From: psphicas@pipeline.com (Eleana Sphicas)

Does anyone have a reliable way to make carbon-coated grids for high resolution work?
I have tried floating carbon films off mica-- they seem to fall apart before I can pick them up on grids.
Any tips or suggestions?
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From: Ian MacLaren (MACLARIZ@novell2.bham.ac.uk)

The method we use here is as follows (as learnt from our TEM technicians):
1) Place a drop of washing up liquid or teepol on a glass slide and wipe it all over with some tissue paper wiping most of it off in the process (leaving the slide sightly sticky).
2) Form a thin carbon film on this slide in a carbon coater.
3) Score the carbon film with a razor blade or scalpel to suitable size pieces.
4) Float off the pieces of carbon film with water and catch with copper grids.

I usually prefer 200 mesh grids and it works fine every time. I use them to support small ceramic particles in the TEM and they usually behave very well up to at least 250k magnification.
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From: "John W Heckman" (heckman@pilot.msu.edu)

I've used two ways to fabricate carbon coated grids.
Plan A. Much as you have done. Generally it seems better to make the carbon film on the mica surface quite thin, something around 10nm (sorry my only monitor is mounted in a freeze-fracture machine so I can't more than speculate on how thin). Score the resulting film into about 4mm squares, float on dH2O, and pick them up on flamed grids. Blot at the edge to dry.

Plan B. Make conventional plastic film coated grids, by whatever means are at your disposal, and pick them up from above on clean paper. Allow to dry then carbon coat. Put the coated grids (film side up) into a chamber made from (e.g.) a glass petri dish ca. 90mm in which there is a pad of filterpaper soaked with a solvent of the film plastic. I usually let them sit over night but the plastic is likely gone and diluted into the solvent more quickly than that. If you want them real clean you can repeat with a fresh chamber assembly. Also makes really nice holey carbon if you start out with glycerol doped plastic.
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From: Peter Ingram INGRAM@RTI.ORG
I would NOT RECOMMEND the use of Teepol or any other commercial washing-up liquid for the preparation of carbon films for ANALYTICAL studies using EDX or EELS - especially with biological specimens where one is interest- ed in serious elemental quantitation!
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From: gwe@biotech.ufl.edu (Greg Erdos) )We routinely float carbon from mica and mount on sticky grids.( Treated with "grid glue").
After cleaving the mica, I cut it in 3-4 mm wide strips, evaporate the carbon by a resistance method (very important),. Then I clamp the strip carbon side up in one pair of tweezers, then I grab the other end and cut off a square of mica. I float it off in a white porcelain spot plate and pick it up on the grid, being careful to always blot from the side.
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I have had several questions about what I mean when I refer to resistance evaporation. If current passes directly through the carbon source and thus heating it, this is resistance evaporation. So if one is using carbon thread or a pair of carbon rods that touch, you are using electrical resistance to generate the heat.
The alternate method is electron beam evaporation where the carbon source is positioned in the center of a tungsten coil, but not touching it. When current is applied to the tungsten under vacuum, electrons are produced which then bombard the carbon and thus evaporate it.
Sorry for the confusion.
Greg Erdos
E-mail: gwe@biotech.ufl.edu
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From: Daniel Possin (oemlab@u.washington.edu)
Is there a reason why you cannot evaporate carbon on to collodion coated grids? The collodion quickly sublimes in the beam creating a very clear window to look through. I doubt that it would be much better with a floated film and the coating would probably be more beam stabile.
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I'll take issue with Dan above and say that floated films ARE far better.

The Wiz
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