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Making Photopolymers Conductive

The photopolymer we are presently using is a water-etch or water soluble product and in the process of silvering it, to make it conductive, the image is destroyed because of the water based nature of the silvering. Unfortunately applying a lacquer or other coating would distort the extremely delicate engravings which were etched into the photopolymer.

I would like to know if any of your readers could suggest a process to make the photopolymer conductive, so that it may be used as a matrix in a nickel sulfamate electroforming process without distorting the images.

Alan Sadowski
- Oxford Mills, Ontario, Canada
1996

Alan:
Most aqueous an semi-aqueous developable photo resists stand up well in acidic solutions but not in alkaline solutions. I'm not sure how you are silvering but you might see what the solution pH is.

A few other possibilities might be to use electroless nickel in place of the silver, process solutions are acidic. The other thing might be to re-expose the photo resist after you have gone through the development to make sure you get maximum crosslinking of the polymer, that might improve ability to withstand the silver solution.

Paul Stransky
- Putnam, Connecticut
1996

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If your photopolymer is one of the acid-stable varieties such as dynachem UH10, you can render it conductive through all acidic steps using a tin chloride followed by Palladium Chloride sensitizer process such as Macuplex offered by Macdermid. This can be followed by Electroless Nickel or other Electroless deposition steps. They work great on those thin dryfilms.

Regards,
Dave

Dave Kinghorn
Chemical Engineer
SUNNYvale, California
1997

Why don't you try the very old printers method of rubbing graphite onto the photo etch using a soft brush. graphite is conductive but takes longer to cover the article than does silver,try to use as low a temperature as possible until the article is completely covered in nickel. I would be surprised if this does not work. please note that the article must end up black and shiny to be completely conductive.

Ken Foyn
- Durban, South Africa
2000