Structure and Dynamics of Conducting Poly(aniline) based Compounds
This thesis concerns one full study of structural and dynamical properties ofone family of conducting compounds of “plastdoped” polyaniline. Various experimental techniques have been combined as the wide angle X-ray diffraction and the small angle x ray scattering measurements (WAXS and SAXS), incoherent quasi-elastic neutron scattering techniques and numerical simulations of molecular dynamics based on a force field method. This combination allowed us to propose for these compounds one model of lamellar like stable structure with statistical fluctuation of the electronic density along the stacking direction of molecular layers. Moreover, in this model framework, it has been possible to study in detail the structural anisotropy of films and the structural evolution of the films under stretching. Finally, one second half of the thesis is devoted to the analysis of molecular dynamics data obtained by using quasi-elastic neutron scattering techniques. We could show that most of the dynamics in the 10-13-10-9 s time window concerns the motion of proton bore on the flexible tails of doping counter-ions. This dynamics has been found as very broadly distributed in time and also spatially along the plast-dopant tails and among the different plast-dopants as well. The results of numerical simulations agree remarkably well with experimental measurements. The atomic trajectories calculated in these simulations allowed us to recover all the scattering functions experimentally measured. The simulations have not only confirmed the starting hypothesis on which an analytical model for the dynamics was built but also revealed details on the way the dynamics is spatially distributed among the different plast-dopants.