Selcuk, please read my various comments: a) HCl is the worst you can choose b) about temperature and oxidant addition time ...
you can find a lot of publications on my RG pages. The best is, to run PAni polymerisation at lower temperature, with good cooling ad slow addition of oxidant. Please note that HCl is the worst counterion (doping acid) you can choose.
Dear all;
following two attached files dealing with the low temperature polymerization of PANi. Regards
my comments to these papers:
a) HCl is the worst acid one can choose to use because of some side reactions (some Cl is covalently bound into the PAni chain, you can check this by analyzing the Emeraldine Base after neutralizing the PAni Emeraldine salt, check the Cl content after repeated neutralisation and washing!
- best acid is p-Toluene sulfonic acid
b) the addition of the oxidant should be much slower than it was described in the 2 papers
c) no need to run at -20 or - 25 degrees, slightly above 0 degrees is already ok.
Polyaniline is best synthesized using aniline monomer in aqueous medium in the presence of DBSA, PTSA, camphor sulphonic acid and other organic acids at 0oC -2oC by using oxidant like ammonium per sulphate. Care has to be taken to add APS drop-wise otherwise oligomers will be formed. DBSA is a preferred medium of polymerization because it acts as dopant as well as surfactant. Wessling is right that HCl is not used as medium of polymerization because the PANI synthesized is not thermally stable and even chloride ions are not friendly dopants.
DBSA-dodecyl benzene sulphonic acid; PTSA - p-toluene sulphonic acid
for DBSA, please be aware that the resulting PAni is easily dispersible in water which means, you can not easily recover it from water reaction medium = ot easy to remove the oxidant by-products / salts; moreover, with DBSA, the resulting conductivity is much lower. As I said before: pTsA is preferred.
Dr. Wessling, for removing excess of DBSA, once polymerization is over, wash it with isopropanol and after that isopropanol+water solution, that way filtration can be easily achieved.
I know how to run this, we have real products out there in the market based on PAni-DBSA. The only what I say is it is not as easy to clean as the pTsA doped one.
Selcuk, please read my various comments: a) HCl is the worst you can choose b) about temperature and oxidant addition time ...
You can find a publication on my RG page and other is IUPAC paper entitled as "Polyaniline: preparation of a conducting polymer"
or try this standard method for synthesis of Polyaniline
In one beaker make the 50 ml solution of 1.0M HCl and add 0.2M aniline into it. In another beaker make 0.25M solution of ammonium persulphate in 1.0M HCl. Keep both solutions for 1 h at room temperature (~18–24 °C), then mixed in a beaker, briefly stirred (magnetic stirring), and left at rest to polymerize. Next day, the PANI precipitate was collected on a filter, washed with three 100 ml portions of
0.2 M HCl, and similarly with acetone. Polyaniline (emeraldine) powder was dried in vacuum at 80 °C for overnight. Next day crush it and your material is ready for further studies.
Pallavi, please read my various comments: a) HCl is the worst you can choose b) about temperature and oxidant addition time ...
Wessling is right. HCl has to be avoided. Have some concern about benzidine when aniline is synthesized in HCl medium at room temperature. Rate of addition of oxidant and temperature plays a major role. Oxidation potential of ammonium persulphate is 2.0 V and of aniline 0.8 V. So care has to be taken when synthesis of aniline is carried out.
yes???? you can synthesis PANI in room temperature under optimal condition ( 1M HCl ,1g APS or PPS and 5.1g of Aniline.
you can see my work in research gate or polymer bulltin springer.
thank's
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