Today, Printing electronics is mainly done on glass and plastic films (PET, PI...) by using printing techniques very close to those used in the graphic industry. Paper is not used, because it has a porous and rough surface and it has not a very good resistance to temperature. That's why Arjowiggins developed a specific paper, made with cellulosic fibers and a special coating. This paper, named PowerCoat, has a very smooth surface, measured with AFM below 10 nm (Ra). This smooth surface is ideal for manufacturing very accurate patterns and prevents the conductive particles to penetrate into the surface.
Another advantage of PowerCoat is its temperature resistance. All the chemicals, in the paper and its coating, which were unstable at high temperature were removed and replaced by temperature resistant chemicals. Thus, the sintering of the ink can be done with an air tunnel at 180 degC during 5 minutes and by using photonic sintering techniques like near-infrared (NIR) or Xe pulsed light.
At these high temperatures, the ink is better sintered and higher conductivity were achieved, especially with silver nano-particles inkjet inks for which the gain was very high.
Different patterning techniques were used during this study: screen printing, flexography, inkjet, laser ablation and conventional graphic ink printing.
For all these techniques, we compared the results of conductivity obtained on plastic and on PowerCoat paper using different conductive inks.
We also give some examples of demonstrators we manufactured using multi technology printing, including graphic printing.