Sciencemadness Discussion Board

inkjet printable Nanoink

green - 31-3-2009 at 05:32


I have just start working on metallic nano-ink synthesis for use in direct write. So forming silver nanoparticles is not a big deal really. But separating these tiny nanoparticles from bushy stabilizer (surfactants) is a great challenge. Another concern is if I use less amount of surfactant, the silver nanoparticles tend to agglomerate. I don't want that. In order to have workable nano-ink I need at least 70% silver loaded ink. I really love to hear suggestion on this from experts, students and general public.

Green, Sioux Falls

bquirky - 31-3-2009 at 06:08

That sounds relly interesting. are you planing on printing conductive patterns ?

How are you making the silver nano particle's ? are you running an electrical discharge underwater like some of the nano carbon processes ?

is it possible to somehow chemically breakdown the surfactant and then evaporate the resulting products off ?

or using a surfactant that can be thermally decomposed into something that can evaporate ?

I cant think of a specific example Just throwing ideas around.

PHILOU Zrealone - 31-3-2009 at 06:44

Quote: Originally posted by green  

I have just start working on metallic nano-ink synthesis for use in direct write. So forming silver nanoparticles is not a big deal really. But separating these tiny nanoparticles from bushy stabilizer (surfactants) is a great challenge. Another concern is if I use less amount of surfactant, the silver nanoparticles tend to agglomerate. I don't want that. In order to have workable nano-ink I need at least 70% silver loaded ink. I really love to hear suggestion on this from experts, students and general public.

Green, Sioux Falls


Wow...70% silver this will be pasty non-liquid ink unless you manage to make super colloidal silver into a very fluid solvent...cyclohexane or ethanol
Maybe electric explosion of Ag wire in inert gas will make nano Ag particles, but I don't know if at nano size Ag is stil inert towards O2...They do it that way for ultrafine Al powder, but they must run slowly and in the cold air into the inert gas in a way to get as much metalic Al as possible and as a little metal oxyde layer...but Al and Ag are two world far appart from each other.


[Edited on 31-3-2009 by PHILOU Zrealone]

green - 31-3-2009 at 08:10


thank you all for quick reply. We are not done let ideas pour in.

Silver nanopartilces(SNP) do not oxides easily when contacted with oxygen. No wary about that at least for now. Silver salts can be reduced with proper reducing agents. But in order to be conductive ink when deposited or printed, silver particles must make enough contacts with each other. I am assuming here 70% loading will do it. Removing surfactants with temperature more 150C is to high for my process. For one thing SNP will agglomerate and does not come out of nanosize printhead.

not_important - 31-3-2009 at 08:24

http://www.conductiveinkjet.com/

http://www.piworld.com/article/sunjet-develops-platform-ink-...


although the 1st appears to put down a catalytic ink that is used with conventional electroless metal plating.

And then there is this PDF



Attachment: 2005-2 Highly Conductive Ink Jet Printed Films of Nanosilver Particles for Printable Electronics.pdf (432kB)
This file has been downloaded 1374 times

chief - 31-3-2009 at 17:34

Cool, conductive nano-silver ... ; but the inkjet can only print micro, right ?

With a 70%-silver-ink there will 2 problems, preventing nice printing:
==> The ejection of the ink is done by quickly superheating it, thereby it explodes out of the tiny holes ; now 70 % silver give a quite different (probably higher) heat-capacitance than the typical alcohol-water-glycerine-color- mixture has ... ;
==> also the silver-ink will be much heavier (standard-ink will have below 0.9 g/cm**3), maybe 8 or 9 times the density; that again will counteract any useful ejection of ink-droplets

So the electronics would have to be hacked, to allow for much stronger heating-impulses ... ; .... ....

Does it really have to be printed out of a inkjet ? Any industry will use the standard-printing-press ... ; any real-world-uses for printing the silver ? Besides: Nano was the buzzword a long time ago, these days without a real-world-use only maybe some old grandmother may be impressed by mentioning "nano" etc. ... ; and since the structures would be at most "micro": What can it do that lithography can't do better ?

Maybe you could print some sort of glue, and then pour silver-nano-dust over the sheet, which would stick on the glue-printed lines only ...

But maybe the inkjet-cartridge might be useful for reactions that have to be heated and cooled very rapidly, so that they are only hot for a fraction of a millisecond ...

[Edited on 1-4-2009 by chief]

PHILOU Zrealone - 1-4-2009 at 07:15

Quote: Originally posted by chief  
Cool, conductive nano-silver ... ; but the inkjet can only print micro, right ?

With a 70%-silver-ink there will 2 problems, preventing nice printing:
==> The ejection of the ink is done by quickly superheating it, thereby it explodes out of the tiny holes ; now 70 % silver give a quite different (probably higher) heat-capacitance than the typical alcohol-water-glycerine-color- mixture has ... ;
==> also the silver-ink will be much heavier (standard-ink will have below 0.9 g/cm**3), maybe 8 or 9 times the density; that again will counteract any useful ejection of ink-droplets

So the electronics would have to be hacked, to allow for much stronger heating-impulses ... ; .... ....


Maybe playing on the metalic nature of the ink with the help of magnetic impulse via micro spiraled wires...I have seen automatised non magnetisable metals sorting out of metalic garbage by that way...also there is that famous gun/canon powered by magnetic field to propel a bullet or a rocket made out of Magnesium-aluminium alloy....

About the media to avoid agglomeration of the Silver nano particles and to favourise conductivity by contact...maybe one could use graphite oil....graphite oil is viscous, graphite conduct electricity, the feable aromatic polarisability of the Poly-Aromatic-Hydrocarbon (PAH) planes might help sticking the Ag spheres to the molecular structure of the graphite moeities avoiding them to gather or reducing their "wish" to gather.


[Edited on 1-4-2009 by PHILOU Zrealone]

[Edited on 1-4-2009 by PHILOU Zrealone]