Cupric Sulfate and Ascorbic Acid

I picked up some cupric sulfate [secure.sciencecompany.com] and ascorbic acid [www.amazon.com] recently. Cupric sulfate is either a blue crystal (pentahydrate) or a white powder (anhydrous). You can change one to the other by adding/removing water.

I tried an experiment where I mixed anhydrous cupric sulfate, ascorbic acid and a bit of water. What I got was a brownish mush that was almost entirely nonconductive. I'm guessing I got cuprous oxide out of the mix. Maybe using something other than water as the solvent would help. Both appear to be soluble in glycerol and methanol. I'll have to see if I've got any lying around.

...or it could be that "you can't get there from here" and there's just no way to extract copper from cupric sulfate using ascorbic acid.

Well the only ways i know of to reduce Copper 2+ to elementary copper is eitjer by electrolysis or by deposition on a less noble metal, as zinc, iron etc. deposition usually results in an uneven porous surface that won't conduct well. As for ascorbic acid, or any reducing agent, you will most likely only be able to reduce Copper sulfate only to its Copper 1+ form, just a different salt, really.

nevertheless, the color you describe could be of some metallic Copper precipitating. but the same porous structure is to be expected and that may be the reason of the high resitance

Edited 1 time(s). Last edit at 03/07/2008 03:10PM by Fernando.

... some days ago we had to cover a thin gold-surface of some hundred nanometers with 10 microns copper, what was made electrolytical with two electrodes - one connected to the gold-surface, the other free in the blue (cupric sulfate?) fluid ...

I know too, that you can cover a surface with a conductive paint and then 'draw' pure gold-lines with a pen with a felttip, filled with the gold-electrolyte and powered by a single baby-cell.

Normal galvanic isn't very fast, but for electronic devices you usually don't need thick trays, maybe this micron-thick galvanic painting is enough for PCB-drawing?

Viktor

What's the brand of this conductive paint you are talking about? Is it available in shops or online? if we can get a conductive path painted with this and improve conductivity by electrolytic deposition of copper this would be the easiest solution.

I have made some conductive resins loaded with copper powder filler, but the resistance was in the order of 1 Ohm, which is to much for circuit boards.

Edited 1 time(s). Last edit at 03/07/2008 04:26PM by Fernando.

Hi Fernando,

on monday i'll check some infos and sources.

Normally you can use a common silver-conducting-paint (german 'Silber-Leitlack') or graphite-spray (german 'Graphit-Eisen-Spray').

With the galvanic felt-tip you can simply 'paint' pure gold on conducting surfaces or the conducting paint - here i'll post some links, but you can find some infos in wikipedia too ...

Viktor

You know, you can cupric sulfate onto a metal and get a copper plating? [steampunkworkshop.com]

If your looking for copper sulfate, try a garden store, it is commonly used as an algaecide for small ponds.

Maybe instead of putting down expensive conductive ink why not put down copper powder and plate it together?

... here: - [www.selva.de] - i found some infos for galvanic art-work.

And here the shop: [www.selva.de]

In the past i ordered some components and experimented with micro-galvanic fixing of platinum micro-wires on gold-pads - worked fine, but i needed only thickness of some microns of the gold-coating/fixing.

Cuprum-galvanic should be much easier ...

Viktor

Edited 1 time(s). Last edit at 03/11/2008 04:43AM by Viktor.

Quote
spota
Well the only ways i know of to reduce Copper 2+ to elementary copper is eitjer by electrolysis or by deposition on a less noble metal, as zinc, iron etc. deposition usually results in an uneven porous surface that won't conduct well. As for ascorbic acid, or any reducing agent, you will most likely only be able to reduce Copper sulfate only to its Copper 1+ form, just a different salt, really.

nevertheless, the color you describe could be of some metallic Copper precipitating. but the same porous structure is to be expected and that may be the reason of the high resitance

There are two threads on the ScienceMadness forum that discuss precipitation of copper with Ascorbic acid and other techniques. While this is not mainstream science it has been repeatably demonstrated and even generated an academic paper not too long ago.

decomposition ascorbic acid
[www.sciencemadness.org]

Precipitated copper powder
[www.sciencemadness.org]

A chemical reduction approach to the synthesis of copper nanoparticles
[link.springer.com]

Regards
Kalle

Edited 1 time(s). Last edit at 07/12/2018 03:05PM by KalleP.

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Kalle
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Lahti, Finland
The only stable form of government is Open Source Government. - Kalle Pihlajasaari 2013