Down the Line: New Plastic Conducts Electricity
Researchers have developed a new plastic that conducts electricity, may be simpler to manufacture than alternatives and easily accommodates chemical attachments to create new materials.
Oligotron polymers are made of tiny bits of material that possess a conducting center and two nonconducting end pieces. The end pieces allow the plastic bits to dissolve in solvents and accommodate specialized molecules.
With support from the National Science Foundation (NSF, Arlington, VA), engineers at TDA Research Inc. (Wheat Ridge, CO) developed a water-soluble conducting polymer that contains polyethylenedioxythiophene (PEDOT). Oligotron is soluble in noncorrosive chemicals and can attach new compounds to its end pieces, adding a variety of functions. For example, researchers have proposed end pieces that convert solar energy into electricity, ultimately creating a novel solar cell material.
"We discovered that by attaching molecules to the ends of the PEDOT, the chemical could easily disperse in organic solvents, something we have not seen with typical conducting polymers," says Brian Elliott, senior chemical engineer. "When we added photo-sensitive end groups to the Oligotron, we created a material that could be printed using an ultraviolet light source. Using a patterned light source resulted in a patterned image that could conduct electricity.
"The reactive chemical groups on the ends of the Oligotron molecules will allow other scientists to synthesize new molecules, building additional functionality onto the molecule," claims Elliott. "These molecules will allow chemists to use their creativity to invent new materials with conducting polymers."
"This is a significant breakthrough," claims Winslow Sargeant, NSF program officer. "A soluble and highly conductive multi-block copolymer, with its ability to be photo-crosslinked, could lead to a printable conducting polymer with a high conductivity."
In addition to the potential savings in weight and cost, Sargeant says conducting polymers could be manufactured in a variety of convenient shapes, yielding such innovations as smart fabrics that transmit data. Commercial applications for the product range from paper-thin television displays and smart cards to antistatic treatments and conducting fabrics.
"Flat-panel displays are probably the largest market for organic electronic materials," says Sargeant. "The development of soluble polymers could have a large impact on the cost and ease of processing these displays."
Oligotron also has special properties that allow the material to be "printed" into various device shapes. When engineers shine a pattern of ultraviolet light, such as a complex circuit image, onto a film of dissolved Oligotron, the exposed areas of plastic become fixed like a photograph. Flexible and lightweight, the circuit is also fully functional.