Plastic that conducts electricity
By placing a thin film of metal onto a plastic sheet and mixing it into the polymer surface with an ion beam, an international team has shown that the method can be used to make cheap, strong, flexible and conductive plastic films.
"What the team has been able to do here is use an ion beam to tune the properties of a plastic film so that it conducts electricity like the metals used in the electrical wires themselves, and even to act as a superconductor and pass electric current without resistance if cooled to low enough temperature," Prof Paul Meredith of University of Queensland, who led the team, said.
To demonstrate a potential application of this new material, the team produced electrical resistance thermometers that meet industrial standards. Tested against an industry standard platinum resistance thermometer, it had comparable or even superior accuracy.
"This material is so interesting because we can take all the desirable aspects of polymers — such as mechanical flexibility, robustness and low cost — and into the mix add good electrical conductivity, something not normally associated with plastics It opens new avenues to making plastic electronics," Prof Adam Micolich of University of New South Wales, a team member, said.
Team member Andrew Stephenson said the most exciting part about the discovery is how precisely the film`s ability to conduct or resist the flow of electrical current can be tuned.
It opens up a broad potential for useful applications.
"In fact, we can vary the electrical resistivity over 10 orders of magnitude — put simply, that means we have ten billion options to adjust the recipe when we`re making the plastic film. In theory, we can make plastics that conduct no electricity at all or as well as metals do — and everything in between," he said.
These new materials can be easily produced with equipment commonly used in the microelectronics industry and are vastly more tolerant of exposure to oxygen compared to standard semiconducting polymers.
Combined, these advantages may give ion beam processed polymer films a bright future in the on-going development of soft materials for plastic electronics applications – a fusion between current and nextgen technology, say scientists.
The findings have been published in the latest edition of the `ChemPhysChem` journal.