I added ammonium hydroxide and HCl to commercial WO3 NP in order to reprecipitating WO3 NP (chemical deagglomeration) but unsuccessful.
The process results in large particles settles at the bottom and suspensions slowly settling to the bottom. I cannot get NP to make water based paste.
do NP suspension look like cooking oil if its yellow colour?
Grinding the powder during paste preparation gives rough paste and crumpy looking films.
Can i add dispersant such as Acac after reprecipitation to aid in creating soft agglomerates and then sonicate it.
After this process, i centrifuge it so i can suspend it in water to prepare water based paste.
Is it neccessary to waste some of the powder as some precipitated to the bottom ?
Is there any difference sonicating it in 37 kHz or 80 kHz?
I just want a smooth film to move on PEC measurement. Got a commercial NP and ended up with big particles, how is that even possible?
Is a water based paste thick like a tooth paste?
May be you used concentrated reagents, strong acids and bases can change the properties of NPs. I think high frequency sonication is a better option. It seems like your NPs are permanently aggregated, make sure you'e followed SOP. Good handling is important. For giving a try to new method always use small amounts, you can now check the through SEM/TEM to verify their size.
Hi Muhammad Abbas
Do you have any SOP documents on handling NP ? I am new to NP.
You need to add some more clear information. You say you want to precipitate the particles but you call the process "chemical deagglomeration". Apparently, however, you are agglomerating the particles, which causes them to precipitate in large aggregates. What is the size and state (suspended particles or precipitate) of your original system and what state do you wish to achieve?
Themis Matsoukas Sorry for the misunderstanding my question caused.
I am trying to break the agglomeration of the commercial NP into NP via several methods, but not sure its correct or not. After grinding the powder with Acac and tritonX-100 , it has both suspension and precipitation. We use 50 mg of powder suspended in 100ul of water which is too little to be transferred into a vial.
Recipe: 50 mg WO3 NP, 16 ul water, 2ul of Acac , further add 100ul water dropwise and triton x-100.
Preparation of powder
Agents used in paste preparation
I tried to find information about these questions online
The picture below shows two bottles containing WO3 powder. On your left is a paste made from the nanopowder and the right contains WO3 powder suspended in water as a trial to disperse it.
The mortar and pestle is a new batch in grinding the powder but failed.
Dry powders are are generally heavily aggregated. Even if the primary particles are in the nanometer range, they are clustered in larger aggregates that are hard to disperse. Sonication may help but will not reduce the size much below a micron. I don't have experience with grinding but I would think it is also hard to decrease the size of the particles. The problem is that particle fuse together with bonds that are too strong to be broken by physical means.
I am not familiar with acetylacetone, it is not a surfactant, it possibly acts as a stabilizer/dispersant.
Dear Soong,
It depends upon the type of material which you are using, always read the Handling on label (or provided on vendor's site or mentioned in related literature, I'm mostly dealing with Gold and other metal nanoparticles so i now their sensitivity towards acids/bases/temperature/metal ions /light or any other related phenomena, so I'm always careful with my material).
As I mentioned you can only break the agglomeration if it is physical and weaker, its impossible to re-disperse with their original size if they are chemically agglomerated. Always use very dilute acids/bases if needed to use ( I use less than 1mM concentration, and few drops , if need for pH or re-dispersion ).
For making thin film you can make very dilute solution and use spin coating, I don't think grinding will help you, first find a reported literature and use small amount to reproduce their results).
acetyl acetone is just a complexing agent, mostly present in metal source, which is being used in NPs synthesis. 1-nonanol would be your solvent (dispersent ). Form your method I'm still confused, seems like you are trying to synthesize NPs from already existing NPs. Please go for related literature and start carefully.
Good luck
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