I guess that you deposit from the aqueous acidic solution? What regime do you use? E.G.: constant potential, constant current, or potentiodynamic scanning ?

You can play with: increase of the aniline concentration, increase of temperature and increase of the voltage sweep rate if the later mode is used (it would be my first choice). Do not increase the oxidation potential as this leads to polymer irreversible degradation.

The following trick can help as well:

1. Deprotonate film with the ammonia solution.

2. Wash out short polymeric chains and oligomers with methanol.

3. Remove methanol with dierthyl ether and dry the film.

4. Re-protonate it by immersing in acid.

Finally, you can consider the chemical synthesis of the soluble form of PaNi. If you are interested in this let me know I'll dig a bit for an exact description of the procedure.

Thank you all for your help! Yes, I´m using the aqueous acidic solution and doing potentiodynamic scanning. Ill try your suggestions. It may be helpful trying the chemical synthesis. Thank you!

if you want to increase the response time of aniline, I suggest depositing the polymer in porous membranes such as anodic aluminum oxide and poly carbonate membranes, both sold by Watson. They are normally used as filtering membranes but they are extremely versatile. If you electrochemically deposit a working electrode on one of the membrane, stick the membrane in a solution of aniline and apply the appropriate oxidation potential, you will get growth inside the membrane. The increase aspect ratio of the aniline growth in the membranes will increase your retention time by orders of magnitude. Sang Bok Lee's group from the U. of Maryland's Chemistry department has published multiple papers on using this technique on Ppy and PEDOT which you should check out.