How do you synthesize different shapes of Magnetic nanoparticles (Iron oxide or Nickel ferrite or Co ferrite) using a microwave? What parameters do you use to tune the shapes?
Hi Sundhanshu. Iron Oxides are microwave assorbing materials, this means that they strongly couple with elecromagnetic waves and heat up very rapidly. Therefore, something that can be tried to shape the morphology of the particles by microwaves is certainly the irradiation power/temperature and/or the solvent. Like for all materials you can play with templating agents, pH and so on as suggested by T. Mazon.
Additionally to all the past statement try on concentration differences, one mid concentrated trial lets say 0.1M and other diluted trial 0.001M, just to ensure the concentration effect in your system. Everything else should be maintained even the amount of templating agent in order to track just conc. effect. Finally I want to make notice that the mixture of solvents can have high potential in the template effect, e.g. use H2O:EtOH:iPrOH in the same flask and vary their amounts in order to achieve solubility of the system but concomitantly phase transfer agent. Once the core particle is formed it is able to phase transport to the energetically stable phase and so on.
You should paid special attention on the concentration as Hiram already suggested, good luck!
Dear all,
Thnx for your early responses. I will try my expt with respect to Inintial conc., Temp and time. But as few of you suggested for pH effect, i would like to ask " whether pH effect will change the crystal structure? i mean it may not form spinel if we decrease the pH?"
Is this shape control possible with uncoated spinels?
I never try to control shape. My the method of W/O microemulsion , because the reaction occur in water core then shape is round, however the effect of pH may take place but I have not try yet.
Dear all,
You should paid special attention on the pH effect as Sudhanshu Pati already suggested. For instance for the synthesis of spinel-type oxides such as ferrites, the pH is crucial and should be of about 10-12, otherwise intermediate phases or non-stoichiometric ferrites could be obtained.
Additionally, you could try polyol solvents with appropriate amount of water as we did in our ‘’polyol method’’
Dear TAHAR,
Can you kindly explain the polyol method here for kind reference? Kindly provide complete detail
I can confirm influence of initial concentration of metal precursor and metal:caping agent ratio. For certain set of aforementioned parameters I obtained double maximum on absorbance vs. wavelength chart. Ethylene glycol was used as reducing agent. Process was conducted in domestic microwave oven.
@Grzegorz....What salt you took for Fe? Is that FeCl2SO4? Is ethylene glycol is strong enough to increase the pH to 10+?
you can find many good references here: DOI: 10.1002/anie.201101274
Dear Mostafa, I have gone through your paper. Its a good one with no doubt but the number of core-shell examples are much less. Also i was searching for Fe3O4@ZnO or @ FeO....but could not got any method for that
dear Waseem,
I have gone through this review as well. Its a good one really
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