Sciencemadness Discussion Board - Conductive silver ink

Conductive silver ink

Random - 19-1-2013 at 07:23

http://www.youtube.com/watch?v=EBlqPS8boLI

Here is a NurdRage video which describes how to make silver ink that is conductive.

Quote:

1g of silver acetate is completely dissolved in 2.5mL of ammonium hydroxide (30%). 0.2mL of formic acid is added dropwise with stirring. Solution is then capped and allowed to stand for 12 hours. The solution is decanted and then pushed through a 0.2 micrometer pore syringe filter. Draw it onto a surface and let it dry. Then heat it to 90 celsius to sinter it into solid silver.

Now, it sounds pretty easy to make, but I suppose formic acid is used for reduction. Now I don't have formic acid even in so small amounts, so would something other work? Like ascorbic acid? Or H2SO3?

Hexavalent - 19-1-2013 at 07:27

Yes, in theory (to the ascorbic). I've used it to prepare ultrafine copper powder previously, so I'm sure something similar could be employed here. Perhaps even glucose could be used, making the reaction similar to the classic "silver mirror".

Secondly, formic acid solutions can be obtained pretty widely as "Limescale Remover", and, at least here in the UK, it is quite inexpensive.

[Edited on 19-1-2013 by Hexavalent]

blogfast25 - 19-1-2013 at 09:36

Quote: Originally posted by Hexavalent

Secondly, formic acid solutions can be obtained pretty widely as "Limescale Remover", and, at least here in the UK, it is quite inexpensive.

Very true but some are acetic acid and I've found lactic acid in some of them too. If it's not labeled, the smell should be a dead give-away!

[Edited on 19-1-2013 by blogfast25]

bfesser - 19-1-2013 at 09:51

There's a company called Chemtronics that makes <a href="http://www.chemtronics.com/products/product.asp?id=7" target="_blank">pens</a> for drawing conductive circuit traces. I searched for the MSDS and found that they have one using <a href="http://www.chemtronics.com/products/americas/MSDS/4001.pdf" target="_blank">Ag</a> and one using <a href="http://www.chemtronics.com/products/americas/MSDS/CW2000%20UK%202011%2012%2020.pdf" target="_blank">Ni</a>. With this info, it shouldn't be too hard to reproduce the ink. I have Ag powder produced by reducing AgNO<sub>3</sub> with ascorbic acid—maybe it's suitable?

The Ag pen ink MSDS practically reads like a recipe:

Quote:

Chemical Name—CAS No.—Wt. % Range
Silver—7440-22-4—35.0-65.0
Propylene Glycol Methyl Ether Acetate—108-65-6—2.0-20.0
Ethylene Glycol Monobutyl Ether Acetate—112-07-2—2.0-20.0
n-Butyl Acetate—123-86-4—5.0-35.0
Acrylic Resin—mixture—15.0-40.0

Random - 19-1-2013 at 16:10

Quote: Originally posted by bfesser

There's a company called Chemtronics that makes <a href="http://www.chemtronics.com/products/product.asp?id=7" target="_blank">pens</a> for drawing conductive circuit traces. I searched for the MSDS and found that they have one using <a href="http://www.chemtronics.com/products/americas/MSDS/4001.pdf" target="_blank">Ag</a> and one using <a href="http://www.chemtronics.com/products/americas/MSDS/CW2000%20UK%202011%2012%2020.pdf" target="_blank">Ni</a>. With this info, it shouldn't be too hard to reproduce the ink. I have Ag powder produced by reducing AgNO<sub>3</sub> with ascorbic acid—maybe it's suitable?

The Ag pen ink MSDS practically reads like a recipe:

Quote:

I have researched on this subject too, except I have found those materials hard to obtain. It's definitelly more useful though, since you can put it more easily on the paper surfaces to make simple circuit boards.

I have also found a similar, yet a little bit different recipe, which works the same if I'm correct.

http://www.youtube.com/watch?v=dfNByi-rrO4

check 1:35 for alternative room temp recipe

Too bad, again, I can't obtain some of these materials. If I'll be able to synthesize them from OTC chemicals, I'll sure attempt it.

Quote: Originally posted by Hexavalent

Yes, in theory (to the ascorbic). I've used it to prepare ultrafine copper powder previously, so I'm sure something similar could be employed here. Perhaps even glucose could be used, making the reaction similar to the classic "silver mirror".

Secondly, formic acid solutions can be obtained pretty widely as "Limescale Remover", and, at least here in the UK, it is quite inexpensive.

[Edited on 19-1-2013 by Hexavalent]

Interesting, I will definitelly try making small amounts and test those reductants.. I am from eastern europe so only OTC acids are HCl, H2SO3 and phosphoric for rust removal. Haven't found any formic acid. There is actually one route:

ethylene glycol ---copper---> oxalic + glycerol ---> formic

but it seems like a mess especially since I don't have glassware for distillation

Fleaker - 21-1-2013 at 17:23

We do this with sodium formate at 65*C and pH 4 on 300 g/L silver nitrate. It is very selective for silver, ignoring copper. Nickel in high concentrations will co-reduce.

There is a wide variability in growing fine particles. The more rapidly you form it, the finer they will be. Slow addition of reagent allows for the formation of a heavier sand/sponge.

Poppy - 21-1-2013 at 17:58

I made a pretty colloid of silver suspension once, I think I had silver nitrate, formaldehyde and NaOH 1M solution and just mixed them all and voilá, a silvery putty of very fine silver, it was transparent and probably would coalesce for some reason but I was scared and threw that off lol

Random - 22-1-2013 at 06:25

Yeah you see guys, I have some formaldehyde, maybe I could use it here.