Researchers at the University of Helsinki in Finland have succeeded in producing nano-sized metallic copper particles that could enable the production of electronic devices printed directly onto paper.

The research group was synthesising and studying so-called intelligent polymers - large-molecule compounds that change their properties according to the changing ambient conditions.

They found that as the size of copper particles was reduced to a nano-scale (in this case, about 8nm), their material properties underwent substantial changes.

Paper electronics as cheap as chips

This reduced the particles' melting point to the level where they could be attached (or 'sintered') onto paper with the help of protective polymers.

When they measured the resulting conductivity, the scientists found that it was possible to form electricity-conducting layers and patterns on paper at relatively low tempatures (15-200 degrees C).

The ability to create intelligent patterns on paper with miniscule amounts of nanotech copper could lead to a new era of low cost, even disposable electronics.

Newspapers could include video footage on the front page, documents could include a digital version in tiny Flash memory chips and bank notes might incorporate sophisticated anti-forgery watermarks.