Conductive plastics discovery could revolutionise micro-electronics

A team of Australian scientists has found a way to print micro-electronics on to flexible plastic film, using equipment already in use throughout the industry.

The team took a flexible plastic sheet and used an ion beam to etch a layer of metal over it, forming circuits to conduct electricity.

The technique is currently used in the micro-electronics industry to add conductivity to silicon, but adapting this to plastics has never been achieved before, despite 20 years of research.

"This opens new avenues to making plastic electronics," said associate professor Adam Micolich of the University of New South Wales School of Physics.

"This material is so interesting because we can take all the desirable aspects of polymers, such as mechanical flexibility, robustness and low cost, and add good electrical conductivity, something not normally associated with plastics."

The team demonstrated the technique by printing electrical resistance thermometers that performed as well, or better, than the industry standard platinum resistance devices used today.

Plastic circuits produced in this way are more tolerant to exposure to air than current silicon technology, the team said, and all of the equipment used to create the plastic circuits is already in operation printing on silicon, so there are few hurdles to large-scale deployment.

"In theory, we can make plastics that conduct no electricity at all, or as well as metals do, and everything in between," said team member Andrew Stephenson.

"In fact, we can vary the electrical resistivity over 10 orders of magnitude. Put simply, that means we have 10 billion options to adjust the recipe when we're making the plastic film."

Plastic is traditionally such a poor conductor of electricity that it is used as an insulator, but the ability to print circuits onto flexible plastic opens up options in the design of flexible screens and electronic paper.

The research has been published in the journal ChemPhysChem by team members from the University of New South Wales and the University of Queensland.