Wednesday, April 11, 2007

'Flexible' plastic for electronic circuits?

April 11th, 2007 ‘Flexible’ plastic for electronic circuits?Posted by Roland Piquepaille @ 9:39 am Categories: By adding a polymer acid to a common plastic, chemists at the University of Texas at Austin have developed a plastic with changeable conductivity which could be used to build future electronic devices. This 'doped' plastic can be manufactured at room temperature and can have a conductivity ten times higher than the 'non-doped' one. The flexible sheets of plastics obtained in the lab can be printed with wires and interconnects which could be used to design military camouflage that changes colors, foldable electronic displays and medical sensors. This project has been led by Yueh-Lin (Lynn) Loo, an assistant professor of chemical engineering at the University of Texas at Austin, and the members of her research group. Below is a picture of Loo holding a pliable sheet with printed polyaniline wires and interconnects (Credit: Caroling Lee, University of Texas at Austin). Here are two links to a larger version of this photo and to a page containing several other pictures. Here are some more details about this 'doped' plastic. By combining polyaniline [also known as PANI,] with a chemical that gives it conductivity, Loo discovered she could increase the plastic's conductivity one- to six-fold based on the version of the chemical added. Chemically altered polyaniline has 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. I'm sure you all want to know what was the special ingredient added to polyaniline (PANI) to increase its conductivity. It's a polymer acid named poly(2-acrylamido-2-methyl-1-propanesulfonic acid), or PAAMPSA. But if I've named this post "PAAMPSA meets PANI," would you have read it? For more information, this research work has been published by the Journal of Materials Chemistry under the name "Improving the Electrical Conductivity of Polymer-Acid-Doped Polyaniline by Controlling the Template Molecular Weight" (Volume 17, Issue 13, Pages 1268-1275, 2007). Here are two links to the abstract and to the full paper (PDF format, 8 pages, 392 KB). You also may want to read a previous news release about Loo's work, "Putting a charge in plastics" (January 16, 2006), describing how she researches ways to make cheap, flexible electronic devices. Sources: University of Texas at Austin news release, April 9, 2007; and various websites