[Tosyl1]

Hi guys,

Does anybody have exp. synthesizing silver nanocolloids?
I am using 0,1M AgNO3 + 2x as much formaldehyde as reducing agent + NaOH for better reactivity. The solution is stabilized by polyvinylpyrrolidone (MW 40000).

Regardless which order the reagents are mixed, the solution turns turbid grey, obviously not what I am expecting. Been struggling with this over 2 weeks now. Hint anyone?

T1

[Stepan]

What would you expect to see as an indication that you do have nanocolloids?

[Tosyl1]

I expect a brown or pale yellow transparent liquid. That's what my colleague obtained. But he used micromolar AgNO3 concentrations and other reducing reagents.

After reaction I am trying to remove the PVP by washing with acetone. I would like to see Ag particles separated from solution, didn't manage to. 

Ah btw, my aim is to prepare 20% w/w Ag nanoparticle solution in diethylene glycol.

T1

[Stepan]

I am not sure if the concentrated solution is stable enough. Maybe this is the reason why your particles are larger. Maybe you can start with diluted solution and remove some solvent later via osmosis?