I have prepared PLA based polymer nano-composite blown films of thickness ~80 microns. I want to study the dispersion of nano-particles in the films using transmission electron microscopy (TEM). But ultra fine cutting of such thin films is not possible.
Is there any other way to do TEM of thin polymer films? Any suggestion in this regard would be a great help to me.
thanks.
Embed your film in a TEM embedding resin and then you can cut it with ultramicrotome.
Embed your film in a TEM embedding resin and then you can cut it with ultramicrotome.
it depends on your task, first of all it is not clear whether you want to see particle distribution along cross section or in planar, in the case of cross section, than you need to fallow what Dr Dusevich recommended, otherwise, the aforementioned approach is not applicable. the problem in this case is that the ultramictorome can produce film with 80nm in thickness at best, but that is the same as you have, so ultramirotome will not help, but in this case you can simply put the film on TEM grid, I recommend you to use non-carbon coated grid.
Many thanks Prof Dusevich and Prof Kirakosyan for your enlightening answers.
I need to see the dispersion in planar direction but the operator of TEM suggested me that ultramicrotomy of such thin films (~80 microns) is not possible and I need to deposit the film (less than 100 nm thickness) on a copper grid using spin coating.
Prof Kirakosyan, I understand the same you suggested. but sir, I have prepared films by blown film extrusion and for spin coating I need to dissolve them in a solvent and I am afraid that it may alter the dispersion of the nano-particles.
Looking forward to hearing from you.
As I understand, you have a film type nanocomposite with thickness of 80nm that you need to transfer on TEM grid, right? post some typical SEM pictures, it will be informative...
PLA polymer ( Polylactic acid ?) is not soluble in water, you can disperse in water and drop cast, spin cast is not necessary other candidates are CHCl3 , DMF, CH₂Cl₂ , even coarse and aglomorated particle can be observed, it will be hard to find a good spot for imaging, but it will give some pictures.
alternatively you also can use SEM/EDS mapping to identify the particles and their distribution
Yes Prof. you got it right, but the thickness of polylactic acid/MgO nano-composite films is 80 um (micrometer not nanometer). Yes, I need to transfer these films on TEM grid to study fine dispersion of nano-particles in planar direction.
I have gone for the FE-SEM but hardly could see the nano-particles (particle size ~60nm). Few FE-SEM micrographs are attached for your kind perusal.
Of course 80 micrometers film is too thick for TEM and you do need ultramicrotome. After proper embedding your film can be cut in any direction you wish. I would caution about observing only planar sections - distribution of particles could be different in the middle of the film and near its surfaces.
As for your 1-859 micrograph, I believe what we see is a surface contamination, not particles you are looking for.
Lots of thanks Prof Dusevich and Prof Kirakosyan for your valuable time and suggestions those are really helpful to a young researcher like me.
I agree with your point that I should study both planar and cross-sectional direction for the nanoparticle distribution. the only constrain I have is ultramicrotomy of the sample in either direction. Prof may I ask you to further enlighten the process of ultra fine cutting of the thin films using ultramicrotomy or share any manual which I could refer for the same.
You can use various embedding resins, for example Embed 812 from https://www.emsdiasum.com/microscopy/technical/datasheet/14120.aspx or many other EM suppliers. Use flat embedding mold. Place your film on the floor of a mold, so that you will know film orientation after embedding. This specimen can be used for cross sections. For near planar mode you can cut the same block under shallow angle (like 15 degrees). For true planar sections you need to cut small piece from your block so you can reembed it with right orientation.
Many thanks Prof. for your valuable time and suggestion. I will sure try this.
Best regards.
Dear, Chetan Swaroop i misread the 80um as 80nm, some of my recommendations would be not the case, sorry for this, perhaps the only way to is ultramicrotom, any kind of epoxy resin will work. in my case i had to investigate cross-section of 50-100 nanometer film of PMMA which has same colour as epoxy resin and it is impossible to identify the film, so initially I deposited metal film, like Pt in sputtering machine (commonly used for SEM sample coating), after that its easy to identify the sample. in you case, as you need to trim the sample in planar direction, just make sure the resin matrix you use has good adhesion to your sample.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Composites
- Nanocomposites