1934 as anilin black, that can also exist naturally as part of a mixed copolymer with polyacetylene and polypyrrole in some melanins.

A University of Texas at Austin researcher has modified this special plastic so that its ability to carry an electrical current can be altered during manufacturing to meet the needs of future electronic devices.

Dr. Yueh-Lin (Lynn) Loo, an assistant professor of chemical engineering who has studied the polyaniline said it could serve as flexible, inexpensive wiring in future applications such as military camouflage that changed colors, foldable electronic displays and medical sensors.

Loo discovered that by combining polyaniline with a chemical that gave it conductivity, it was possible to increase the plastic's conductivity one- to six-fold based on the version of the chemical added.

Studies further revealed that chemically altered polyaniline had several advantages over the more commonly used metals, like gold and copper, in devices other than computers.

For example, Loo's previous research has demonstrated that "doped" polyaniline can be manufactured in solution at room temperatures and without vacuum chambers. Producing metal-based wires requires special manufacturing conditions in addition to the high cost of the metals.

One advantage is that their version of polyaniline has a conductivity 10 times higher than before. However, that level of electrical conductivity still doesn't rival that of copper, which is used to produce high-speed interconnections.

"Understanding how the structure of this polyaniline material changes when its conductivity changes will be crucial for selecting the right material for different consumer applications," Loo said, adding that the ability of the plastic to change colors depending on whether it was conductive or not could be especially useful.

"Its general versatility could lead to a variety of new consumer products in upcoming years," she said.