The O2/H2O redox couple as the origin of the structural/electronic defects in polyanilines
| Autor: | A. Régis, Ph. Colomban, A. Gruger, A. El Khalki |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Aqueous solution
Stereochemistry Mechanical Engineering Metals and Alloys Backbone chain Protonation Condensed Matter Physics Oligomer Redox Electronic Optical and Magnetic Materials chemistry.chemical_compound chemistry Mechanics of Materials Oxidation state Polymer chemistry Polyaniline Materials Chemistry Amine gas treating |
| Zdroj: | Synthetic Metals. 139:175-186 |
| ISSN: | 0379-6779 |
| DOI: | 10.1016/s0379-6779(03)00126-7 |
| Popis: | The protonation of N , N ′-diphenyl-1,4-phenylenediimine (BQB oligomer, representative of the polyaniline (PANI) unit) by H 2 SO 4 and non-oxidative acids like H 3 PO 4 , HCl and CH 3 COOH is studied by UV-Vis–NIR and resonance Raman spectroscopies. Emphasis is put on the water content effect. The acid-solubilised BQB is reduced to the amine oxidation state: in diluted acids, protonated (BBB) 2+ species are formed while a mixture of radical cations and protonated (BQB) 2+ species is observed for higher concentrations. The results show that redox reactions involving the O 2 /H 2 O couple are present as side-reactions. In concentrated HCl acid, the presence of protonated (BBB) species chlorinated on the ring indicates that the Cl 2 /Cl − redox couple participates to the redox phenomena. Side-reactions randomly affect the quinoid or the benzenoid segments of the polyaniline, changing the backbone chain linkage during EB and ES synthesis. This prevents ideal linking for the final ES material and the resulting materials failed to achieve the intrinsic conductivity expected for ideal ES products. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect