I added some ethanol to my colloidal solution (800nm polystyrene spheres in water) then centrifuged it for 11min and with the speed of 6000rpm, but at the end some of the polystyrene spheres settled in the bottom, what is the problem? Is there another way to do it?
I read your question couple times, but didnt get the point. could you make it clear a bit?
Actually I want to create a monolayer of closepacked polystyrene spheres on the water surface (to use in Langmuir-Blodgett trough), for this purpose I have read in some articles that polystyrene spheres should be dissolve in ethanol. And when we add this colloidal solution on the water surface, the spheres remain on the water surface and during the evaporation of ethanol, spheres selfassemble and make a closepacked monolayer on the water. I can't use my colloidal solution because the spheres are dispersed in water and if I add this solution on the water surface, spheres won't be stable on the water surface and will drown to the water.
For this purpose I've read in the following link that we can centrifuge them:
https://www.researchgate.net/post/How_can_I_obtain_polystyrene_spheres_dispersed_in_ethanol