why in FT-IR polyaniline: peak shift is different ? such as:
1- oxidant ( APS) Q=1560 cm-1 B= 1488 cm-1
but
2- Oxidant (FeCl3.6H2O) Q= 1554 B=1458
FeCl3.6H2O
I assume that your polyaniline is in ES form. Maybe it is due to the doping of counter ion? My previous work gives other peak position of Q structure.
Dear Zheng
why ion counter? Do you can explain more?
I don,t any ion counter in my reaction. i have oxidant an aniline.
The synthesis is carried out in HCl solution using APS or FeCl3 as the oxidant/catalyst. Both reactions give ES form PANI (half reduced and half oxidized), and should be doped with H+ and the counter ion to the doped site is Cl-.
However, depending on the catalyst, APS would produce SO42- counter ion, and FeCl3 would cause Fe2+ or Fe3+ doping of PANI. This products of catalyst would affect the vibration model of PANI (both Q and B structures), resulting in different IR peak positions. From my previous experience, the PANI need to be washed extensively with ammonia, then DI water and ethanol to dedope the strcture. Then you can dope it again using acid as you like.
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