I need to coat a polymer layer on ITO coated glass substrate upto micrometer scale, how to achieve this, please guide. Yellow layer in figure shows the polyamide layer.
Thank you!
Deepak Kararwal No figure attached. 5 microns of polyimide is a very thick layer. In my experience in the LCD industry then 300 Angstroms was fine for a surface to rub to align nematic LC's. Best way of coating would be spin coating (Headway spinner) as this gives the most uniform layers but you may need a number of these layers to make 5 microns and the interfaces can be problem. Dip coating is an alternative. Again, even if your starting concentration is high (in a solvent such as DMF or NMP) you may need multiple coatings to get to 5 microns. Out of interest, 2 questions:
- Why do you need 5 microns?
- How will you measure this thickness? Do what degree of precision s required? 5 +/0 0.1 microns? Better or worse?
Deepak Kararwal There are two methodologies to obtain 5 micrometer i.e. spin coating and Doctor blade method. For spin coating you can use 50 mg of powder in 5 ml of DMSO (or other solvent) to form a slurry then you can deposited that slurry on FTO glass with a initial spinning rate of 500 rpm for 5 s and then 3000 rpm for 10 s. Then dry the film at 120 C for 20 min. this way you will be able to obtain one layer, so you can repeat this method for many times to obtain your concern structure. for doctor blade method you can watch this video https://www.youtube.com/watch?v=v9va5WENUQw
hope it will work
Dear Deepak Kararwal, I think for such a film thickness, a simple spray coating may do the job. Please have a look at the following free download paper. My Regards
https://doi.org/10.1016/j.procir.2014.02.046
If you have the spin coated rotate table by varying the speed of rotation you can covered by polymer layer with determined thickness.
The other way is using the Langmur-Blodjet bath for coverage realizing on the small samples because their sizes are limited by the sizes of bath.
However, may be sufficient will be coating in large volume bath with polymer. Because, such sizes are the same as automobile's paint coverage.
Dmitry Milovzorov Langmuir–Blodgett is spelled thus. We need to remember too that Katharine Blodgett did all the actual work and Langmuir tried to claim credit for all of this. See: https://en.wikipedia.org/wiki/Katharine_Burr_Blodgett
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