Base and salt 3D forms of Emeraldine polymers EB-II and ES-II by Car-Parrinello Molecular Dynamics.

We have studied the structural properties of the three dimensional crystalline regions of the Emeraldine-II polymers, in the base EB-II and in the salt ES-II forms, by means of first principle Car-Parrinello molecular dynamics. We have first provided the detailed morphology of each chain in terms of bond lengths, bond angles, torsion angles, and twisting and bending of the chain backbone. We have then addressed the effects on the single chains due to packing of the polymer chains which form the 3D crystal. Starting from the “optimal” configuration obtained for the base form of the polymer, we have studied the process of protonation with HCl of the imminic nitrogens of the chains and the effect of the counterions between neighboring chains, produced by the oxidation of the polymer. In particular we have been able to give a vivid picture of the migration of the Clorine atoms along the polymer backbone and to provide a sound theoretical interpretation of the experimental X-ray diffraction spectra.