Good contact for a smooth relationship between nanotubes

23 June 2008

Plastics have undergone enormous development, from a protective isolator of electrostatic charge to a conductor of, for instance, electricity. The Dutch Polymer Institute started a project in May 2005 to develop an electrostatic conductor using as few carbon nanotubes as possible. "Making plastics conductive while retaining the mechanical properties at the lowest possible cost - that means adding the fewest carbon nanotubes as possible to the plastic," says project leader Dr Paul van der Schoot of the TU/e. The practical consequence is transparent conductive plastic.

The project findings will be appearing in this month's leading journal Proceedings of the National Academy of Sciences of the USA (PNAS). In the new compound the carbon charge of the carbon nanotubes is so low that even the black colour is no longer present. This transparency also makes the conductive plastic suitable as an anti-static coating or for the reverse of a computer or TV screen. DPI project leader Dr Paul van der Schoot, Theoretical and Polymer Physicist at the Eindhoven University of Technology (TU/e) gives a simple explanation: "We have shown that in blending carbon nanotubes with plastic, the property of the material determines how the contacts between the nanotubes develop and whether there is a smooth relationship. We are to regulate this using a particular supplement or choice of plastic. If the plastic and the nanotubes take to each other and interact well, then the contact becomes intensive and there is better electrical conductivity. This is provisional on the nanotubes not becoming too enthusiastic about each other, otherwise there will be no reaction with the plastic polymers and no relationship will be possible."

Conductive, transparent and cheaper plastic

Dr. John van Haare, Programme Area Coordinator at the Dutch Polymer Institute: "The DPI project aims to minimise the percentage of expensive conductive components while still achieving sufficient conductivity. This is why we use carbon nanotubes, which are very thin and can be very long. This research has shown that a low percentage of very long nanotubes and a high percentage of shorter ones has the same result as the more expensive alternative: 100% long nanotubes. It is therefore not essential that the tubes lie right next to each other."

The DPI project will run through until the end of April 2009. The theoretical part has been completed by Andriy V. Kyrylyuk, who has been working as Post-Doc on the project. DPI has patented the technology. Under the supervision of Professor Cor Koning of DPI partner the Eindhoven University of Technology the research project will be continued and verify the theory in practice.