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Raman spectroscopic study on the structural changes of polyaniline during heating and cooling processes
Author(s) -
Zhang Jiaxin,
Liu Chen,
Shi Gaoquan
Publication year - 2005
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.21520
Subject(s) - polyaniline , raman spectroscopy , materials science , polymer chemistry , torsion (gastropod) , composite material , polymer , optics , polymerization , physics , medicine , surgery
Polyaniline (PANI) in three ground states—emeraldine base (EB), leucoemeraldine base (LEB), and pernigraniline base (PNB)—were studied by Raman spectroscopy in the temperature scale of −195 to about 375°C. The Raman spectral results demonstrated that a crosslinking reaction occurred on EB chains at high temperatures, whereas the phenyl torsion angles of EB chains decreased during the cooling process. LEB was unstable and was gradually converted to EB during the heating process, although its chain conformation remained stable by cooling. The spectral change tendency of PNB was similar to that of EB during the heating process. Although the torsion angle of PNB also decreased with decreasing temperature, like that of EB, this behavior was hard to observe experimentally because of the relatively “free ” rotation of its phenyl rings. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96:732–739, 2005