Someone please advise how to get films of uniform thickness by solvent casting method. I am using petri dish to pour the PLA/chloroform solution but the thickness is not uniform.
Spin coating is the best way. You could try dip coating but it's usually not so good or controllable.
Thank you very much sir for your suggestion. Yes we do have spin coating machine but it is of smaller size than I require.
It depends on the viscosity of your solution and the viscosity of your solution will control the thickness of the film.If you want films with a very thin thickness(less than 100 micrometer), then prepare a 5to 10 weight percent of PLA solution in chloroform. then using a small beaker you pour the solution in your petridish. remember that your petridish must be on an even surface and this will control the uniformity of your film and also the way you pour the solution on your petridish,after trying a couple of times you get uniform films.
Thank you Madam. yes I think that level of the platform I need to check. I will also try it with the viscosity that you suggested. Thank you.
You're welcome. There is an application named "bubble".You can download that on your phone to check if the surface is even or not.
I used a wet film applicator (bird type: https://www.gardco.com/pages/application/ap/birdtypeapp.cfm).
Dissolved polymer can be evenly spread on a glass plate with this applicator which can be peeled out after drying, it helps in obtaining a highly uniform thickness of films. In my case wet film thickness was around 700 micron which produced 40-50 micron thickness films after drying. One can get this type of applicator from local vendors also. there are other variations of this kind of applicator.
You can google 'wet film applicatior' to find various suppliers or even can prepare it at your local workshop.
I purchased it form:
Samriddhi International Inc., Mumbai, India
Sandeep Nahata
Mb.No. + 91-730 3131 277
best wishes
The solution distribution with high homogeneity to prevent bubble of gas by controlling the RPM, ambient temperature which help to control the thickness of the film.
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