Electrically conductive polymers can be found in sensors, flat displays and also special solar cells. These plastics owe their conductivity either to doping with foreign atoms or to an ordered, crystal-like structure. Researchers led by John S. Anderson at the University of Chicago have now found a completely new variant of conductive plastics. The chemists synthesized a material that had a disordered structure on the one hand, but high electrical conductivity on the other.
The basis for the new plastics formed so-called organosulfur compounds – the tetrathiafulvalenes. Supplemented with small amounts of nickel, Anderson and colleagues obtained a fine powder with an amorphous, i.e. largely disordered, structure. The researchers pressed small pellets from this powder and examined their electrical properties. To their surprise, the material showed a high electrical conductivity of up to 1200 Siemens per centimeter. Although this is significantly less than all pure metals, it is still sufficient for current transport through electrical contacts.
New plastic: Specific applications are yet to come
The researchers have not yet been able to definitively clarify the cause of this unusual conductivity. But they suspect that their organic polymer contains numerous thin layers along which electrons can move. Even if these layers change their orientation, the conductivity would be maintained because of an irregular overlapping of the layers. Another advantage was the great stability of the material to air, moisture and even acids and bases.
The chemists have not yet proposed specific applications for this disordered, conductive plastic. However, they believe it is possible to produce a conductive plasticine based on their findings. Thanks to the stability and easy deformability, electrical contacts could then be constructed more elegantly than with conventional metallic conductors.