I want to isolate metal nanowires which I hope I made based on the following paper https://www.hindawi.com/journals/jnm/2008/782358/
I have used a slightly different concentration, the silver nitrate solution concentration was 0.25M
The vitamin B2 (riboflavin) was dissolved in two concentrations, the first was what was indicated in the paper and that did not dissolve but rather produced a dispersed yellow powdered solution, that is ok, initially looking orange or yellow, after adding the AgNO3 it goes red.
And to satisfy my curiosity, I mixed a small quantity of 3mg /100ml of Vit B2 and added 2ml of the 0.25 AgNO3 solution. The solution went pink/red.
I wanted to see the effect of adding further solution and it seemed to just be diluted.
My main question is, lets say I have formed silver nanowires.
How do I remove the vitamin b2 encapsulation from this to isolate the silver nanoparticles.
When I deposit this layer on a surface there is no conductivity whatsoever, e.g. the resistance is above 2MΩ.
I want to be able to make a conductive layer from these particles, all the papers I have read use it for biological use and do not specifically say how they isolate the particles from the complex.
There are a few key points.
1) Non-Toxic solvents are required to keep in line with green synthesis
2) Not too technical equipment or too - e.g I don't want to use an autoclave
I am thinking maybe centrifuge but not sure what speeds. I was thinking if it was possible doing this with the paperfuge
3) I am not a chemist so I don't really want to setup distillation or reflux.
4) The solution is already dissolved in de-ionised water.
Then how can I make sure they are silver nanoparticles and not encapsulated?
hello Charalambos,
as per your question what i understand you want to remove the encapsulation layer or capping agent from your green synthesized Ag NPs, according to my suggestion you can prefer centrifugation which will the best and easy method to remove capping agent.
and if we talk about the non -toxic agent you can you use alternative water and methanol washed for your particles you can use a more volatile solvent such as Isopropanol or ethanol for washing.
so firstly you can wash your particles by ultra pure water than by methanol than again by water. and finally, you can dilute it again by suitable solvent according to the prior volume.
you can confirm that the particles are not having capping agent layer or encapsulation by measuring Size (hydrodynamic dia. ) before and after centrifugation DLS (dynamic light scattering) through that you will be sure or you can opt the TEM analysis also.
centrifuge speed you can use 15000 rpm for 20 min,
hope this will help you.
Sir,
In recommendation to Nainsi Mam & Arup Sir, the best way to remove the encapsulation layer or capping agent from your green synthesized Ag NPs, would be ultra centrifugation with ethanol at about 20,000 RPM for 30-40 min.The optical and Size distribution measurements can be used to determine and ensure the removal of capping agent from Ag NPs.
You may be able to put them in a blast furnace at 500 degrees Celsius to burn off the organics. Silver's melting point is above 900 degrees.
Thank you all of you, I will try to eventually try the method most suitable for me. When I handle my solutions after a number of days I get small black spots on my fingers, so maybe I have too much silver nitrate in my vitamin b2 solutions, so I guess I have unreacted silver nitrate which when part of the mixture goes on my hand or a crystal particle from a dried slide. What do you think has happened?
Also Anupma call me Harry or Charalambos which ever you find easier :-) not sir :-)
Thanks everyone
I will try to update , if and when I carry out one or some of the methods
Harry (Charalambos)
another question, isn't methanol toxic to a degree?
How do I exchange the water solution for the ethanol in this?
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