Hello.
I'm trying to synthesize the polyaniline emeraldine salt but there are some problems. Its color turns green to black (or dark blue) after washing and drying.
I got a green (dark green) solution after polymerization for 12h. At the moment I pour the methanol, the solution turns black. (At first, It seems to keep dark green.) After the vacuum filtration, I put the powder in the vacuum oven at 60℃. Then, It shows the powder of dark blue color. Can anyone find the cause of my problem? The overall process is below.
-I use aniline as monomer, DBSA as organic acid and surfactant, and APS as initiator.
- I make homogeneous dispersion of DBSA in DI water and add aniline while stirring.
- The solution become white and then I add APS.
-I get green (dark green) solution after polymerization for 12h.
-Then, I pour the methanol (equal volume to the polyaniline solution) to stop the further
polymerization and to wash the solution.
-I filtrate the solution with methanol and DI water several times and dry in vacuum at 60℃.
-I get the blue powder.
Is it a problem of the amount of methanol? or Should I stop adding the methanol at all? What is the best way for rinsing?
Any opinion would help. Thanks.
Dear Won,
Please minimize/optimize the amount of Methanol. Also, take-care about the amount of indicator. Sometimes excess indicator creates problem.
The best thing, you can contact Dr. Amrita De Adhikari. She is working on the same since last 6 years .
Santosh K. Tiwari
Thank you very much.
Before I try as you said, I want to ask something.
Does the indicator mean the initiator APS?
Santosh K. Tiwari
Thank you Santosh. I solved the problem. There are still minor problem to be tuned, but I think I found the key. You saved me! :)
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