Protonation of Polyaniline in Hexafluoro-2-propanol. Spectroscopic Investigation

Irena Kulszewicz-Bajer , Ireneusz Wielgus , Adam Proń , Patrice Rannou

Abstract

Three principal forms of polyaniline, leucoemeraldine (LEB), emeraldine (EB), and pernigraniline (PNB), have been prepared, and their spectral properties have been studied in a newly discovered polyaniline solvent, hexafluoro-2-propanol (HFIP). In HFIP a significant hypsochromic shift of the absorption due to main electronic transitions is observed with respect to the analogous transitions in the spectra recorded for N-methylpyrrolidinone (NMP). In particular, the π to π* transition is shifted to 308 nm in LEB and to 305 nm in EB and PNB and the benzoid to quinoid ring excitonic transition is shifted to 502 nm in EB and PNB. In EB and PNB spectra, an additional peak at 800 nm is observed, which can be ascribed to the protonation of these forms of polyaniline by the highly acidic solvent. EB has been protonated in HFIP solution with three types of protonating agents:? camphorsulfonic acid (CSA), phenylphosphonic acid (PPA), and poly(hexamethylene phosphate) (PHMeP). Protonation in HFIP facilitates the formation of the extended coil conformation of emeraldine similarly to the protonation in m-cresol. The extended coil conformation favors in turn the delocalization of polarons. The degree of polaron delocalization, as judged from UV?vis?NIR spectra, depends strongly on the protonation agent, the highest delocalization being observed for EB(PPA)y.
Author Irena Kulszewicz-Bajer (FC / CPCT)
Irena Kulszewicz-Bajer,,
- Chair Of Polymer Chemistry And Technology
, Ireneusz Wielgus (FC / CPCT)
Ireneusz Wielgus,,
- Chair Of Polymer Chemistry And Technology
, Adam Proń (FC / CPCT)
Adam Proń,,
- Chair Of Polymer Chemistry And Technology
, Patrice Rannou - [CEA Grenoble]
Patrice Rannou,,
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Journal seriesMacromolecules, ISSN 0024-9297
Issue year1997
Vol30
No23
Pages7091-7095
ASJC Classification2505 Materials Chemistry; 1604 Inorganic Chemistry; 2507 Polymers and Plastics; 1605 Organic Chemistry
DOIDOI:10.1021/ma9706081
URL http://dx.doi.org/10.1021/ma9706081
Score (nominal)45
Score sourcejournalList
Publication indicators Scopus Citations = 32; WoS Citations = 3; GS Citations = 36.0; Scopus SNIP (Source Normalised Impact per Paper): 1999 = 1.961; WoS Impact Factor: 2006 = 4.277 (2) - 2007=4.533 (5)
Citation count*36 (2020-05-27)
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