mymm
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alumina coating by sol-gel
I am working on my MS' thesis,
I want to produce alumina by sol-gel, using aluminum isopropoxide as precursor. I have read some articles in this regard, but I have a problem in
making the sol.
I want to use ethanol as solvent, and work in room temp.
Can any one help me in the process of dissolving aluminum isopropoxide in ethanol in order to get a clear sol?
Thanks
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Nicodem
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22-4-2012 at 04:11 |
Pyridinium
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What happens when you try to dissolve the isopropoxide in EtOH? Are you talking about a difficulty dissolving it, or in forming a sol?
Did you ever try dissolving it in a mixture of EtOH / toluene? Not that it would necessarily solve your problem-- just curious.
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mymm
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Actually I can not gain a transparent sol just by adding AIP in ethanol! It becomes cloudy and white!
I've read s.where that Acetylacetone should be used as a chelating agent in this case; and for hydrolysis nitric acid should be used in order to
adjust PH to 4.5.
Is that right?
No, I haven't use this mixture yet, but I may try it as soon as possible! Tnx
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mymm
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sol-gel using aluminum isopropoxide as precursor
Hi,
I'm planning to make alumina coating by sol-gel.
Do any one know the exact procedure of making the sol by adding AIP in ethanol? Is any chelating agent such as Acetylacetone necessary for
dissolution?
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Nicodem
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Threads Merged
23-4-2012 at 09:29 |
Nicodem
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Quote: Originally posted by mymm  | | Actually I can not gain a transparent sol just by adding AIP in ethanol! It becomes cloudy and white! |
Just how sure you are that your ethanol is anhydrous? You better do a Karl-Fischer. Or just buy a new one.
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Pyridinium
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| Quote: Originally posted by Nicodem | | Quote: Originally posted by mymm | | Actually I can not gain a transparent sol just by adding AIP in ethanol! It becomes cloudy and white! |
Just how sure you are that your ethanol is anhydrous? You better do a Karl-Fischer. Or just buy a new one. |
That's what I was thinking. If you try mixing an aromatic such as toluene with your ethanol and see cloudiness, there's water. Then again if AIP has
cloudiness, there's probably water.
Maybe some good ol' drying agents first?
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mymm
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My ethanol has < 0.1 % water and I think it's not too bad.
ls it necessary to gain a clear and transparent sol before hydrolysis?!
last time I used acetylacetone and after 2-3 hours stirring, I saw no particle at the bottom of container. But it's color was milky, not transparent!
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daragh8008
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The transparency of a sol is not alway necessary for film formation. There are usually many other factors that need to be addressed, typically the
final properties of the film are most important. Often milky looking sols are an indication that the organometallic precursor is highly cross linked
forming suspended particles >10nm. Polymeric sol in contrast are typically clear. The final properties of your film will depend on the sol so this
will need to be investigated. Depending on the reactivity of your precursor and how it is catalysed etc will influence this. Also particularly
reactive precursors will tend to from the particles, this is why often the literature you will see sols being prepared at low temperatures to reduce
the rate of the cross-linking.
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mymm
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Thanks daragh8008.
Your post was very helpful. It seems you know sol-gel very well. Can I ask you my questions by email?
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watson.fawkes
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Don't do that. It's not like you're the only person interested in
reading the answers.
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