Try SEM rather than TEM in first instance. I would try and use freeze drying to remove the solvent as well. If the solvent is water watch out for ice crystal formation.

Best way to do this is to cool the sample in liquid ethane or propane rather than liquid nitrogen. Cooling rather than in liquid alkanes is a factor of 10-100 faster

Paul

thank you for your advice, sir. I have tried SEM already. But what I want to observe is lower than the resolution of SEM. Thank you for information of liquid ethane. I will try it someday.

In that case you may need to consider freeze fracture. Basically you need to rapidly freeze a drop of the gel (liquid ethane) slice the top off let some solvent evapourate then coat the sample with carbon and or platinum, float this replica off on to a water surface and then pick it up on the copper grid. It is a technique used fairly routinely in biology, you then ought to see small features, say 20 nm.

Ask around anyone you may know in the biology field to see if they have access to a freeze fracture machine

Good luck!

Thanks for your advice. I will try it.