To observe powder particles using TEM, we must dilute the powder with solvent (by sonication, mixing, or something), before dropping them onto the TEM grid. What am I curious is which solvent is more appropriate for diluting the powder, acetone or DI water, or another solvent? How they will effect the status of the powder particles and then the observation result? Could you please share your opinion?
Best regards
Ethanol is the best option... as Dr. Klemm already said ....
you should be careful about few things....
1) the solvent should not react with the powder.... as distilled water can react in case of metal powder and form oxides..... be aware of that.....
2) It should evaporated fast....
3) the solute (powder) can disperse in the solvent.....
4) grid size (copper grid) no. of mess/area......select according to the particle size of your powder......
5) before putting it in TEM, the grid should be completely dry (follow the standard procedure)
most of the cases Ethanol used as a solvent ...as it is not react with the powder even it is metallic....
for ceramic powder / polymers you can even use Deionized water.... depending upon there disperse nature in DI water......
Thank you for sharing your idea. Could you explain why do you choose these solvents?
Thanks Volker for help me to correct my words :) Fogging, not dropping, that exactly what I tried to describe.
Regards
Ethanol is the best option... as Dr. Klemm already said ....
you should be careful about few things....
1) the solvent should not react with the powder.... as distilled water can react in case of metal powder and form oxides..... be aware of that.....
2) It should evaporated fast....
3) the solute (powder) can disperse in the solvent.....
4) grid size (copper grid) no. of mess/area......select according to the particle size of your powder......
5) before putting it in TEM, the grid should be completely dry (follow the standard procedure)
most of the cases Ethanol used as a solvent ...as it is not react with the powder even it is metallic....
for ceramic powder / polymers you can even use Deionized water.... depending upon there disperse nature in DI water......
I also used ethanol (dried faster and did not react with the samples). Thanks for all these comments and for the detailed description by Mr. Soumitro Mahanty. However, I do not agree with Mr. Mahanty in point 4, as some copper grids (as far as I know) are covered by a thin membrane (formvar, carbon?), which also has tiny holes, but these holes are (in general) much smaller than the ones in the mesh. So, the particle size can be smaller than the grid size, as the membrane acts as a substrate.
Regards
Choice of a liquid depends very much on your powder. For organic nanopowders water is often the best choice. For inorganic powder ethanol could be better; additionally for ethanol specimen preparation time is shorter (faster drying). Material of thin film on a grid is also important in choosing liquid: you want good wettability and no chemical reactions.
@Cristina .... yes there is a carbon film made over the grid ...... i have not mention that the particle size be greater than the grid size.....
particle size will be always smaller than the grid size .... otherwise how you will see the complete microstructure of your particle.......
Regards
Thank you very much for all answers! I understand that in many cases ethanol is better than DI water. But between acetone and ethanol, which one is better? Acetone is also a very popular solvent, and its boiling point even lower that that of ethanol, which means it will evaporate faster. In addition, because acetone is less viscous than ethanol, the effect of dilution may be higher.
which solvent is used in sample preparation of TEM is depend upon the type of sample either it is hydrophobic or hydrophilic. If sample is hydrophilic then use DI water and sample should be fully dispersed in water and if sample is hydrophobic then use ethanol or acetone. it is also important that drop of sample puts on which side of copper grid. hydrophobic sample should be put on bright side of grid and on other side should be hydrophilic sample.
I would say .. u can opt for the acetone for the preparation of your particles on the TEM grid .. .. plz go through this .. might help ..
http://temsamprep.in2p3.fr/fiche/fiche.php?lang=eng&fiche=30
Dear Son Thanh Nguyen, I would like to invite you to use the full text "Search Questions" function in RG. (cf. Top menu line, at right side in the rectangle field find 'Search', leftclick into the down-pointing arrow: pull down menu: Researchers, Publications, Jobs, "Questions" , klick there and insert / search for e.g.:
| dispersion powder TEM | which creates: https://www.researchgate.net/search.Search.html?type=question&query=dispersion+powder+TEM and after some second you'll get a lot of previous and recent Q&A on the matter... and yes.... it depends.... Best wishes and good luck!
Choosing the suitable solvent is indeed a critical issue in order to obtain agglomerate-free powder, which depends on your material. I suggest you to do the following; take a little amount of your sample and disperse it in DI, 70% diluted ethanol and 80 % diluted methanol if it doesn't cause you money upon examination. Then send the three samples for bath-ultrasonication of about 10-20 min. Subsequently, In each case, you need to take a single drop from middle level of the 3 dispersant and carefully put it on the grid. Then you can choose the solvent that best worked for your powder, and then you do for the rest of your samples. It is worth mentioning that you need to view the grid carefully since it got approximately 400 meshes on which a trace of your sample might be sticking on.
my powder is Ni/Al2O3 .
Which solvent is the best for diluting my powder in preparation of TEM sample?
My powder is Aluminium alloy 7XXX series
Which solvent is best suitable for TEM analysis ?
Ethanol is appropriate to use but you have to check that it is dispersing in it by sonication and not reacting.
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