This Question was answered by Dr. Abdelkader BOUAZIZ. Thank you very much.
Missing information:
The surface is -OH functionalized. pH of the water sol is about 2~3.
Dear Byoung-Gi Park, the following paper shows the effect of ethanol on mesoporous silica properties. My Regards
doi:10.1109/icbme.2018.8703594
Another interesting document.
https://doi.org/10.1016/j.cej.2020.125427
Dr. Bouaziz, thank you very much for your kind answer. I have read the two articles what you recommended. These are for producing silica nano particles utilizing Stober method. However, my question is not for producing silica nono particles.
Let me give you details. My question is why the color of solution becoming milky white once water solvent substituted by ethanol.
The process are like this:
1. Step 1: Producing noano particles by Stober method (transparent for both water and ethanol dispersion).
2. Step 2: Thermal treatment for -OH activation on the particle surface.
3. Step 3: Wash and leansing the dispersion solution by water (Transparent).
4. Step 4: Substituted the water as dispersion solvent to ethanol (Becoming milky white during the course of the sovent substitution).
5. Step 5: Producing 7wt% nano silica particles dipersed in ethanol (Milky white).
Why the solution in Step 5 becoming milky white? My question is not about Step 1.
I have charaterized by LRS and TEM. This penomenon is not by agglomeration. Look like Mie scattering penomenon coming up.
Yes, the same that happens while synthesizing SiO2, took place in dispersion of it. In ethanol coarse and regular shape particles are formed, this is why you saïd mesoporous spherical.
Dr. Bouaziz, then how can I remove the white color in Ethanol dispersion?
It is not a color, it is just the light diffraction of SiO2 nanoparticles.
I see. At the first place, asumed that it is by Mie scattering due to Solvation thickness. 70nm + solvation thickness×2. Maybe I am misunderstood.
Dr. Bouaziz:
Thank you your keep following. Let me ask you one more question.
Why the light diffraction in ethanol, can not be observed in water dispersion? In what circumstance the diffraction occur?
Have nice weekend.
May be yes, but generally plasmonic scattering is adressed.
https://www.nature.com/articles/lsa201460
https://tinyurl.com/43evekac
https://doi.org/10.1021/acsphotonics.0c01554
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