Dear Nathan Samples,

Try to make very dilute solution of polyaniline nano fiber in NMP. If you find difficulty small amount of LiCl can be added. which can enhance PANI solubility. Then fiter and sonicate for some tme. This solution if you spin coated, you can get uniform film. Remember,.. concentration of the solution should be very much less inorder to get uniform film. best of luck dear friend.

this is not a solution, but a dispersion. Please look at my article "polyaniline - solution or dispersion?" (you can already see - why sonicate? forming solutions does not require sinocation, forming dispersions is very often enhanced by sonication)

The pellet conductivity and film conductivity are different. The effect of solvents are to be taken into account. Please refer the book electrical and optical polymer systems (Editor - Donald L Wise). Conductivity of PANI films depends on the chain conformation as a result of the type of dopants, solvent, etc. For practical applications, films are desirable in many cases. The repeatability in pellets is not that perfect !!! There are too many articles for casting good films of polyaniline. A google search will do. Most of the articles came in synthetic metals (1990s)...

One way is to de-dope PANI and then re-dope using CSA by mechanical mixing. Then dissolve (Bernhard would never agree to the word 'dissolve': Apologies) in m-cresol by magnetic stirring. Filter using a micron filter. You have to optimize the ratio of de-doped PANI: CSA and m-cresol for getting good film and appreciable conductivities.

You can make it by spin coating or dip coating techniques. You have to play with the concentration of the solution.

You can use liquid liquid interface reaction technique to deposit polyaniline thin film on suitable substrate or langmuir blodgget technique also usefull in this case.

Excellent thin films can be made by spin coating the solution of CSA re-;doped PANI in m-cresol. Drying the film in vacuum oven for about 24 hours is required to remove the excess solvent..

You could try to immerge vertically a cilinder like an essay tube in the solution one or more times, letting it to dry each time. Maybe in this way the film formation will be formed more uniform. After obtaining a sufficiently thick film on the cilinter, you can try carefully to cut a strip for your measurements.

although somewhat tired to repeat, but I would like to mention again, that polyaniline can not form true solutions. Please look at my article also available here in RG "conductive polymers - solutions or dispersions"?

For formation of thin layers of polyaniline on almost any substrate can easily be made if you runb a polymerisation of aniline in presence of your substrate.

You can try LB deposition of PANI on glass substrate and study the conductivity. Further you can choose the no. of layers too.

electrochemical polymerization on ITO glass

chemical polymerization, use DDNNSA as the counter ion

Dnnsa

I have experience in preparing "high solids" (it's a relative term, you know--can get >10% PA solids in the dispersion) conductive PA dispersions by a unique, proprietary method. We tried hundreds of materials to get useful Pani dispersions, and found only one that was suitable. Can also add other materials, such as other non-conductive polymers, to improve surface compatibility with various substrates. I addition, small amounts of highly conductive carbon can be added to "tune" the resistivity. When applied to various polymer substrates, the EMI shielding effectivenss was nearly as good as copper metal. Some research was also conducted with these dispersions for improving properties of tantalum chip capacitors. Thin films were also prepared on glas, PET, etc., from a bit more dilute dispersions. Of course, they have a green cast, but are thin enough to have >70% optical transmission. Used to prepare some highly prototype circuits on PET with LEDs.

I can tell you from working with NMP, you want to avoid it. It is essentially impossible to remove it all without compromising the Pani film. And the residual NMP will interfere with your tests. Try replacing NMP with butyrolactone. I did not try it with Pani, but with several other difficult to dissolve polymers, butyrolactone was a useful replacement for NMP. It takes longer to dissolve/disperse the solids--sometimes a few days--but it is a lot easier to strip the butyrolactone. (And no, butyrolactone is not that one suitable vehicle mentioned above for the Pani dispersions.)

Keep in mind that whatever you are doing in the lab, it doesn't matter how good the conductivity is, if you cannot find a process for preparing and applying it that is COMMERCIALLY viable, you will have nothing but a nice lab project and maybe a publication.

I don't know if you can contact me via RG. If not and you are interested in pursuing this, leave a reply and I'll arrange to make contact.

Thank you guys for all the suggestions. I haven't been able to try anything else in a while but next time I do I have some great information

Below is a reference to preparing conductive PANI and its application and use as a transparent electrode for polymer dispersed liquid (PDLC) crystal application. I have experience with these materials, both in the flexible applications and for non-flexible applications such as smart windows (utilizing commercial window glazing for the rigid surfaces).

"A new method for the preparation of conductive polyaniline solutions: Application to liquid crystal devices"

Advanced Materials

Volume 8, Issue 12, pages 994–997, December 1996

I found out a method by which u cn develop excellent quality thin film uniform in nature. Simply u make 2 solution a monomer and other APS solution >> both acidic , Drop cast monomer 1 drop on glass followed by a drop of APS and before start of polymerisation(that is color change) keep a glass slide on it at once. and remove after some time (you will have to play) . I gurantee u will get excellent quality film.

Yogesh P Gawli is it okay for direct polymerization? PANI needs to polymerize at a low temperature right?