Copper particles electrify paper

Nano-sized copper particles, developed by a polymer chemistry research team at the University of Helsinki, also change paper to a material "sizzling" with electricity.

 Chemistry laboratory

In the future, instead of printing ink, paper surfaces may contain electric intelligence. In a polymer chemistry laboratory study, it was found that copper particles shielded with the polymer compound PEI can be used for giving paper, for example, a highly conductive surface.

Many different nanoparticles have been made from gold and silver, but the polymer researchers of the University of Helsinki are interested in copper.

"Paper requires an alternative which is more inexpensive than precious metals. It seems that no one else has earlier come up with the idea of combining copper with this particular polymer," says Professor Heikki Tenhu, leader of the research team.

Polymers are macromolecular compounds whose characteristics change according to temperature conditions. However, the low melting point (less than 200 degrees Celsius) of a new copper particle took the researchers completely by surprise. "This kind of particle can be utilised without the paper being burned," Tenhu explains.

The studied polymer also prevents copper oxidation. "In the course of time, copper roofs turn green. A nano-sized copper particle may become oxidised within a microsecond unless it is polymer-shielded.

Polymer-shielded metal particles can be used in the electronics industry, for example. An electronic circuit printed on paper would be very light and flexible.

The results of the study were recently reported in the Journal of the American Chemical Society, an international publication of the field. The polymer chemistry research team of the University of Helsinki is part of the Centre of Excellence in Functional Printable Materials.

Centre of Excellence in Functional Printable Materials

Text: Marja Lintula
Photo: Veikko Somerpuro

Translation: AAC Noodi Oy

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