Creating copper nano particles Answered
Be it conductive ink, decorations or just a special pigment for your paint project, Copper is nice.
Only problem is grinding this soft metal fine enough to be of any good use.
A not so well documented feature of food additives is that they often have "unwanted" side effects.
In our case E300, Ascorbic Acid or just Vitamin C.
So how to make copper nano particles with it you might wonder?
Prepare a well saturated solution of Copper Sulphate, you find the blue crystals in the gardening section together with fertilisers.
It is best to use destilled water and not plain tap water, if in doubt go at least with the demineralised stuff for batteries.
Adding E300 either dissolved in water or directly as crystals will start a nice reaction.
The copper solphate is reduced back to metallic copper.
There are a few problems though...
For best results you need a saturation copper sulphate solution, low temperatures and a magnetic stirrer.
This produced the finest particles for me at around 5°C.
But even warm or at room temp the constant sirring is beneficial for even particle sizes.
The ascorbic acid is used up in the process as well.
You can start with a little and see how much you end up with in terms of a layer of copper particles at the bottom.
Adding more E300 will cause a "rain" of fine copper particles - once this no longer happens you know the copper sulphate is used up as well.
A dark greenish color of the solution will indicate this as well.
Getting the copper out of the glass...
Keep in mind the copper is extreme fine!
As long as it stays in the solution it won't oxidize or otherwise react.
Once out and in contact with just water and air oxidation happens quickly, after all it is pure copper...
I found removing the watery solution and then adding destilled water to repeat the process is a good start.
The waste from the first round can still be usefull though...
In the final round I try to remove as much water as I can and then add methyled spirit to prevent the reactions.
You can use oil as well or do a quick vacuum drying and store it in a sealed and oxygen free container.
What to do with it?
As a condictive paint with the right binder it only needs some rubbing with a smooth tool to create a conductive cover with a low resistance.
In a clear paint or resin it provides some stunning color effects.
You can even dust the dry powder onto a freshly painted surface to get a copper look.
Leave without a top coat and you quickly get an old copper or even green look.
If you ever wanted extreme fine metal particles you will come up with more ideas...
Like shielding or sintering....