I have synthesized AgNPs solution by adding 0.0274g of AgNO3, 0.0135g of Glucose, 0.05g of PVP and 0.00011g of Sodium carbonate to 50ml of distilled water under stirring and after 10 minutes the mixture was heated to boil under vigorous stirring condition the color of the solution gradually become light blackish and then 15 µL of triethylamine dropped into the mixture and the color of the solution become brown which confirms the formation of AgNPs.
Now from this synthesized solution, I want to make 30wt% AgNPs colloidal solution in ethanol. To do so what I need to do? Please suggest me.
Brown suggests the formation of silver oxide Ag2O and not silver. I do not believe that you can load to 30 wt% and get a stable colloidal suspension. See also:
September 2nd, 2015 Silver colloids and invisible ink
https://www.brainshark.com/malvern/vu?pi=560497681&b=1&tx=120486&c1=22
Let's calculate. 0.0274 g of AgNO3 contains 0.0174 g of Ag. After separating all by-products (for example, drying sol, dissolving of PVP+silver in alcohol, and drying again) the "ideal" residue will contain 0.0174 / (0.0174 + 0.05) * 100 = 26% silver. You cannot make a 30% AgNP solution from it, don't try.
Dear Shcherbakov,
Thak you for your answer. I have a doubt, in the final calculation, you have added a value 0.05 in the denominator, from where this value came? Is it due to the addition of ethanol?
Because you use 0.05 g of polyvinylpyrrolidone as a stabilizer. It forms strong bonds with silver surface and it is unlikely to be removed from the system by physical methods. The dried product PVP-AgNP dissolves well in alcohol (unlike, for example, precursors and other inorganic salts) - it is possible way to purify this nanocomposite, but it is unlikely to be separated. Therefore, 0.05 is added to the sum in the denominator.
Thank you again for your elaborate answer. I have one more query, suppose I have centrifuged the solution and collected PVP-capped AgNPs, Now if I dissolve these AgNPs in 53.4 micro liter of Alcohol will it be 30 wt% w.r.t. alcohol?
You may able to get to 30% Ag loading but they won't be nanoparticles......
Nabadweep Chamuah,
I think, you can separate excess of PVP by centrifugation, because strongly bonded polymer' content will be less than initial and more part of it will stay in solution. Really, if your supernatant is colorless, and sediment will be dissolved in alcohol, the silver’s content will be some less than 30%. Let’s re-calculate. Silver content will be 0.0274/170*108 = 0.0174 g. Weight of solvent (alcohol) ~53.4*0.8/1000 = 0.0427 g. Weight of solution is 0.0427 + 0.0174 = 0.0601. So, silver will be 28.95 wt. %. However, some residual PVP will increase the total weight of solution and decrease silver’s percentage – we don’t know exactly this quantity. Try to weigh the resulting solution.
Alan F Rawle,
PVP strongly stabilizes AgNPs, keeping their habitus. I repeatedly made even a dry PVP-AgNPs powder containing more than 50% of silver, which can be easily redispersed in water or alcohol forming good sol of initial nanoparticles.
Best regards
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