Wang WeiKe, you first need to produce a fine powder of a doped Polyaniline, I suggest to use para-toluene sulfonic acid (not HCl, because HCl forms covalent bonds with PAni and makes it inhomogeneous).  (You can find some polymerisation procedure in some of my patents)

Then you neutralize very intensively with NH4OH, wash and wash and wash and wash, finally wash a lot with DI water.

Then you disperse the neutralized Emeraldine Base powder in NMP, you take no more than 0.2 % EB, sonicate well until you have a dispersion with no particles. Then you deposit the film, dry well, and dope it.

You can use the dip coating method via the dipping of the substrates in the solution before polymerization. After the polymerization, the polymer powder will be formed and the polymer film will be formed spontaneously on the substrate

It would be not a question for deposition of polyaniline on the substrate, the problem is, however, how to make it firmly adhere to the surface.

In my opinion, the monomer, small amount of aniline should firstly bonding or anchoring onto the substrate, and then further polymerization with free aniline.

Polyaniline has least film-forming tendency. One of the easiest way to do d same is to incorporate them in a polymer matrix like polyvinylalcohol, PMMA etc.

Another way is de-dope it to EB form, re-dope with CSA and then dissolve it in m-cresol. It takes quite a long tie to fully dissolve. But you can see the process as soon as you start stirring the PANI-CSA mixture. Filter it with 0.45 micron filter. Quality thin films can be made from this solution either by spin coating or by dip coating. This has been experimentally done by me many times.

You can synthesis polyaniline in the presence of cationic surfactant for example, CTAB or cationic gemini surfactant. It will be suitable for spin coating.

soluble in concentrated H2SO4

If you need a very thin film but strongly adhered, try the electrografting of NSA. Then you can add aniline and obtain chemisorbed PANI.

I would like to remind everybody that Polyaniline is definitely insoluble. However, you can make films when preparing well defined *dispersions* (= nanoparticle dispersions in suitable solvent mixtures). Ormecon has prepared a lot of different dispersions for preparing free-standing films or thin layers on various substrates which show good conductivity (up to several 100 S/cm) and good adhesion.

for discussion of solubility (better: "non-solubility") please read this:

http://www.bernhard-wessling.com/pani/www2/Research/soludisp/Welcome.html

From this abstract, you can access the various article chapters. The article was finally published in a H.S. Nalwa Handbook.

The most precise thin film of polyaniline (100 nm and less) may be obtained by the method of electropolymerization of aniline on the thin gold layer obtained by the evaporattion of the gold on the glass in vacuum.

Also, take a look at "vapour phase polymerisation" (VPP) method. it really is an easy and convenient way to deposit very thin layers of conducting polymers onto various substrates. Sometimes they call it vapour phase deposition, oxidative chemical vapour deposition, etc. You can start by following research in Gleason group (MIT):

http://web.mit.edu/gleason-lab/research.htm

Furthermore, using this way, you will not be worried about the controversial "true solution or dispersion" issue of ICPs any more, since you won't need a solvent for your ICP thin film deposition!

The most precise thin film of polyaniline (100 nm and less) may be obtained by the method of electropolymerization of aniline on the thin gold layer obtained by the evaporattion of the gold on the glass in vacuum.

Quality of polyanilne film may vary according to your requirement and so is the technique to be used. I worked on little thick film of less than mm value and prepared by solution casting method in an air oven.

Here in attached publication is alternative technique for PANI synthesis based on application of redox enzymes:

Article Enzymatically synthesized polyaniline layer for extension of...

Like this？somewhat 20μm

Dengtai Chen, Is it a pure PANI film? Is it a published result that I can access?

Chen DengTai made a film consisting of neutral PAni (Emeraldine base), not conductive, from a dispersion of PAni-EB in NMP. The film can be rendered conductive by doping with acids, however, such doping is not homogenous.

Sreekanth and all, you may be interested to follow this collection of links where you also can find something about how to make highly conductive films, however, I need to make you aware: this is everything else than simple.

https://www.researchgate.net/publication/260427241_Milestones__highlights_of_the_Organic_Metal_Polyaniline_Science__Technology?ev=srch_pub

Look for where I link to highly conductive films.

Also this publication maybe interesting to you:

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

Article Milestones & highlights of the Organic Metal Polyaniline Sci...

Chapter Conductive Polymers as Organic Nanometals

I think the simple method for thin films of polyaniline is electrochemically method using cyclic voltammetery

 Dengtai Chen,  Is it a published result that I can access? Can you give me a link about the paper with your method?

Bernhard Wessling, I want to get the pure polyaniline film, and then dope it with HCl ,how can I get it? Do you know the way of Dengtai Chen?

One more related publication

Article Gold Nanoparticle and Conducting Polymer – Polyaniline – Bas...

Wang WeiKe, you first need to produce a fine powder of a doped Polyaniline, I suggest to use para-toluene sulfonic acid (not HCl, because HCl forms covalent bonds with PAni and makes it inhomogeneous).  (You can find some polymerisation procedure in some of my patents)

Then you neutralize very intensively with NH4OH, wash and wash and wash and wash, finally wash a lot with DI water.

Then you disperse the neutralized Emeraldine Base powder in NMP, you take no more than 0.2 % EB, sonicate well until you have a dispersion with no particles. Then you deposit the film, dry well, and dope it.

Remyamol Thekkayil, Weike Wang

May I ask you both how did it go? what did you achieve?

what about the pani film making in m-cresol?

Can be done by spin coating?

yes

Dear All,

After depositing PANI on the GaAs substrate, how long should put the sample on the hot plate and how long, please?

You must be sure polyaniline is well solved in NMP. If it is well solved, colour of the solvent is blue like a blue ink. You cannot see any particle. You should clear substrate with solvents and etch an acid to allow interaction between them.

Hidayet Çetin sorry, I must correct you again so to prevent other readers to draw wrong conclusions: polyaniline can not be "solved" (you wanted to write "dissolved") at all, PAni can not form any true solution;

what you do with PAni (EB) in NMP, is to form a dispersion.

Bernhard Wessling, sorry, I must correct your answer, if you apply NH4OH, you can obtain soluble polyaniline!!

no, not any polyaniline form is truely soluble. With your answer, I can see that you did not seriously nor deeply study this question, but I did, please read this:

Chapter Conductive Polymers as Organic Nanometals

PAni-EB (after you used NH4OH) particle size is about 5 nm, but EB as well is not truely soluble, but nicely dispersible

Please pay attention to your words! If you know anything, you can share a scientific and kindly style but you should not underestimate anyone’s knowledge or experience about on a topic.

I am choosing my words very carefully. As you said " I must correct your answer, if you apply NH4OH, you can obtain soluble polyaniline!! " it told me that you can not have studied this carefully enough, that's what I said.

Otherwise show me your experimental evidence that you have differentiated your "solution" from what I have shown is in fact a dispersion.

I have published a guideline how to disprove my statements in the chapter which I have published many years ago and sent you the link to it:

Chapter Conductive Polymers as Organic Nanometals

Show me your experiments which could disprove my conclusions, and we share arguments again! Come on and do not express hollow words about "kindly style", just show the facts! (or admit that you did not have a true solution)

- did you at all read my paper before you sent the above answer? does seem so as the chapter requires some time before you finish reading and even more, before you finish digesting it.

José M. Campiña

Patent Intrinsically conductive polymer in the form of a dispersibl...

That alone is not sufficient, the following dispersion steps are also very complicate,

Patent Dispersions of intrinsically conductive polymers

so that I always suggest to go the other way, unless you want to do really long-term re-invention following my patents and publications.

I can not teach these complicate processes here via researchgate Q&A, impossible.