Acetonitrile is suitable to solubilize the monomer (pyrrole) but the polymer itself is NOT considered particularly soluble without being derivatize : Article Solvent effects on the characteristics of soluble polypyrrole
I agree, this is a problem. But it depends on a dopant. If PPy is doped with Cl- there is no possibility to dissolve: 10.1016/j.chroma.2013.03.065 .
If it is surface active dopant like dodecylbenzenesulfonate (DBS) the situation can be improved Article Synthesis and characterization of soluble polypyrrole with i...
or
Article Synthesis and properties of soluble polypyrrole doped with d...
Dear all, most if not all casual conducting polymers are insoluble in their neat polymeric form, at best they form a kind of dispersions. Dr. Bernhard Wessling has many contributions on this matter within RG, I strongly advise you to look for them to get a complete insight. My Regards