My oleate-capped NaCeF4:Gd,Tb NPs have been synthesized via the thermal decomposition method. 1mmol of NPs has been dispersed in 20 ml of cyclohexane.
I have tried dissolving 1 ml of NP in cyclohexane in 10 ml of 33 mg CTAB dissolved in DI water. I have washed my NPs with acetone 6 times, but I am unable to obtain a transparent and clear phase transferred solution. It is still a little cloudy after 24 hours at room temperature at 750 rmp with the first 3 hrs at 70 degrees at 1400 rpm.
However, I have carried on with the reaction and add in 150 microlitre of TEOS dropwise after adding in another 20 ml of DI water, 150 microlitre of 2M NaOH, and 3 ml of ethanol at 70 degrees 1000 rpm. The CTAB was removed via a ligand exchange method with 0.3g of NH4NO3 in ethanol on the next day.
May I seek advise on what went wrong and how I can improve?
The pictures contain before and after coating of the mesoporous shell.
Either use IGEPAL or Brij surfactant instead of CTAB. It may form cloudy in cyclohexane.
4mL IGEPAL +40 mL cyclohexane ---> Mix and sonicate 10 min
Add required amount of NPs suspension in cyclohexane to the above emulsion.
Add TEOS and Ammonium hydroxide
sonicate and centrifuge to collect the samples
dissolve in hydrophilic solvent.
Sonication and temperature is major factor affecting your silica coating
Try this one.
Prof. Alaa A. A Aljabali
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