@ Peetam Mandal

You did not understand the thing you are trying to talk about. Why was you posting? Bad "advise" is much worse than no advice at all.

@ Gustavo do Carmo

Make a suspension as was advised by Vijayshankar Asokan, then put a drop of it on some smooth surface (glass or plastic, but then you'll need to coat, or polished metal, no coating required). No problems should be with observation of multiwalled tubes. Single wall nanotubes are more difficult to observe with SEM, and sometimes it is better to use agglomerated specimen. You may find nice tube sticking out of a clump.

Ultrasonic bath, it sould be enough

Disperse the nanotubes (i guess you have it in powder form) in a volatile solvent (ethanol) to prepare a very very dilution dispersion. Few minutes of ultrasonication is required.

@ Peetam Mandal

You did not understand the thing you are trying to talk about. Why was you posting? Bad "advise" is much worse than no advice at all.

@ Gustavo do Carmo

Make a suspension as was advised by Vijayshankar Asokan, then put a drop of it on some smooth surface (glass or plastic, but then you'll need to coat, or polished metal, no coating required). No problems should be with observation of multiwalled tubes. Single wall nanotubes are more difficult to observe with SEM, and sometimes it is better to use agglomerated specimen. You may find nice tube sticking out of a clump.

Thank u @Vladimir Dusevich , @Vijayshankar and @evngeny for all advise.

The last time I've made an analysis of a nanotube, the higher magnification that I've made it was 15.000x even adjusting the ol aperture, lens alignment, wd, pc and etc...the higher magnification was 15.000x.

My equipment it's a jeol jsm it 300

I am not familiar with your SEM, but I would try first lower voltages (3-5 kV), then higher voltages (like 15 kV). Check microscope resolution (with standard specimen, gold or tin particles) if needed. As a last measure - coat specimen with heavy metal (like Ag-Pd) for better contrast.

You can also increase the contrast of the image by using a metallic (eg gold) substrate (spray it) and then depositing the suspension obtained by ultrasonic dispersion as previously advised Vijayshankar Asokan.

Disperse the tubes in 30% Triton-x/70% ethanol, sonicate lightly. Dropper onto carbon tape on the stub. This should do the trick, keep the kV low, kV 10-30 also. I have had great results either way, just depends on how you want to see them. Sputtering is unnecessary, you can even dropper the solution directly onto the stub wo C tape and see how that goes. Most CNTs are conductive depending on the chirality. It is mostly trial and error.

Thank guys for all the tips given here!!! It helped me a lot!