Woven superconducting material is light and pliable “like cling film”
Image credit: Oliver Dietze
German physicists have developed a new nanomaterial with superconducting properties. Unlike conventional superconductors, this material is light and flexible, making it ideal as a protective coating for space tech and medical devices.
The novel material, despite its underwhelming appearance – like “a charred black piece of paper” – has astonishing qualities.
When cooled, superconductors have zero electrical resistance; they can conduct electricity perfectly as electrons flow unrestricted through the atomic lattice. They are characterised by the Meissner effect; the expulsion of a magnetic field.
This is a physicist’s favourite parlour trick as a variety of objects – including trains and frogs – can be made to levitate above a cooled superconductor, so long as the magnetic field is strong enough.
Most superconducting materials today are dense, rigid and brittle, limiting their practical applications. Scientists have been working to develop more versatile superconductors, using materials such as graphene.
The researchers, primarily based at Saarland University, took an unconventional approach to developing the new superconductor. They wove a mesh of tiny plastic fibres, and high temperature superconducting nanowires, using a technique called electrospinning. This is normally used in manufacturing of man-made fibres.
The physicists forced a liquid material through a spinneretto – a tiny nozzle – and applied a voltage. This produced nanowire filaments a thousand times finer than human hair. They then heated the mesh of fibres to create superconductors of the right composition.
“That [method] makes the material very pliable and adaptable like cling film,” said Uwe Hartmann, professor of nanostructure research at Saarland University.
“Theoretically the material can be made to any size. And we need fewer resources than are typically required to make superconducting ceramics, so our superconducting mesh is also cheaper to fabricate.”
The film is approximately one hundred times less dense than a conventional superconductor, with a cubic centimetre of the material weighing in at 0.05g. A coat of the nanomaterial could provide low temperature protection from electromagnetic fields without weighing down a system, or could be used in flexible cables, or to aid frictionless movement.
“This makes the material very promising for all those applications where weight is an issue, such as in space technology. There are also potential applications in medical technology,” Hartmann said.
The research was supported by the Volkswagen Foundation and the German Research Foundation, and results have been published in multiple journals. The team is looking to develop applications for their novel material along with partners in industry.