In order to improve the intimate contact of micro size silver flake in a solvent based printable polymer conductor I am looking for a method to precipitate nAg powder (from Ag salts) on an already designed micro flaky shape silver material.
Any suggestion?
Michele Miliciani
One important matter that you may not have considered is that in water or air the (surface of the) Ag won't be in a metallic form - rather it will be in the +1 oxidation state i.e. Ag2O... There are various routes to nano-silver (oxide) with the usual precursor being AgNO3 (and in aqueous systems the diammine salt (Ag(NH3)2+] is often utilized at pH 10 - 11. In your (solvent-based) system then you need to find a silver salt soluble in your organic liquid (may be that silver nitrate can be used). Then you could reduce to (nano) silver metal with the appropriate reducing agent - my preference would be hydrogen, H2... See this webinar (registration required):
Silver colloids and invisible ink
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W150902SilverColloidInvisibleInk.html
thank you Alan, in my process reduction with H2 is forbidden I will look to a solvent where PVP and silver nitrate are soluble...
Michele Miliciani
One reducing agent I’d avoid is borohydride - everything is contaminated with B in the system afterwards. I’ve used dilute solutions of hydrazine hydrate to produce silver (oxide) nano particles in the long past. Not sure of the applicability to your organic solvent.
you're right, also NaBH4 is too reactive to get nano size silver particles
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