Fully Doped Oligomers of Emeraldine Salt: Polaronic versus Bipolaronic Configuration

Abstract

Calculations for model oligomers of the emeraldine salt with UBLYP/6-31G*/PCM are performed. The models differ in number of monomers, in the position of the counterions (Cl(-)), and in multiplicity. The molecular features affected most prominently by the protonation, namely, structure, energetics, and electron and spin density partitioning are analyzed. The results show unequivocally that the studied molecular characteristics are essentially size independent. The octamer profiles of all parameters are repeated in the dodecamer and the hexadecamer. The bipolaronic forms are energetically more favorable than the polaronic ones within the chosen protocol. The electronic structure in the intermediate multiplicities differs from the bipolaronic and polaronic periodicity. The geometrical changes and electron density redistribution upon increase of multiplicity illustrate the pathway of intramolecular bipolaron-polaron conversion. The orbital analysis rationalizes the observed behavior of the oligomers.

Polymer dynamics in thin p-type conducting films investigated by ac-electrogravimetry. Kinetics aspects on anion exclusion, free solvent transfer, and conformational changes in poly(o-toluidine)

“…This fact agrees with the proposed model, which assumes that non-charged species transfer can be kinetically controlled by charge injection in polymeric backbone to induce conformational changes. At 0.32 V, the formation of the polaronic structure of POT films which twists the structure (coil structures owing to the anion-POT interactions) results in more water molecules that are able to be ejected from the film owing to conformational changes ( ′ close to 2 in Figure 6) [63,64]. Indirectly, this agrees with the expansion/contraction of film owing to the single/double bond transitions and to the accommodation of anions inside the film.…”

“…Figure 9 shows H The maximum of transfer rate takes place in both species around 0.32 V, as it is the case in Figure 8. As above, the creation of polaronic forms is a serious structural perturbation which can involve conformational movements of the molecular chains making the non-charged species transfer faster [63,64]. steps.…”

Self-doping of polyaniline prepared with the FeCl3/H2O2system and the origin of the Raman band of emeraldine salt at around 1375 cm−1

“…The other significant spectral changes observed in the region of ring‐stretching modes above 1450 cm −1 and ring‐deformation modes at 416 and 433 cm −1 , as well as changes in the region around 1240 cm −1 typical of ν(C–N) modes, indicate a partial distortion of the polaron lattice, which should take place during the assumed transformations.…”

Density Functional Theory Assessment of the Environment Polarity Effect on Polyaniline–Water Coupling

“…The bipolarons are calculated as singlets and the polaronsas triplets, as usually assumed and corroborated in our earlier study. 34 All models are subject to unrestrained geometry optimization followed by frequency analysis for confirmation of the minima. <S 2 > of the open shell systems is about 2.02 before and 2.00 after annihilationbased on these results it could be concluded that the triplet ground spin state is not spin contaminated.…”