electroplating conductive polymer

Hi all!

After my vacations i have been a little slow to set up some new test procedures and i have decided to start with something quick and easy. On Saturday, July 07 i had prepared a copper powder loaded adhesive which i spread in rough threads over a plastic board (watch it here [builders.reprap.org]). These threads had shown to have a quite high resistance of 70 kOhms sometimes lower, but always in the range of the kOhms. I had discussed that the next step would be trying to plate it by using a copper salt solution.
That's what i did today. nothing fancy: a copper salt sold in gardening shops as fungicide. it wasn't even copper sulfate which would be the ideal salt to use. I connected the - pole to the threads on the board i had fabricated and plunged a large section of copper cable in the solution, connected to the + pole. The reaction went on fairly slow but i got it going, wich was more than i had expected. After just a couple of hours i removed the board from the solution and measured the resistance again: 6 Ohms!!!

It's still high but it's a 10000 fold decrease! I know that i can do better than this by increasing the initial copper power load in the adhesive, by using a proper copper sulfate solution for electroplating and by leaving it the whole night. Also I want to try and print some of these threads on some proper PCB material and make the plating thick enough to have a try and weld something in it. I guess we are getting very close at having a solution for printing boards

that is definitely good news! keep up the good work Fernando.

Thanks!

When i have a try at this with the right conditions I'll post a complete resume in the builders blog. After that we may want to start thinking on how to standardize this process for everybody to be able to reproduce it.

Cheers!

Great going, Fernando!

Excellent work!

One of your major issues is likley purity. A garden fungicide likley has stablizers and other components. These are plating out along with everything else. Have you attempted to add a small amount of sulfuric to the bath, that usally increases plating thickness. And of course a larger power supply would also speed the process. Assuming that you cant find a cheap source of copper sulfate its worth noting that dumping copper into sulfuric is a easy way to make high purity copper sulfate. Thats the way that commercial copper platers regenerate their baths.

Here is a small scale commercial system (1.5gal) that might be worth ordering since it comes with all of the equipment (other than power supply) and a lot of free support. Although in our case the degreaser seems overkill.

They seem very focused on the DIY systems and do talk about electroforming over conductive waxes and paints. It is however $170 and I have no idea if they ship to the EU. It might be possible to simply buy a small amount of the raw chemicals and then request MSDS for each of them to come up with an appoximation. Everything is listed as non-hazardous (at least in the US) so maybe shipment to the EU would be possible. If not access to their online manual is only $15 per year and would likley catch a lot of mistakes quickly.

[www.caswellplating.com]

Even without that we should be able to approximate everything, except for maybe the brighteners. I dont know the chemistry of the brightners, they tend to be very different from material to material.


Mike

The thoughts and ideas expressed in this post do not reflect those of my employer and are intended only as communications between individuals. Any attempts at implement are at your own risk

Edited 1 time(s). Last edit at 09/12/2007 09:11PM by ohiomike.

You may find that there is a lot of information on the web detailing how to perform electroless plating on polymers so that they can be used in scanning electron microscope's (SEM). A very quick google came up with this for example. Unfortunately you will find most of the papers like this will be behind pay wall's.

If you do find a paper that appears to contain just the information you need then PM me and I might be able to help.