Published: 01 Sep 2004 18:25 BST
Researchers warm to magnetic plastic
The world’s first practical plastic magnet has been created at the University of Durham, according to a report in New Scientist magazine.
After three months of mostly fruitless experiments, researchers began to detect magnetism in the mixture of two plastic polymers and the compound has now passed its first real test: it can pick up iron filings.
Although magnetic plastics have been reported before, they have only worked at extremely low temperatures. The Durham compound, made out of a conductive plastic called emeraldine base polyaniline (PANi) and a free radical generator called tetracyanoquinodimethane, is active at room temperatures.
Researcher Naveed Zaidi told the magazine that although the compound is as yet weakly magnetic there is much room for improvement. “The reaction is not yet 100 percent efficient along the polymer and the strength of effect varies throughout the material. Once we increase this efficiency, this overall strength will certainly increase,” said Zaidi.
Future uses of the plastic could include coatings for computer hard disks as well as roles in medical implants, as the body is much more tolerant of plastic than metal. PANi has been under investigation by a number of institutions because of its conductive properties: it has been shown to act as a light emitting diode and to have potential uses in infrared optics. It’s also used in fuel cells, and is a member of a larger class of conductive plastics that are beginning to be used in industry.
However, there remains a great deal of work to do before any practical application for the magnetic variant is found, according to material scientist Jerry Torrance. He told New Scientist that the discovery was nevertheless “a significant scientific breakthrough”.