prepare PANI by as usual method,then filter on Nitrocellulose membrane ,then put the Nitrocellulose membrane containing PANI into Acetone bath,Nitrocellulose membrane will dissolve in Acetone,so you can get free standing film.

Note:Flexiblity will be depend on your concentration of PANi.

Mr. K.P. I thank you for your Idea.

But I doubt that the well dissolved PANI (in NMP) solution will pass through the pores of the membrane under filtration. The membrane may be able to collect only its agglomerations.

Thus, what I am looking for is a free standing film after casting.

This paper describes a method to form a free-standing composite film of PANI with carbon fibers, perhaps it can help:

http://pubs.acs.org/doi/abs/10.1021/cm1012153

I mixed PANI base polymer with camphor-10-sulfonic acid at 2:1 ratio, crushed and mixed them well. I used m-cresol (3wt%) as a solvent to dissolve the mixture.(just try to keep the level of your solvent upper then your powder)

Then sonicated for 3-4 hours. Then made PANI thin layer on Glass substrate by spin coating method. It was conducting and showed green color layer. Hope it will help you. If you need further information please inform me.

starting from PAni base polymer will never deliver really homogeneous (= homogeneous on nano scale!) results. PAni consists of ca 10 nm small nanoparticles, if you add the CSA, then it has to diffuse into these particles, it does not end up in a homogeneous compound.

Please be aware that also m-cresol can not *dissolve* PAni, even nit PAni base.

You can find more here:

https://www.researchgate.net/publication/253651172_Conductive_Polymers_as_Organic_Nanometals

and in other of my publications. Comments and questions are welcome.

Chapter Conductive Polymers as Organic Nanometals