This is the procedure we use in our lab:

1-

Normally you need to grab a TEM grid (typically carbon coated-formvar on cooper) and place it on the tip of a very sharply pointed tweezers. The grid must be grabbed by the tweezers only o the circular frame. Avoid crossing onto the square grid zone with the tips of the tweezers.

The grid must be clamped on the tweezers using a 1cm piece of silicone tubing on the handle of the tweezers. The silicone tubing should be placed on the tweezers near the opposite end of the tips and once you grabed a grid, slide it towards the tip which will clamp the tweezer and hold the grid.

Alternatively there are self-clamping fine tip tweezers you can order.

2

Once you have the grid clamped inspect it so you can detect the carbon coated side. This side looks bright and blackish, while the other side looks more like a dull copper finish.

The sample must be placed on the carbon side.

3

Leave the clamped grid on a clean zone, over a clean sheet of paper, and cover the whole with a large crystalizer or large petri dish to prevent dust.

4

Then cut a small triangle or wedge of filter paper, with a very sharp tip. (typically an isosceles 3cm long, and 6mm at the base.

5

Using a clean tip, and a pipetor, load 10microliters of the suspension of nanoparticles. Place a drop on the grid so it forms a dome that covers the entire grid. Make sure the liquid does not go between the tweezers tips.

6

Wait 10 minutes. For particles to adsorb onto the grid.

7

Very carefully, touch the edge of the grid with the very tip of the paper wedge. The wedge will absorb most of the liquid but leave a thin layer still on the grid.

8

Let the liquid film dry completely by evaporation. (30 min tipically)

9

Take the grid and place it on a grid carrier.

Notes:

Having several tweezers helps to make many specimens. But mark the tweezers with a permanent marker first and make sure you write down what solution you put on each tweezers number.

If the solution contains very dilute nanoparticles place one droplet and let it completely dry.

If the solvent is not water, specially if it is very volatile, it may be best to just place one droplet and wait until it dries.

Some solvents may dissolve the formvar, and then you get a grid submersed in a spherical droplet of liquid. In this case the imaging results in the TEM are not good. Avoid this. Read the specification of the grids you use.

Good luck

This is the procedure we use in our lab:

1-

Normally you need to grab a TEM grid (typically carbon coated-formvar on cooper) and place it on the tip of a very sharply pointed tweezers. The grid must be grabbed by the tweezers only o the circular frame. Avoid crossing onto the square grid zone with the tips of the tweezers.

The grid must be clamped on the tweezers using a 1cm piece of silicone tubing on the handle of the tweezers. The silicone tubing should be placed on the tweezers near the opposite end of the tips and once you grabed a grid, slide it towards the tip which will clamp the tweezer and hold the grid.

Alternatively there are self-clamping fine tip tweezers you can order.

2

Once you have the grid clamped inspect it so you can detect the carbon coated side. This side looks bright and blackish, while the other side looks more like a dull copper finish.

The sample must be placed on the carbon side.

3

Leave the clamped grid on a clean zone, over a clean sheet of paper, and cover the whole with a large crystalizer or large petri dish to prevent dust.

4

Then cut a small triangle or wedge of filter paper, with a very sharp tip. (typically an isosceles 3cm long, and 6mm at the base.

5

Using a clean tip, and a pipetor, load 10microliters of the suspension of nanoparticles. Place a drop on the grid so it forms a dome that covers the entire grid. Make sure the liquid does not go between the tweezers tips.

6

Wait 10 minutes. For particles to adsorb onto the grid.

7

Very carefully, touch the edge of the grid with the very tip of the paper wedge. The wedge will absorb most of the liquid but leave a thin layer still on the grid.

8

Let the liquid film dry completely by evaporation. (30 min tipically)

9

Take the grid and place it on a grid carrier.

Notes:

Having several tweezers helps to make many specimens. But mark the tweezers with a permanent marker first and make sure you write down what solution you put on each tweezers number.

If the solution contains very dilute nanoparticles place one droplet and let it completely dry.

If the solvent is not water, specially if it is very volatile, it may be best to just place one droplet and wait until it dries.

Some solvents may dissolve the formvar, and then you get a grid submersed in a spherical droplet of liquid. In this case the imaging results in the TEM are not good. Avoid this. Read the specification of the grids you use.

Good luck

Thank you a lot

Sonicate your powder in a solvent to get well dispersion, using copper mesh catch some particles from the suspension, then examine it under TEM.

Thanks to all. To hold of magnetic metals and their oxides on copper grid we have used 1% solution of nitrocellulose in amylacetate.

You should preparing sample very crefully. The TEM image quality sometimes depend on the sample preparation. So, firstly you can take a little bit amount of metal and metal oxide nanoparticles and then disperse in ethanol and use ultrasonication method for five min sonication. After that the nanopartical mixing solution put on TEM grid (typically carbon coated-formar on cooper) and then dry in atmosohre. After drying the TEM grid is placed at the center of sample holed. After making high vacum TEM images you can take for your required.

So, what we did

1. 0.2 g of material was placed in a plastic cell and mixed with 1 ml of ethanol

2. The cell was treated in an ultrasonic bath for 10 min to destroy the aggregates

3. The cell was placed in a centrifuge for 5 minutes 4,000 rpm

4. Using a pipette, 0.1 μl was taken from the top layer and the one drop was put onto a copper grid coated with carbon. The drop was dried.

5. A magnet was brought to the surface, to remove loose particles

Another option was tested instead of point 5 - is to cover grid by 1% solution of nitrocellulose in amylacetate. But you should do it very carefully and do not put much of this solution.

For very thin and flat nanoparticles of Ni we had to use STEM instead of TEM.

Dear Dr. the following site may be useful for you

https://www.researchgate.net/post/What_are_the_steps_in_preparing_TEM_specimens_of_various_nanomaterialsmetal_Metal_oxide_and_polymer_using_Langmuir-Blodgett_LB_method