I made an UF membrane with 22 wt% of PVDF polymer and 5 wt% PEG200 in the casting solution. The dope solution was viscose. Some irregular lines are observed on the surface SEM micrograph. Are they polymer chains or its a casting knife effect?
Do you expected smooth and clean surface!!!!!!!!!!!!!!!!!!
It`s the regular Thin films roughness.
Well, during phase inversion process when the polymer is solidifying we generally obtain uncontrolled textures. You may neither call these lines are particularly PVDF chains nor they can be the knife effect. Yes it can somehow be related with the cleanliness of the glass plate you used during casting OR the chemical interaction between the solvent and polymer. Moreover, i guess your membranes are also thick, this can also be a reason. I have attached herewith my PVDF (0.6mm thick; prepared in DMSO).
i ll be happy to discuss more if u like.
Dear Waqar,
Thanks for your time and help. The lines in my view were polymer chains. Because the PVDF concentration is high (22 wt%) and there is lots of PVDF chains in the membrane matrix and also on the surface. The wet membrane thickness is 200 micron.
Regards
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