Vibrational study of short-range order and structure of polyaniline bases and salts

Raman and infrared reflection spectra in the backbone deformations and lattice modes range (10-1000 cm(-1)) of EB/ES-I and EB/ES-II polyanilines are discussed and compared with those of an oligomer (BQBBa) and of the constitutive bricks of the polyaniline skeleton: diphenylamine (BQB), N,N-'diphenyl-1,4-phenylenediamine (BBB), and N,N'-diphenyl-1,4-phenylenediimine (BQB). Short-range structure, scaling motif, and disorder are discussed. Emphasis is given to the relationship between hybridization, short-range structure, disorder, and optical properties. Ring, CH deformations, and librational/translational modes appear very sensitive to the static and dynamic disorder. Results show that vibrational spectroscopy allows to distinguish the two classes of polyaniline (ES-I and ES-II), whatever the inserted anion. The sketch of a continuous change of angle between the rigid virtual N-ring-N bond is proposed to describe the static orientational disorder.