Hi, If nanoprecipitation method is used for the preparation of nanoparticles then on injecting organic phase into aqueous phase precipitates will be formed. My question is how to get discrete nanoparticles form these precipitates?
Hi, I think you get discrete nanoparticles in the solution. Do you want to separate one of them? You can deposit the solution on a glass slide using spincoater and let it dry. Then, if you look at it under microscope, you will be bale to see them separated.
You can prevent clumping of nanoparticles in a suspension by coating the nanoparticles with a suitable organic surfactant that provides a steric hindrance to co-algulation. If the nano-particles are not yet formed, you want to precipitate them at elevated temperature for very short time (and probably have to adjust the pH) before you suck up a small volume with a micro-syringe to put onto a support for SEM or TEM.
I do not have a general answer.
But, if you follow a sol-gel synthetic method you should use high dilution of reactants, seek for a slow reaction path to avoid the formation of bigger particles and/or agglomeration & Ostwald rippenning . Look for good stirring conditions and optimal pH and temperature for the particles you look at.
Separate the solid from the liquid by centrifugation. Discard the supernatant liquid (I am presuming your compound is an inorganic one, density >1). Wash with pure water a couple of times, centrifugate each time and discard supernatant.
Keep the solid nanocompound obtained. You can try to dry it by heating or vacuum.
Then you can put it as usual on a grid for SEM or TEM.
At least, in some cases it works
Hadi Maghsoudiganjeh, These are in the form of precipitates not the particles. I can see visible precipitates in the form of clumps in the solution.
Thomas Walther, Hi, I am already using Tween 80 as a surfactant. I am getting precipitates but not fine nanoparticles in the solution.
Jorge Manuel Ramos Nunes, I am using ethanol as organic phase, eudragit S 100 as polymer material and water as aqueous phase. Kindly tell if there is anything wrong in it.
Federico Svarc,you said discard the supernatant liquid but what I think that supernatant liquid contains the fine particles so we should save it rather than wasting it. What do you say?
its very simple and that by surfactant of SDS with concentration 1% W of the solution
with vigorous stirring
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