Composite plastics have high conductivity and strength

The material, which can be made into fibres or sheets, could find a use in strain monitoring and has already been tested to this end in the sails of high-end yachts competing in the Americas Cup.

Conductive polymers have existed for some time, but are generally made from exotic semi-conducting organics, and restricted to organic solar cells, printing electronic circuits, and organic light-emitting diodes.

A team at NanoForce, a spin-off from Queen Mary University of London, set about creating robust plastics that could conduct at near-metallic levels.

‘You can just use normal polypropylene or polyamide, so they’re much more stable than these fancy semi-conducting polymers,’ Ton Peijs, technical director, told The Engineer.

The team uses additive multi-walled carbon nanotubes at a weight percentage of around one per cent. In isolation, the nanotubes show excellent metallic conduction, but the challenge has been to incorporate them into composites.

‘If I want to make a conductive polymer composite I need to mix in these nanoparticles and you don’t want them to be all agglomerated here and all agglomerated there because then they are too far apart and never form a network — but if they are all perfectly and evenly dispersed, then they are also quite far apart,’ Peijs said.