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Is conductive plastic equal to metal?

2004

Is there any information on surface resistivity (in Ohm/scm) on metallized plastics? Is it correct to assume it is the same as metals . Is the metal coating scratch resistant?

Regards,

Peter Behnam
Plastic - R&D - Vancouver, BC, Canada

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Metal coated plastics will have the same conductivity as the bulk metal, unless you are using very thin coatings (i.e., a few tens of nanometers). Some metals, such as aluminium, will have a tenacious oxide layer that can affect the conductivity. However, since most metallised plastics have quite thin metal, they are just as prone to scratch damage as the bulk metal. The only difference is that the bulk metal has more metal beneath the scratch and any surface damage will not affect the conductivity. In the case of metallised plastics, however, once the metal has gone, so has the conductivity! If you just want equivalent (or near equivalent) conductance, why not consider modern conducting polymers, such as polyaniline, PEDOT etc. These have conductances within a few orders of magnitude of many metals, but are, of course, quite expensive. You an get cheaper conducting polymers that are simply plastics filled with graphite, silver or even copper.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004